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How different nanoparticles affect the rheological properties of aqueous Wyoming sodium bentonite suspensions
Abstract
Clay suspensions present complex microstructures in different environments and deep understanding of such microstructures is crucial to control their flow properties. Their rheological profile is closely linked with the structural association (3-D network) of bentonite particles. Nanomaterials are considered very good candidates for smart fluids formulation which can improve the performance of conventional drilling fluids. Their incorporation in water-bentonite suspensions endow complex microstructures and hence complex rheological behavior, which is still under investigation. This study aims to explore the micro-mechanisms involved on shaping this rheological behavior with samples of 7 wt% water-sodium bentonite suspensions containing 0.5 wt% each of, commercial Fe3O4, commercial SiO2 NP and custom-made (bare or citric acid coated) Fe3O4 NP at alkaline pH. We tried to achieve this by combining macroscopic measurements (rheological measurements) with microscopic measurements (i.e. TEM). A comprehensive physico-chemical characterization of the materials and suspensions was performed using X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), N2 adsorption-desorption isotherms and Fourier-transform infrared spectroscopy (FTIR). An effective drying process was adopted using freeze-granulation and freeze-drying (FG-FD) techniques in order to capture as accurately as possible the evolved microstructures of these aqueous bentonite suspensions at the different temperatures (25–60 °C). The results indicated that all samples exhibited a yield stress followed by a shear thinning behavior. The three parameter Herschel-Bulkley model provided excellent fit of the experimental data for all samples. HR-TEM images revealed that the association of the nanoparticles with bentonite particles in different configurations plays a crucial role in their rheological characteristics with the charge and the coating of the added nanoparticles being important factors in determining the magnitude of the effects observed. We hypothesize that attractive magnetic forces between the magnetite nanoparticles may suppress the electrostatic repulsions and thus they may play a key role in promoting the observed aggregation of the nanoparticles which in turn plausibly affected their rheological profile. A thorough examination and understanding of the evolution of such complex inter-particle structures may lead towards an optimal rheology control of such suspensions in a wide range of applications.
... This bonded water creates a current path, leading to a decrease in the ES reading. However, kaolin clay maintained the ES within the acceptable range greater than 400 V. 52,53 It is important to note that this reduction in ES does not necessarily indicate a true decrease in the overall stability of the drilling mud. Rather, it reflects the presence of these conductive clay particles. ...
... The escalation in PV from 24 to 31, 35, and 48 cP at 0, 5, 10, and 15 wt % is attributed to the introduction of more solids into the fluid; with the rise in kaolin clay amount, the friction will persistently rise. Therefore, kaolin clay above 10 wt.% yields PV out of the recommended range of PV. 52,53 The yield point (YP) is determined using a Bingham plastic model, where a linear relationship is assumed at elevated shear stress, as depicted in Figure 6 for the fluid with 15 wt % of kaolin clay. The point of intersection between this straight line and the y-axis shows a YP of 29 lb/100 ft 2 for that recipe. ...
... This moderate rise is deemed acceptable at lower concentrations, remaining within the approved range. 52,53 However, as the concentration of kaolin clay further increases, the escalation in the GS becomes more pronounced, exceeding the acceptable limits. At 15 wt %, the 10 s, 10 m, and 30 m GS show substantial increases of 171, 175, and 140%, respectively. ...
Drilling fluid is an essential component that helps keep the wellbore stable during fast drilling operations. However, problems arise when drilling fluids are contaminated with cuttings from the drilled formation, which impacts the wellbore integrity and fluid characteristics. The effectiveness of drilling operations depends on understanding and managing this relationship correctly. This study examined the influence of kaolin clay as drilling cuttings on barite-weighted oil-based drilling fluid (OBDF). Different quantities of kaolin clay (0, 5, 10, and 15 wt %) were intentionally added as impurities to the OBDF. The evaluation included important characteristics of drilling mud post-hot rolling such as fluid density, emulsion stability, rheology, and filtration performance under high-pressure and high-temperature (HPHT) conditions. The rheological behavior exhibits a gradual change at low solid concentrations but has a rapid increase as the percentage of solids becomes higher. The addition of kaolin clay, comprising less than 10 wt %, had no discernible impact on the yield point (YP). However, 15 wt % of kaolin clay increased the YP by 81%. Furthermore, the increase in gel strength is more pronounced at 10 and 15 wt %. Additionally, plastic viscosity (PV) increased by 19, 35, and 73% when adding 5, 10, and 15 wt % of kaolin clay solids. Incorporating kaolin clay led to increases in both the thickness of the filter cake and the filtrate amount. Kaolin clay reduced the electrical stability but sustained over 400 V at various concentrations. This study emphasizes the importance of understanding formation-drilling fluid interactions for successful drilling operations. Tailoring drilling fluids to specific formations, such as controlling clay content, can ensure wellbore stability and efficient drilling.
... The Fig. 15a & b are the photomicrographs of the filter cake for 0.8% ZnO drilling fluid. The ZnO nanoparticles have shown increased agglomeration [42] and ineffective plugging which have affected filtration profile [16,43]. However, despite the agglomeration of the nanoparticles in the filter cake of 0.8% ZnO nanoparticle drilling fluid, it has proved to be a better fluid loss control agent than the base drilling fluid without nanoparticles because to a certain degree, plugging of pores occurred and this resulted to low filtration leading to ineffective fluid loss control in the 0.8% ZnO nanoparticle drilling fluid. ...
... The detailed SEM investigation carried out in this study indicates that the process of filtration as observed from the SEM analysis of the filter cake from base drilling fluid without nanoparticles (Fig. 13a & b) appears to be very porous and permeable. While for 0.8% CuO filter cake ( Fig. 14a & b) and 0.8% ZnO filter cake ( Fig. 15a & b) cases, the nanoparticles are able to reduce the fluid loss considerably [35] by plugging the pores/holes observed in Fig. 13(a & b) [15,16,42] and this mechanism has resulted to thin and less permeable filter cake with low porosities as the volume of filter cake formed per cubic centimeter of filtrate has become very small [35]. However, the agglomeration of nanoparticles observed with 0.8% ZnO filter cake is because these magnetic particles can aggregate easily in water based fluids which results in bigger particles ( Fig. 15a & b) and leads to higher fluid losses because pristine inorganic nanoparticles are able to aggregate because of their high surface energy [15,42]. ...
... While for 0.8% CuO filter cake ( Fig. 14a & b) and 0.8% ZnO filter cake ( Fig. 15a & b) cases, the nanoparticles are able to reduce the fluid loss considerably [35] by plugging the pores/holes observed in Fig. 13(a & b) [15,16,42] and this mechanism has resulted to thin and less permeable filter cake with low porosities as the volume of filter cake formed per cubic centimeter of filtrate has become very small [35]. However, the agglomeration of nanoparticles observed with 0.8% ZnO filter cake is because these magnetic particles can aggregate easily in water based fluids which results in bigger particles ( Fig. 15a & b) and leads to higher fluid losses because pristine inorganic nanoparticles are able to aggregate because of their high surface energy [15,42]. The 0.8% CuO filter cake showed little or no aggregation (Fig. 14 a & b) hence the better hole plugging performance [16,42,43] giving rise to a low filtration velocity and a small volume of filter cake formed per cubic centimeter of filtrate and ultimately a thinner filter cake thickness [35]. ...
During the past decade, many researchers have reported on various improvements to water-based drilling fluid properties through the addition of different nanoparticles to improve the rheological properties, the thermal and electrical conductivity, and fluid loss control. Although various types of nanoparticles have been tested for their ability to improve the rheological and filtration properties of water-based drilling fluids at low pressure and temperature, some of them have not yet been tested at elevated pressure and temperature. In this study, the impact of different concentrations of ZnO and CuO nanoparticle additives on the rheological properties of a water-based drilling fluid at 25 °C, 50 °C and 80 °C, and on the filtration properties at 500 psi and 100 °C was studied. A range of ZnO and CuO nanoparticle concentrations, from 0.1 to 1 wt%, were prepared as nanofluids and introduced as additives (1 vol%) into prepared water-based base drilling fluids. The rheological properties for both nanoparticle-based drilling fluids showed a significant improvement over the base drilling fluid, with ZnO providing a better overall performance than CuO. Both nanoparticle-based drilling fluids were also observed to be more stable at elevated temperatures. For the filtration tests conducted under elevated pressure and temperature conditions (500 psi and 100 °C), a greater reduction in filtration loss was obtained at 0.8 wt% CuO nanoparticles (30.2%), compared to 0.8 wt% ZnO nanoparticles (18.6%). Mud cake thickness was also reduced, compared to the base fluid, with the CuO (27.6%) and ZnO (24.6%) nanoparticle fluids. These results demonstrate the ability of ZnO and CuO nanoparticles to enhance the properties of water-based drilling fluids, and their potential to be used as a high-efficiency filtration loss additive.
... In addition, there might be adsorption of polymer chains on the surface of bentonite 228 prevented the aggregation of bentonite at higher temperature [45]. Vryzas et al., [46] showed a similar 229 behavior for the iron oxide NPs in the water-bentonite suspension. This study shows that bentonite 230 forms a gel structure and aggregates at high temperature, due to the FF association of the platelets. ...
... In addition, there might be adsorption of polymer chains on the surface of bentonite prevented the aggregation of bentonite at higher temperature [45]. Vryzas et al. [46] showed a similar behavior for the iron oxide NPs in the water-bentonite suspension. This study shows that bentonite forms a gel structure and aggregates at high temperature, due to the FF association of the platelets. ...
In recent years, several studies have indicated the impact of nanoparticles (NPs) on various properties (such as viscosity and fluid loss) of conventional drilling fluids. Our previous study with commercial iron oxide NPs indicated the potential of using NPs to improve the properties of a laboratory bentonite-based drilling fluid without barite. In the present work, iron oxide NPs have been synthesized using the co-precipitation method. The effect of these hydrophilic NPs has been evaluated in bentonite and KCl-based drilling fluids. Rheological properties at different temperatures, viscoelastic properties, lubricity, and filtrate loss were measured to study the effect of NPs on the base fluid. Also, elemental analysis of the filtrate and microscale analysis of the filter cake was performed. Results for bentonite-based fluid showed that 0.019 wt% (0.1 g) of NPs reduced the coefficient of friction by 47%, and 0.0095 wt% (0.05 g) of NPs reduced the fluid loss by 20%. Moreover, for KCl-based fluids, 0.019 wt% (0.1 g) of additive reduced the coefficient of friction by 45%, while higher concentration of 0.038 wt% (0.2 g) of NPs shows 14% reduction in the filtrate loss. Microscale analysis shows that presence of NPs in the cake structure produces a more compact and less porous structure. This study indicates that very small concentration of NPs can provide better performance for the drilling fluids. Additionally, results from this work indicate the ability of NPs to fine-tune the properties of drilling fluids.
... In recent years, nanotechnology has aroused attention in the oil industry due to its vast applicability [17][18][19][20][21][22][23] and is being used in formulating drilling fluid, which is more often known as a nano-mud, to combat standing challenges and enhance the drilling performance [1,[24][25][26][27][28]. A nano-mud can be simply defined as any drilling fluid whose composition includes at least one type of mud additive in the nanoparticle size range of 1-100 nm [15,29]. Due to the extremely tiny particle size, which results in an exceptionally high surface area to volume ratio [30], nanoparticles are often stronger and more reactive than non-nanoparticles [31][32][33][34]. ...
... The GS is a measurement of the shear stress after the gel has set quiescently for some time [75][76][77]. A good GS is always required, as it would maintain the excessive circulation pressure needed to restart drilling operations [29,78,79]. Fig. 10 shows that the 10 s GSs of all OBM samples are within the recommended specification. ...
Oil-based mud (OBM), a non-Newtonian fluid, is known for its superior performance in drilling complex wells as well as combating potential drilling complications. However, the good performance may degrade under certain circumstances especially because of the impact of chemical instability at an elevated temperature. The same phenomenon occurs for water-based mud (WBM) when it is used in drilling under high temperature conditions. To prevent this degradation from occurring, numerous studies on utilizing nanoparticles to formulate smart fluids for drilling operations are being conducted worldwide. Hence, this study aims to evaluate the performance of nanosilica (NS) as a fluid loss reducer and a rheological property improver in both OBM and WBM systems at high temperature conditions. This study focuses on the impacts of different nanosilica concentrations, varying from 0.5 ppb to 1.5 ppb, and different mud weights of 9 ppg and 12 pg as well as different aging temperatures, ranging from ambient temperature to 300 ∘F, on the rheological performance of OBM and WBM. All the rheological properties are measured at ambient temperature, and additionally tests, including lubricity, electrical stability, and high-pressure high-temperature filtration measurements, are conducted, and rheological models are obtained. The performance of nanosilica is then studied by comparing each of the nanosilica-enhanced mud systems with the corresponding basic mud system, taking the fluid loss and rheological properties as the benchmark parameters. Nanosilica shows a positive impact on OBM and WBM, as the presence of nanosilica in the mud systems can effectively improve almost all their rheological properties.
... This is because the use of nanosilica allows for the formation of a more delicate gel (Salih and Bilgesu 2017). A good GS is always required as it helps maintain the necessary circulation pressure to restart drilling operations Anoop et al. 2019;Vryzas et al. 2019). The impact of different nanoparticle concentrations on the GS of graphite at 10 seconds is shown in Figs. 6 and 7 and Tables 6 through 9. Interestingly, it has been found that even with a small amount of nanoparticles, adding 0.3 ppb of nanocomposite can have a negative impact on GS. ...
The use of graphene-based lubricants in water-based drilling fluids (WDFs) has emerged as a promising avenue for enhancing their tribological properties, particularly under high-temperature (HT) conditions, by incorporating inorganic-material-based additives. For this study, we used a green and adsorption-based approach to prepare highly-dispersed graphite for modification, utilizing a cationic surfactant. Our research demonstrated the effective dispersion of the prepared graphite in water, characterized by low sedimentation rates and small contact angles in distilled water. The concentration dosage of Flowzan® on graphite was determined to be 0.02 g/g. To assess the effectiveness of modified graphite as a lubricating additive in water-based drilling, we conducted rheological studies and measured viscosity coefficients. The results revealed a significant decrease in the viscosity coefficient of the drilling fluid by 68% at 300°F when incorporating 0.05% modified graphene. Furthermore, the study investigated the thickness of six WDFs under high-temperature, high-pressure (HTHP) conditions. The addition of 3% graphene expansion resulted in a notable reduction in the volume of HTHP liquid filtrate by up to 30% compared with the control. These experimental findings underscore the advantageous effects of nanoparticle addition on properties such as lubricity, rheology, fluid loss, and thermal stability, potentially revolutionizing the drilling process. In addition to evaluating the performance of modified graphite, we analyzed its primary, crystalline, and morphological properties using various techniques, including particle size tests, zeta potential tests, Fourier transform infrared (FTIR), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM). These analyses elucidated the lubrication mechanism, demonstrating that graphite modification primarily occurred through physical adsorption without altering the crystal structure. These insights provide valuable guidance for the development of high-performance WDFs tailored to endure the challenges of drilling operations.
... This shear-thinning behaviour can be described by the power-law model (Eq. (2)), which relates shear stress (τ) to shear rate (γ) and consistency index (K) as well as flow behaviour index (n) [61,62]: ...
The presence of high permeability zones causes the injected fluid/gas to bypass the low permeability pores, initiating an early breakthrough. One of the most influential and promising methods to control fluid bypass is fluid diversion using an emulsion/chemical agent placed at the highly permeable zone, which eventually diverts the injected fluids to a less permeable region. Chitin Nanocrystal (ChiNCs), a naturally abundant nanomaterial with high oil-water interfacial adsorption, has attracted significant interest as an emulsion stabilizer in various applications. Unlike traditional surfactants, ChiNCs offer a sustainable alternative by stabilizing the emulsion, providing long-term stability and enhanced viscoelasticity. This study presents a novel, eco-friendly solution by exploring ChiNCs as pickering emulsions stabilizers for conformance control in porous media. The ChiNCs were prepared through acid hydrolysis of chitin powder derived from crab shells. ChiNCs and their emulsions were analysed using Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), Zeta (ζ)-Potential, Cross-Polarized Microscopy (CPM), and rheometer. The presence of ChiNCs in the emulsion resulted in shear-thinning behaviour, making it suitable for conformance control. Core-flood experiment results confirmed the effectiveness of ChiNCs-stabilized emulsions for permeability reduction. Pressure drops and permeability reductions increased with larger emulsion slug sizes, indicating successful pore plugging and improved fluid diversion. The highest-permeability reduction with 85.6% were obtained with 0.7 pore volume (PV) of emulsion injection for a short time. In contrast, injecting 0.5 PV of the emulsion led to a significant and sustained permeability reduction of 80.8%. To the best of the authors' knowledge, this is the first application of chitin nanocrystals in fluid diversion and conformance control. The ζ-potential over +20 mV within the pH range 3–6 was sufficient to achieve the highest colloidal stability via electrostatic effect and good ChiNCs suspension transparency. The microstructure observed under the CPM correlates with the rheological behavior, showing that the ChiNCs provide a significant steric barrier to coalescence, thus enhancing the emulsion's resistance to flow and deformation.
... The effects of deflocculant concentration on YP are presented in Fig. 5a and b for RTLS and ICD, respectively. In general, exposing WBDF to a high-temperature environment will increase the Bingham YP (Ahmad et al. 2018;Annis and Smith 1996;Hafshejani et al. 2016;Moslemizadeh et al. 2015;Vryzas et al. 2019Vryzas et al. , 2017. The YP of WBDF at 93 °C doubled the YP of the BHR sample before the values increased significantly to 30.1, 35.8, and 46 Pa for 121, 149, and 177 °C, respectively. ...
Bentonite suspension in water-based drilling fluid is susceptible to deterioration in high-temperature environments, hence requiring a deflocculant to stabilize the solid particles. Considering the use of highly toxic chrome-based deflocculant in the industry, Rhizophora spp. tannin-lignosulfonate (RTLS) was synthesized in this study as an alternative deflocculant. A viscometer was used to study the rheological properties, and the filtration performance was evaluated using low-pressure low-temperature and high-pressure high-temperature filter press in accordance with the American Petroleum Institute standard procedure. The addition of 0.5 wt% RTLS to water-based drilling fluid (WBDF) was effective in a significant reduction of the plastic viscosity (PV) and yield point (YP) of WBDF at elevated temperatures. As the amount of RTLS added to the suspension exceeds 0.5 wt%, the effect on PV and YP becomes negligible. A higher fluid loss of 13 mL was observed in the WBDF without RTLS aged at 177 °C. The addition of 2.0 wt% RTLS reduced the fluid loss to 10.7 mL. This suggests that RTLS is an effective deflocculant that can be used to improve the filtration properties of WBDF at high temperatures. The morphology of RTLS filter cakes was examined using field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDX). The interlayer between clay particles was identified as RTLS, a natural additive that plays a vital role in enhancing filtration while minimizing fluid loss. The outcomes of this research are promising, and this non-toxic deflocculant has the potential to replace chrome-based deflocculants that are still in use for borehole drilling.
... However, it is essential to acknowledge that the behavior of silica nanoparticles, whether in dispersed or colloidal sol form, often leads to agglomeration, thereby impacting the efficiency and properties of these nanoparticles (Javeri et al., 2011). Introducing SiO 2 nanoparticles may result in weaker structures and lower yield stress values compared to the base fluid (Vryzas et al., 2019). Surface modifications and excessive functional groups can also influence the desired outcomes by binding or interacting with chemical species (Kong et al., 2013). ...
... While electrochemical sensors have many advantages, there are also some drawbacks associated with their use. Many groundbreaking developments in fields such as biomedical and genetics [46,47], biotechnology [48][49][50][51][52], opto-electronics [53], fluid dynamics [54,55], alternative energy sources [56][57][58][59][60][61][62], environmental treatment [63][64][65], energy storage and conversion systems [66][67][68], sensors [69][70][71] etc. have been made possible by extraordinary research and development activities in the production and application areas of nanostructures, and the engineering of novel spectrophotometric technique is one of these technological innovations. ...
Nowadays, atropine has been highlighted because of its anticholinergic effect and contamination in foodstuffs, and therefore, using an accurate and sensitive method for its determination is crucial in human health and food safety. In this study, a novel spectrophotometric method was suggested for the swift quantification of atropine. The proposed method was based on the formation of red ion-pair complexes between the drugs and the cyanidin reagent extracted from red cabbage (RC). In this regard, the effect of pH, time, and temperature was explored and optimized. According to the results, atropine determining was shown the best performance in pH 2 at room temperature in 30 min. In addition, this method revealed linear responses from 10 nM to 1 µM of atropine with limit of detection (LOD) value of 0.0019 µM. Also, the selectivity value of this method was investigated in the presence of some drugs with the same structure and some common species as interferences. The results verified no interference in atropine determination, as well as, the results obtained from repeatability (RSD ⁓ 2.56) of this method were acceptable. Moreover, the applicability of this method was tested in buckwheat and atropine sulfate as food and pharmaceutical real sample, respectively. Real sample analysis was carried out with the standard addition method and the recovery percentages (96.54–104.87%) witnessed the high capability of this method in atropine determination.
Graphical abstract
... Nanotechnology is an interdisciplinary field based on structures with 1.0 nm to several hundred nanometers dimensions, which has led to an explosive revolution in research activities [10,11]. Thanks to the recent advances in nanomaterial science, state-of-art advances in catalyst engineering [12,13], energy [14,15], biotechnology and biomedical applications [16][17][18][19][20][21], genetic engineering [22], mechanical and petroleum engineering [23], optics and electronics [24], food safety, hydrogen production and storage [25][26][27], and environmental applications [28][29][30][31], sensors [32][33][34], etc. have been accelerated substantially. Among developed nanostructures with unique properties and exceptional performance, nanobiomaterials have received much attention due to the synergistic role of their extraordinary small size and biological properties [35]. ...
Global waste production is anticipated reach to 2.59 billion tons in 2030, thus accentuating issues of environmental pollution and health security. 37 % of waste is landfilled, 33 % is discharged or burned in open areas, and only 13.5 % is recycled, which makes waste management poorly efficient in the context of the circular economy. There is therefore a need for methods to recycle waste into valuable materials through resource recovery process. Progress in the field of recycling is strongly dependent on the development of efficient, stable, and reusable, yet inexpensive catalysts. In this case, a growing attention has been paid to development and application of nanobiocatalysts with promising features. The main purpose of this review paper is to: (i) introduce nanobiomaterials and describe their effective role in the preparation of functional nanobiocatalysts for the recourse recovery aims; (ii) provide production methods and the efficiency improvement of nanobaiocatalysts; (iii) give comprehensive description of valued resource recovery for reducing toxic chemicals from the contaminated environment; (iv) describe various technologies for the valued resource recovery; (v) state the limitation of the valued resource recovery; (vi) and finally economic importance and current scenario of nanobiocatalysts strategies applicable for the resource recovery processes.
... The main issue in the design and optimization of the adsorption process is to tailor a cost-effective, environmentally friendly adsorbent with high adsorption capacity. The tremendous efforts in tailoring up-and-coming nanomaterials allow researchers to utilize these nanostructures in a wide range of application areas including sensors (Zhang and Karimi-Maleh, 2023), energy (Romanos et al., 2018a), hydrogen generation and its storage (Romanos et al., 2018b(Romanos et al., , 2019, genetic engineering applications (Xian et al., 2019), biotechnology (Musa et al., 2018;Bechnak et al., 2020), catalyst (Karaman, 2022), fluid dynamics (Vryzas et al., 2019), optics and electronics , etc. Amongst these application areas utilization of nanomaterials in environmental remediation is one of the most attractive ones. In this regard, various materials such as zeolites (Migliorin et al., 2022), organic-inorganic hybrid nanomaterials (Attia et al., 2022;Wu et al., 2022), and metal-organic frameworks (Bagheri et al., 2023;Cheng et al., 2023)have investigated as efficient adsorbents up till now. ...
Herein, it was aimed to optimize the removal process of Azithromycin (Azi) from the aquatic environment via CoFe2O4@NiO nanoparticles anchored onto the microalgae-derived nitrogen-doped porous activated carbon (N-PAC), besides developing a colorimetric method for the swift monitoring of Azi in pharmaceutical products. In this study, the Spirulina platensis (Sp) was used as a biomass resource for fabricating CoFe2O4/NiO@N-PAC adsorbent. The pores of N-PAC mainly entail mesoporous structures with a mean pore diameter of 21.546 nm and total cavity volume (Vtotal) of 0.033578 cm3. g-1. The adsorption studies offered that 98.5% of Azi in aqueous media could remove by CoFe2O4/NiO@N-PAC. For the cyclic stability analysis, the adsorbent was separated magnetically and assessed at the end of five adsorption-desorption cycles with a negligible decrease in adsorption. The kinetic modeling revealed that the adsorption of Azi onto the CoFe2O4/NiO@N-PAC was well-fitted to the second-order reaction kinetics, and the highest adsorption capacity was found as 2000 mg. g-1 at 25 °C based on the Langmuir adsorption isotherm model at 0.8 g. L-1 adsorbent concentration. The Freundlich isotherm model had the best agreement with the experimental data. Thermodynamic modeling indicated the spontaneous and exothermic nature of the adsorption process. Moreover, the effects of pH, temperature, and operating time were also optimized in the colorimetric Azi detection. The blue ion-pair complexes between Azi and Coomassie Brilliant Blue G-250 (CBBG-250) reagent followed Beer's law at wavelengths of 640 nm in the concentration range of 1.0 μM to 1.0 mM with a 0.94 μM limit of detection (LOD). In addition, the selectivity of Azi determination was verified in presence of various species. Furthermore, the applicability of CBBG-250 dye for quantifying Azi was evaluated in Azi capsules as real samples, which revealed the acceptable recovery percentage (98.72-101.27%). This work paves the way for engineering advanced nanomaterials for the removal and monitoring of Azi and assures the sustainability of environmental protection and public health.
... Therefore, synthesizing a green catalyst that can reduce NO without using ammonia is crucial in resolving the abovementioned issues. The state-of-art advances in nanomaterial science and technology have paved the way for designing and fabricating of up-and-coming nanohybrids to be utilized in various range of application areas including environment [9][10][11], biotechnology [12][13][14][15], catalyst [16,17], sensor [18,19], hydrogen production and storage [20][21][22][23], genetics [24], optics [25], electronics [26], energy [27][28][29], fluid dynamics and mechanics [30,31], food control, etc. Thus, it can be speculated that it is possible to engineer a novel nanomaterial to be employed as a catalyst in NO reduction reaction. ...
In this study, the catalytic reduction reaction of NO (directly) without the presence of ammonia (NH3) was studied on the Ni-embedded graphene ([email protected]) layer using periodic Density Functional Theory (DFT) calculations. Ni-embedded graphene surface can be synthesized experimentally and it is predicted that it will cost much less than single crystal surfaces due to the economic usage of the transition metal atoms. First of all, by optimizing the geometric structure of the [email protected] layer, crucial geometric features and electron density differences (EDD) were obtained. Based on the different adsorption configurations of NO molecule, the reduction reaction was investigated by Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) based mechanisms. Finally, N2O degradation was analyzed in detail. It is shown that the Eley-Rideal model is a more dominant mechanism on the [email protected] surface than the other model. In addition, all proposed reaction pathways for NO reduction are exothermic. This information can be used for the research and development of graphene-based materials for NO reduction; paves the way for finding new Ni-based catalysts based on active single transition metal atom embedded on different kind of defects.
... In this regard, high-performance nanomaterials have garnered great attention. The recent advances in nanomaterial science and technology have fueled the researchers to pave the way for engineering up-and-coming low-cost nanostructures to be utilized in biotechnology (Musa et al., 2018;Bechnak et al., 2020;Xian et al., 2019), energy (Karaman, 2022;Karimi-Maleh et al., 2022;Jafarzadeh et al., 2022;Wu et al., 2021;Kandathil et al., 2021), sensors (Ghalkhani et al., 2022;Mehmandoust et al., 2021;Manjushree et al., 2022), hydrogen production and storage (Romanos et al., 2018(Romanos et al., , 2019Zhang et al., 2021a), catalysts (Meenu et al., 2021;Song et al., 2021;Xu et al., 2022), mechanical engineering applications (Vryzas et al., 2019;Goei et al., 2022;Hosseinzadeh et al., 2021;Nadeem et al., 2020), optics and electronics Zhang et al., 2021b), food safety (Deka et al., 2022), carbon capture (Hassan et al., 2021), etc. Amongst the variety type of application areas environmental remediation, including the removal/degradation of organic pollutants, has garnered substantial attention (Lekshmi et al., 2021;Vishnu et al., 2021). ...
p_Aminophenol, namely 4-aminophenol (4-AP), is an aromatic compound including hydroxyl and amino groups contiguous together on the benzene ring, which are suitable chemically reactive, amphoteric, and alleviating agents in nature. Amino phenols are appropriate precursors for synthesizing oxazoles and oxazines. However, since the toxicity of aniline and phenol can harm human and herbal organs, it is essential to improve a reliable technique for the determination of even a trace amount of amino phenols, as well as elimination or (bio)degradation/photodegradation of it to protect both the environment and people's health. For this purpose, various analytical methods have been suggested up till now, including spectrophotometry, liquid chromatography, spectrofluorometric and capillary electrophoresis, etc. However, some drawbacks such as the requirement of complex instruments, high costs, not being portable, slow response time, low sensitivity, etc. prevent them to be employed in a wide range and swift in-situ applications. In this regard, besides the efforts such as (bio)degradation/photodegradation or removal of 4-AP pollutants from real samples, electroanalytical techniques have become a promising alternative for monitoring them with high sensitivity. In this review, it was aimed to emphasize and summarize the recent advances, challenges, and opportunities for removal, degradation, and electrochemical sensing 4-AP in real samples. Electroanalytical monitoring of amino phenols was reviewed in detail and explored the various types of electrochemical sensors applied for detecting and monitoring in real samples. Furthermore, the various technique of removal and degradation of 4-AP in industrial and urban wastes were also deliberated. Moreover, deep criticism of multifunctional nanomaterials to be utilized as a catalyst, adsorbent/biosorbent, and electroactive material for the fabrication of electrochemical sensors was covered along with their unique properties. Future perspectives and conclusions were also criticized to pave the way for further studies in the field of application of up-and-coming nanostructures in environmental applications.
... Thanks to the recent steps in nanomaterial science and technology, it is possible to use advanced multifunctional nanomaterials in various application areas including environmental science and technology Mubashir et al., 2022;Ali et al., 2022;Deng et al., 2017;Wang et al., 2020;Song et al., 2022), food safety (Karimi-Maleh et al., 2022b;Ghalkhani et al., 2022b), energy (Karaman, 2021a(Karaman, , 2022Gao et al., 2021;Xu et al., 2022;Cheng et al., 2021;Romanos et al., 2018a), catalyst (Jafarzadeh et al., 2022;Karaman, 2021b;Hajipour and Malek, 2021;Su et al., 2021), biotechnology (Sahoo et al., 2021;Sajid et al., 2022;Khan et al., 2020;Isacfranklin et al., 2020;Ameen et al., 2020;Musa et al., 2018;Bechnak et al., 2020;Jaafar et al., 2022), sensors (Ensafi et al., 2013;Ahmed et al., 2021;Khoobi et al., 2019;Danial et al., 2021), fluid dynamics (Vryzas et al., 2019), hydrogen storage and production (Romanos et al., 2018b(Romanos et al., , 2019, optics , genetics (Xian et al., 2019), etc. Among the various types of nanostructures, metal/metal oxide-based nanocomposites have garnered substantial attention for the fabrication of electrochemical sensors due to their superior physicochemical characteristics including excellent conductivity, thereby enhancing the electrochemical performance (Sanati and Faridbod, 2022). ...
A crucial problem that needs to be resolved is the sensitive and selective monitoring of chlorophenol compounds, specifically 4-chlorophenol (4-CP), one of the most frequently used organic industrial chemicals. In light of this, the goal of this study was to synthesize Fe3O4 incorporated cellulose nanofiber composite (Fe3O4/CNF) as an amplifier in the development of a modified carbon paste electrode (CPE) for 4-CP detection. Transmission electron microscopy (TEM) was used to evaluate the morphology of the synthesized nanocatalyst, while differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) techniques were implemented to illuminate the electrochemical characteristics of the fabricated sensor. The ultimate electrochemical sensor (Fe3O4/CNF/CPE) was used as a potent electrochemical sensor for monitoring 4-CP in the concentration range of 1.0 nM-170 μM with a limit of detection value of 0.5 nM. As a result of optimization studies, 8.0 mg Fe3O4/CNF was found to be the ideal catalyst concentration, whereas pH = 6.0 was chosen as the ideal pH. The 4-CP's oxidation current was found to be over 1.67 times greater at ideal operating conditions than it was at the surface of bare CPE, and its oxidation potential decreased by about 120 mV. By using the standard addition procedure on samples of drinking water and wastewater, the suggested capability of Fe3O4/CNF/CPE to detect 4-CP was further investigated. The recovery range was found to be 98.52-103.66%. This study paves the way for the customization of advanced nanostructure for the application in electrochemical sensors resulting in beneficial environmental impact and enhancing human health.
... Then, the resulting mixture was placed in an oven at 105 C for 16 h. At the last step, the obtained CMCbentonite was passed through sieve #200 according to the standard to prepare for the free swell index test (Alaskari and Teymoori, 2017;Benchabane and Bekkour, 2008;Di Emidio et al., 2011;Janssen et al., 2015;Menezes et al., 2010;Vryzas et al., 2019). ...
Heavy metals are prevalent in electrical and electronic waste. The sealing of this type of waste disposal site is critical due to the existence of toxic materials. In this regard, Geosynthetic Clay Liners (GCLs) are widely used as one of the most common engineered barriers at disposal sites. Recently, attention has been drawn to modifying the bentonite of GCL with polymers to improve barrier performance against leachate. The aim of this study was to evaluate the swelling performance of the raw and modified GCL with a hydrophilic anionic polymer called CarboxyMethyl Cellulose (CMC) with weight percentages of 8, 10, and 12 of dried bentonite against synthetic heavy metals’ leachate, containing copper and zinc, simultaneously and separately, based on ASTM D5890. It was found that adding this polymer could improve the swelling rate of the GCLs. The optimum CMC rate for modified GCLs exposed to the cationic solutions, including copper and zinc, was estimated at 10%. It could also be noted that the swell index of both natural and modified bentonites against solutions, including two cations of copper and zinc, simultaneously, was more sensitive to the changes in zinc ion concentration versus copper metal concentration.
... As a result, an increasing number of researchers are focusing on developing innovative thrifty metal electrocatalysts with high catalytic activity. Thanks to the recent advances in the nanomaterial science and technology, up till now the researches have engineered numerous types of nanostructures to be utilized in various applications including biotechnology [12,13], pharmacy [14,15], environment [16][17][18][19], catalyst [20][21][22][23][24], energy [25][26][27][28][29], rheology [30], food analysis [31][32][33], optics [34,35], sensors [36], electronics [37,38], heat transfer applications [39,40], etc. ...
Herein, a simple hydrothermal approach was employed to synthesize a homogeneous and compact ZnFe2O4 nanoparticles on the surface of ZrO2 (ZnFe2O4-ZrO2), and it was utilized as a supporting-material for Pt nanoparticles. The fabricated ZnFe2O4-ZrO2 and ZnFe2O4-ZrO2/Pt nanoarchitectures were employed as an electrode material for the supercapacitor cells, and an electrocatalyst for the methanol oxidation reaction, respectively. The Pt nanoparticles were electrochemically deposited on the ZnFe2O4-ZrO2 support. The electrochemical characterizations illustrated that ZnFe2O4-ZrO2 supported Pt was of a peak current density of 104.74 mA/cm², which was 1.73 more than the peak current density of Pt without the use of nanocomposite support and strong cycling stability of 110 percent after 150 cycles for the methanol oxidation reaction. As a supercapacitor electrode, ZnFe2O4-ZrO2 offered a high specific capacitance of 193.76F/g at a current density of 1.0 A/g, an appropriate rate efficiency (102.4 F/g at current density of 8 A/g), and strong cycling stability of 93 % after 250 galvanostatic charge–discharge revealing the high cycle stability of the nanocomposite. The superb electrochemical behavior of the ZnFe2O4-ZrO2 electrode was ascribed to the low internal charge resistance and ion diffusion resistance. The more ion/electron pathways of diffusion and a suitable contact area with the electrolyte, and the strong synergistic interaction between the components conferred exceptional conductivity and structural durability on the electrode. The results paved the new avenues for nanoengineering of up-and-coming metal-based nanoarchitectures to be utilized in energy storage and conversion systems.
... This model is considering an initial shear stress value for fitting the real behavior of drilling fluid, which is an enhancement model from the power-law model. The three Herschel-Bulkley rheological parameters were estimated according to the following equation [40]: ...
Advancements in horizontal drilling technologies are utilized to develop unconventional resources, where reservoir temperatures and pressures are very high. However, the flocculation of bentonite in traditional fluids at high temperature and high pressure (HTHP) environments can lower cuttings transportation efficiency and even result in problems such as stuck pipe, decreased rate of penetration (ROP), accelerated bit wear, high torque, and drag on the drill string, and formation damage.
The major purpose of the present research is to investigate the performance of low bentonite content water-based fluids for the hole cleaning operation in horizontal drilling processes. Low bentonite content water-based drilling fluids were formulated by replacing a specified quantity of bentonite with a small fraction of cellulose nanoparticles (CNPs), including cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs). The
concentration of CNPs was changed from 0.15 wt% up to 0.60 wt% and the bentonite content was reduced from 6 to 0 wt%, which leads to a reduction of solid contents from 13.34 to 6.71 wt%. The flow-loop experiments were accomplished on a sophisticated purpose-built flow rig by circulating the tested fluid samples into the test section in a horizontal position, considering the influence of drill pipe rotation, flow rates, cuttings sizes, and drill pipe eccentricity. The results show that the low solid fluids displayed a considerable enhancement in cuttings removal efficiency, especially with 0.15 wt% of the
concentration CNPs and 4.5 wt% of the bentonite contents. The morphology of CNPs played a vital role in improving the rheological properties of the water-based drilling fluids.
... In this case, a surfactant bilayer is formed, which assures electrostatic contact with particle surfaces as well as hydrophilic head direction toward the aqueous solution. Crosslinking occurs when the surface of a nanoparticle is considerably bigger than the cross section of wormlike micelles [24]. ...
Worm-like micelles are of special interest among the many forms of surfactant aggregates because of their usefulness in research and technology. Micelles are elongated, flexible aggregates formed by amphiphilic molecules spontaneously self-organizing in liquids. The nature of the surfactant determines its unique shape, which may be altered by mixing it with other substances or changing physicochemical variables like as temperature, pH, or salinity. The rheology of viscoelastic fluid systems is currently being modified using nanoparticles. This method, which was just introduced about 10 years ago, has shown to be highly promising, producing significant improvements in rheological properties, particularly at reservoir temperatures. The goal of this research is to investigate and assess the rheology of an aqueous cationic surfactant solution based on graphene oxide nanoparticles. The thermodynamics, structure, and rheology of nanoparticle-based cationic surfactant solutions were investigated experimentally. According to structural and thermodynamic investigations in surfactant-nanoparticle mixtures, micelle-nanoparticle interactions arise as physical crosslinks between micelles. The existence of these interactions is shown to generate considerable viscosity and viscoelasticity in wormlike micelles, even when the fluid is Newtonian in the absence of nanoparticles. The viscosity, shear modulus, and relaxation time all increase as particle concentration increases. Adding nanoparticles generates a network of micellar entanglements as a result of that. Our results demonstrate that adding nanoparticles to surfactant solutions provides for a one-of-a-kind method of altering fluid rheology under a range of circumstances.
... This model is considering an initial shear stress value for fitting the real behavior of the drilling fluid, which is an enhancement model from the power-law model. The three Herschel-Bulkley rheological parameters were estimated according to the following equation [24]: ...
Extended reach drilling (ERD) wells with a horizontal and highly deviated section are widely applied in the oil and gas industry because they provide higher drainage area than vertical wells and hence increase the productivity or injectivity of the well. Among many issues encountered in a complex well trajectory, poor hole cleaning is the most common problem, which occurs mainly in the deviated and horizontal section of oil and gas wells. There are significant parameters that have a serious impact on hole cleaning performance in high-angle and horizontal sections. These include flowrate, rheology, and density of the drilling fluid, drill string eccentricity, pipe rotation, and cuttings size. It has been recognized that the action of most of these parameters to transport drilled cuttings is constantly a point of controversy among oilfield engineers. In the present study, extensive experiments were conducted in an advanced purpose-built flow rig to identify the main parameters affecting on circulate the cuttings out of the test section in a horizontal position. The flow-loop simulator has been designed to allow easy variation of operational parameters in terms of flowrate, mud density, drill string eccentricity, pipe rotation, and cuttings size. In addition, the study covers the impacts of laminar, transition, and turbulent flow regimes. The goal of such variation in the operational conditions is to simulate real-field situations. The results have shown that drill string rotation and flowrate were the operational parameters with the highest positive influence on the cuttings transports process. In contrast, drill pipe eccentricity has a negative influence on cuttings removal efficiency. The cuttings transportation performance is further improved by pipe rotation at different levels of eccentricity, especially at fully eccentric annuli. It was also shown that larger cuttings appeared to be easier to remove in a horizontal annulus than smaller ones. The experimental results would provide a more in-depth understanding of the relationship between drilling operation parameters and hole cleaning efficiency in ERD operations. This will help the drilling teams to realize what action is better to take for efficient cutting transportation.
... This model is considering an initial shear stress value for fitting the real behavior of drilling fluid, which is an enhancement model from the power-law model. The three Herschel-Bulkley rheological parameters were estimated according to the following equation (Vryzas et al., 2019): ...
Efficient cuttings transport is important for achieving safe and successful drilling operations. However, poor hole cleaning is considered to be one of the main issues that happens frequently in horizontal and highly deviated wells. The selection of the drilling fluids with enhanced rheological properties is one of the effective methods to increase cuttings transportation efficiency. The major purpose of the present research is to investigate the application of silica (SiO2) nanoparticles in improving hole cleaning in extended reach drilling (ERD) operations.
Nanocomposite drilling fluids were prepared by adding silica nanoparticles into water-based mud (WBM) at different weight percent concentrations (0.1–1.5 wt%). The flow loop experiments were performed on a sophisticated purpose-built flow rig by circulating the tested fluid samples into the test section in a horizontal position, considering the influence of drill pipe rotation, flow rates, cuttings sizes, mud density, and drill pipe eccentricity. In addition, the study covers the impacts of laminar, transition, and turbulent flow regimes. The goal of such variation in the operational parameters is to simulate real field conditions.
The results indicated that the addition of the silica nanoparticles to WBM increases the colloidal interactions with cuttings, therefore leading to a substantial enhancement in cuttings removal efficiency especially with the higher concentration of silica nanoparticles. It was shown that nanoparticles in drilling fluid increase cuttings transport by 20.32%– 32.75% for different nanocomposite water-based drilling fluids used in this study. The proposed investigation demonstrates the feasibility of using silica nanoparticles in WBM to enhance the capability of drilling fluids in transporting and circulating drilled cuttings out of the wellbore. Furthermore, the results of this project would provide a more reliable understanding of the relationship between drilling operation parameters and hole cleaning performance in ERD operations.
... The zeta-potential measurements indicated that Fe 2 O 3 and Fe 3 O 4 NPs, with positive surface charge, embedded in the randomly formed pore structure on the surface of bentonite particles. This resulted in the generation of a better bentonite/platelet structure, thus producing low-porosity/low-permeability filter cake (Barry et al. 2015; Al-Yasiri and Wen 2019; Vryzas et al. 2019). Fig. 4 is a schematic illustration of the attraction between the iron oxide NPs and bentonite. ...
Invasion of mud filtrate while drilling is considered as one of the most common sources of formation damage. Minimizing formation damage, using appropriate drilling fluid additives that can generate good-quality filter cake, provides one of the key elements for the success of the drilling operation. This study focuses on assessing the effect of using different types of nanoparticles (NPs) with Ca-bentonite on the formation damage and filter cake properties under downhole conditions.
Four types of oxide NPs were added to a suspension of 7 wt% of Ca-bentonite with deionized water: ferric oxide (Fe2O3), magnetic iron oxide (Fe3O4), zinc oxide (ZnO), and silica (SiO2) NPs. The NPs/Ca-bentonite suspensions were then used to conduct the filtration process at a differential pressure of 300 psi and 250°F using a high pressure/high temperature (HP/HT) API filter press. Indiana limestone disks of 1 in. thickness were examined, as the filter medium, to simulate the formation in the filtration experiments. Computed-tomography (CT) scan technique was used to characterize the deposited filter cake and evaluate the formation damage that was caused by using different fluid samples.
The results of this study showed that the filtrate invasion is affected by the type of NPs, which is also affecting the disk-porosity. Using 0.5 wt% of Fe2O3 NPs with the 7 wt% Ca-bentonite fluid showed a higher potential to minimize the amount of damage. The average porosity of the disk was reduced by 1.0%. However, adding 0.5 wt% of Fe3O4, SiO2, and ZnO NPs yielded a disk-porosity decrease by 4.7, 13.7, and 30%, respectively. The decrease in the disk-porosity after the filtration is directly proportional to the volume of the invaded filtrate. Compared to that of the base fluid, the best reduction in the filtrate invasion was achieved when adding 0.5 wt% of Fe2O3 and Fe3O4 NPs by 42.5 and 23%, respectively. The results revealed that Fe2O3 and Fe3O4 NPs can build better Ca-bentonite-platelet structure and thus, a good-quality filter cake. This is due to their positive surface charge and stability in suspensions, as demonstrated by zeta-potential measurements, which can minimize formation damage. Increasing the concentration of Fe3O4 NPs from 0.5 to 1.5 wt% showed an insignificant variation in the filtrate invasion, spurt loss, and filter cake permeability; however, an increase in the filter cake thickness as well as the amount of damage created was observed. The 1.5 wt% of ZnO NPs showed a better performance compared to the case having 0.5 wt% of ZnO NPs, but in the meanwhile it showed the lowest efficiency when compared to the other types of NPs. This could be due to their surface charge and suspensions’ instability.
Results of this work are useful in evaluating the drilling applications using Ca-bentonite-based fluids modified with NPs as an alternative to the commonly used Na-bentonite. Additionally, it might help in understanding the NPs/Ca-bentonite interaction for providing more efficient drilling operations and less formation damage.
... Much higher values of R 2 (closer to 1) and much lower values of root-mean-square error (RMSE, closer to 0) proved that the Herschel−Bulkley model provided a better fit for the shear stress−shear rate curve, followed by the power-law model, and finally the Bingham plastic model. 41,42 Therefore, this paper chooses to use the Herschel−Bulkley model to describe the rheology of drilling fluids. As can be seen in Table 1, as the E-AM/AMPS concentration increased from 0.5 to 1, 1.5, and 2 wt %, the flow pattern index (n) of bentonite/E gradually decreased from 0.81914 to 0.77474, 0.74015, and 0.71639 and the consistency coefficient (K) obviously increased from 0.03655 to 0.08641, 0.17189, and 0.30416. ...
Acrylamide polymers were widely used as oilfield chemical treatment agents because of their wide viscosity range and versatile functions. However, with the increased formation complexity, their shortcomings such as poor solubility and low resistance to temperature, salt, and calcium were gradually exposed. In this paper, acrylamide (AM)/2-acrylamide-2-methyl-1-propane sulfonic acid (AMPS) copolymers were synthesized by aqueous solution polymerization and inverse emulsion polymerization, respectively. The aqueous polymer (W-AM/AMPS) and the inverse emulsion polymer (E-AM/AMPS) were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (¹H NMR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and particle size analysis. The rheological properties, filtration properties, and sodium ion (Na⁺) and calcium ion (Ca²⁺) resistance were investigated. The results showed that E-AM/AMPS not only had a dissolution speed 4 times faster than that of W-AM/AMPS but also had superior shear-thinning performance both before and after aging. The filtration property of the bentonite system containing 2 wt % E-AM/AMPS was also better than that of the bentonite system containing 2 wt % W-AM/AMPS. In addition, E-AM/AMPS also exhibited extremely high tolerance for Na⁺ and Ca²⁺. The huge difference between rheological and filtration properties of E-AM/AMPS and W-AM/AMPS in drilling fluid can be attributed to the differences in the polymer microstructure caused by the two polymerization methods. Both FTIR and ¹H NMR results showed that more hydrogen bonds were formed between E-AM/AMPS molecular groups and molecular chains, which led to a cross-linked network structure of E-AM/AMPS which was observed by TEM. It was this cross-linked network structure that made E-AM/AMPS have a high viscosity and allowed it to be better adsorbed on bentonite particles, thus exhibiting excellent rheological and filtration behavior. In addition, E-AM/AMPS powder had a high specific surface area so that it can be dissolved in water faster, greatly reducing the time and difficulty of configuring drilling fluid.
... Recently, studies have explored the addition of Al 2 O 3 , MgO, TiO 2 , Fe 2 O 3 , SiO 2 , among other nanoparticles to improve the properties of the drilling fluids such as rheology [19][20][21][22][23], thermal and electrical conductivity [24,25], swelling shale inhibition [26][27][28], and filtration control [29][30][31][32][33]. ...
Although the application of nanoparticles in drilling fluid has been reported under static test by our research group, understanding inhibition formation of damage by filtration volume reduction in porous media under dynamic conditions is still a crucial issue. In this research, synthesised silica nanoparticles modified with acid treatment (Si11A) evaluated in previous results in the bentonite-free water-based drilling fluid (BFWBM) in static tests were analysed in the coreflooding test under dynamic and reservoir conditions. Si11A nanoparticles were evaluated by permeability return tests under reservoir conditions overburden, pore, and overbalance pressures, and temperatures of 3000 psi, 1700 psi, 1200 psi, and 87 °C, respectively. Coreflooding test with a concentration of 0.1 wt% Si11A nanoparticles based on our previous work showed a reduction in the filtration volume by 77%, decreasing the formation damage by 51% compared to the drilling fluid without nanoparticles. Also, the oil recovery obtained with the best design fluid using the Si11A nanoparticles was 10% higher than the baseline. Additionally, the effluents of crude oil obtained from permeability return test were evaluated at reservoir temperature using a rotational rheometer at shear rates varying between 1 and 100 s−1, obtaining a reduction of the viscosity up to 28% during nine pore volume injected using the BFWBM with S11A nanoparticles. The role of the nanoparticles in the drilling fluid is the rapid deposition in the mudcake to enhance the properties, the subsequent filtration volume reduction, and the enhancement of the petrophysics properties may be described by dynamic filtration curves, effective oil permeability and relative permeability curves.
... Several types of research have been done on the use of nanoparticles and nanostructures such as polymeric, non-polymeric and metal oxide nanoparticles as well as different carbon nanostructures like carbon nanotubes and graphene to improve drilling mud properties (Hoelscher et al., 2013). For example, the addition of different metal oxide nanoparticles such as TiO 2 , SiO 2 , Al 2 O 3 , CuO, ZnO, and ZnTiO 3 , and also various metal borate to the drilling mud would improve its filtration rate (Vryzas and Kelessidis, 2017;Kusrini et al., 2018;Perween et al., 2018;Vryzas et al., 2019;Saffari et al., 2018). Furthermore, by the presence of these nanoparticles in drilling fluid, the apparent viscosity (AV), plastic viscosity (PV) and yield point (YP) are increased (Perween et al., 2018;Bayat et al., 2018;Dejtaradon, 2019). ...
Drilling fluid loss is one of the basic problems in the drilling industry, which includes 10 to 20 percent of the cost of a drilling operation. It can cause some complications, such as creation of the water in oil emulsion. Furthermore, the presence of toxic hydrogen sulfide (H2S) gas in the excavation formations and the risk of its transfer to the surface, is a hazard to the health of employees on drilling rigs and causes corrosion of surface and subsurface equipment. In this study, the effect of adding Graphene Oxide-Zinc Oxide (GO-ZnO) nanocomposite on the drilling fluid properties and H2S removal were investigated. First, the GO-ZnO nanocomposite was synthesized. After XRD, SEM and EDS characterization tests and assuring the formation of the nanocomposite, drilling fluid samples were prepared by adding different concentrations of GO-ZnO nanocomposite to the base fluid (used in a real reservoir). Then the rheology, filtration, and gas chromatography tests were performed on various fluid samples. The results indicated desirable increases in the rheological properties such as plastic viscosity (5%–28%), yield point (25%–42%) and gel strength (25%–33%) and a significant decrease in the filtration rate. Besides, the results of the chromatographic tests indicated the ability of GO-ZnO nanocomposite to entirely remove the H2S in 15 min.
... For bentonite-based drilling fluid, the rheological and filtration properties can be improved by using chitin nanocrystals from speckled swimming crab shell waste at different ranges of pH [1] or by adding cellulose nanocrystals, especially in the case of low solid content of bentonite-water-based drilling fluid [2]. In addition, Wyoming sodium bentonite-water-based drilling drilling fluid has better suspension and filtration control properties when mixing nanoparticles with bentonite particles in different configurations [3]. ...
Barite sag is a serious problem encountered while drilling high-pressure/high-temperature (HPHT) wells. It occurs when barite particles separate from the base fluid leading to variations in drilling fluid density that may cause a serious well control issue. However, it occurs in vertical and inclined wells under both static and dynamic conditions. This study introduces a combined barite–ilmenite weighting material to prevent the barite sag problem in water-based drilling fluid. Different drilling fluid samples were prepared by adding different percentages of ilmenite (25, 50, and 75 wt.% from the total weight of the weighting agent) to the base drilling fluid (barite-weighted). Sag tendency of the drilling fluid samples was evaluated under static and dynamic conditions to determine the optimum concentration of ilmenite which was required to prevent the sag issue. A static sag test was conducted under both vertical and inclined conditions. The effect of adding ilmenite to the drilling fluid was evaluated by measuring fluid density and pH at room temperature, and rheological properties at 120 °F and 250 °F. Moreover, a filtration test was performed at 250 °F to study the impact of adding ilmenite on the drilling fluid filtration performance and sealing properties of the formed filter cake. The results of this study showed that adding ilmenite to barite-weighted drilling fluid increased fluid density and slightly reduced the pH within the acceptable pH range (9–11). Ilmenite maintained the rheology of the drilling fluid with a minimal drop in rheological properties due to the HPHT conditions, while a significant drop was observed for the base fluid (without ilmenite). Adding ilmenite to the base drilling fluid significantly reduced sag factor and 50 wt.% ilmenite was adequate to prevent solids sag in both dynamic and static conditions with sag factors of 0.33 and 0.51, respectively. Moreover, HPHT filtration results showed that adding ilmenite had no impact on filtration performance of the drilling fluid. The findings of this study show that the combined barite–ilmenite weighting material can be a good solution to prevent solids sag issues in water-based fluids; thus, drilling HPHT wells with such fluids would be safe and effective.
Sustainable wastewater treatment methods are very important and necessary because they help to protect the environment and the health of humans, animals and other living organisms. With the increase in industries and population, toxic dyes produced in various industries have created a serious issue for public health and the main concern of environmental protection. This method affects the quality of purified water and causes various diseases, and as a result, it ends in death. Water purification is very important and plays an important role in the environment. Pollutant removal has different methods that include physicochemical and biological treatment. Each of these methods shows different pollutant removal capabilities that are studied here, depending on the experimental limitations. Among the different methods of wastewater treatment, the methods that have a high cost are not used today, and the results have shown that researchers consider more in the fields that have a low cost of material and testing. Surface adsorption is considered the most efficient method due to its high removal efficiency, easy operation, cost-effectiveness and recyclability of adsorbents. In this paper, the sustainable applications of wastewater treatment for the removal of colored pollutants have been investigated. Here, chitin and chitosan are more commonly used nowadays due to the naturalness of the polymer material, and it is not toxic and has many uses in various fields that can be used by adsorption. In this context, this work aims to provide a comprehensive summary of the adsorption of dyes from wastewater by nano-biopolymers, especially chitin and chitosan, as adsorbents. First, a summary of biopolymers, the properties of chitin and chitosan and synthesis techniques are presented. After the classification of dyes, the techniques for removing them from the wastewater are described. In addition, the adsorption process and isotherms used for adsorption are described with different models. Among various adsorbents, such as carbon materials, metals/metal oxides and zeolites, nano-biopolymers, especially chitin and chitosan, are the most promising ones for environmental sustainability. The results show that the use of biocompatible biopolymers to remove dye pollutants in different dyeing and textile industries plays an important role in determining the sustainable methods of wastewater treatment and can reduce the environmental effects of industries. Surface adsorption can be compatible with the environment and remove various colored pollutants well so that we have clean and pollution-free water and can use water.
A special type of two-dimensional (2D) material based conducting polymer was constructed by green synthesis and in-situ polymerization techniques. The 2D Molybdenum Disulfide (MoS2) were first synthesized with the combination of, ammonium tetrathiomolybdate dissolved in 20 mL algae extract under stirring. After stirring for about 2 h, and then finally sulfurization was initiated using sulfur powder in 20 mL of sulfuric solution and stirred for 8 h. The resulting black precipitates of MoS2 were collected by centrifugation at 5000 rpm. Moreover, the prepared MoS2 was functionalized with glycidyl methacrylate (GMA) and form the MoS2@PGMA. Further, the MoS2@PGMA is combined with polyaniline (PANI) to form conducting polymer grafted thin film nanosheets named MoS2@PGMA/PANI with a thickness in micrometer size through grafting method. The prepared materials were characterized by SEM, FTIR, XRD, XPS and EDX techniques. To check the performance of materials the adsorption study was performed. Moreover, the adsorption study toward Cu2+ and Cd2+ showed a tremendous results and the maximum adsorption was 307.7 mg/g and 214.7 mg/g respectively. In addition, the pseudo-first and second order models as well as the adsorption isotherm were investigated using the Langmuir and Freundlich model. The results were best fitted with the pseudo-second order and Langmuir models. The regeneration study was also conducted and MoS2@PGMA/PANI nanosheets can be easily recycled and restored after five successful recycling. The established methodology for preparing the 2D materials and conducting polymer based MoS2@PGMA/PANI nanosheets is expected to be applicable for other multiple applications.
Current energy demand and environmental pollution issues are growing due to global urbanization and development in many countries, leading to amplified energy/material consumption, serious and irreparable damage to the ecosystem with simultaneous waste formation. The world energy demand is mainly accomplished by finite fossil fuel-based reserves, which have a crucial impact on the ecosystem/environment, and consequently, there is a need for a sustainable and/or low-carbon bioeconomy. Hydrogen (H2) generation from renewable biomass/waste is a promising bioenergy system that can generate low-carbon hydrogen and reduce GHG (greenhouse gas) emissions by 2050. Waste-to-biohydrogen (WtBH) can become a portion of the zero-emissions fuel replacement for natural gas and serve as one of the sustainable cleaner hydrogen sources which are environmentally friendly and economically feasible. In this view, bio-H2 is considered appropriate because of its high potential as a green, clean, and sustainable carbon-neutral energy source in the emerging low-carbon hydrogen bioeconomy. Nanostructured systems based on renewable biomass/waste sources depict a high potential to produce sustainable and low carbon biohydrogen economy because of their excellent physicochemical structures, such as high efficiency, high surface/volume ratio, non/low-toxicity, high chemical/mechanical stability, biodegradability/biocompatibility, availability, sustainability, cost-effectiveness, and unusual electrical/mechanical and magnetic properties. Renewable biomass and waste materials are extensively considered green sources to prepare greener and more sustainable sorts of mono- or bi-metallic nanomaterials using facile approaches. This review summarizes the deployment of thermochemical and biochemical approaches for WtBH using nanobiocatalysts towards a low-carbon bioeconomy.
Graphical Abstract
The greatest environmental issue of the twenty-first century is climate change. Human-caused greenhouse gas emissions are increasing the frequency of extreme weather. Carbon dioxide (CO2) accounts for 80% of human greenhouse gas emissions. However, CO2 emissions and global temperature have risen steadily from pre-industrial times. Emissions data are crucial for most carbon emission policymaking and goal-setting. Sustainable and carbon-neutral sources must be used to create green energy and fossil-based alternatives to reduce our reliance on fossil fuels. Near-real-time monitoring of carbon emissions is a critical national concern and cutting-edge science. This review article provides an overview of the many carbon accounting systems that are now in use and are based on an annual time frame. The primary emphasis of the study is on the recently created carbon emission and eliminating sources and technology, as well as the current application trends for carbon neutrality. We also propose a framework for the most advanced naturally available carbon neutral accounting sources capable of being implemented on a large scale. Forming relevant data and procedures will help the "carbon neutrality" plan decision-making process. The formation of pertinent data and methodologies will give robust database support to the decision-making process for the "carbon neutrality" plan for the globe. In conclusion, this article offers some opinions, opportunities, challenges and future perspectives related to carbon neutrality and carbon emission monitoring and eliminating resources and technologies.
Background
An efficient solution to the global freshwater dilemma is desalination. MXene, Molybdenum Disulfide (MoS2), Graphene Oxide, Hexagonal Boron Nitride, and Phosphorene are just a few examples of two-dimensional (2D) materials that have shown considerable promise in the development of 2D materials for water desalination. However, other promising materials for desalinating water are biomaterials. The benefits of bio-materials are their wide distribution, lack of toxicity, and superior capacity for water desalination.
Methods
For the rational use of water and the advancement of sustainable development, it is of the utmost importance to research 2D-dimensional materials and biomaterials that are effective for water desalination. The scientific community has concentrated on wastewater remediation using bio-derived materials, such as nanocellulose, chitosan, bio-char, bark, and activated charcoal generated from plant sources, among the various endeavors to enhance access to clean water. Moreover, the 2D-materials and biomaterials may have ushered in a new age in the production of desalination materials and created a promising future.
Results
and conclusions The present review article focuses on and reviews the progress of 2D materials and biomaterials for water desalination. Their properties, surface, and structure, combined with water desalination applications, are highlighted. Further, the practicability and potential future directions of 2D materials and biomaterials are proposed. Thus, the current work provides information and discernments for developing novel 2D materials and biomaterials for wastewater desalination. Moreover, it aims to promote the contribution and advancement of materials for water desalination, fabrication, and industrial production.
Today, it is known that most of the water sources in the world are either drying out or contaminated. With the increasing population, the water demand is increasing drastically almost in every sector each year, which makes processes like water treatment and desalination one of the most critical environmental subjects of the future. Therefore, developing energy-efficient and faster methods are a must for the industry. Using functional groups on the membranes is known to be an effective way to develop shorter routes for water treatment. Accordingly, a review of nano-porous structures having functional groups used or designed for desalination and water treatment is presented in this study. A systematic scan has been conducted in the literature for the studies performed by molecular dynamics simulations. The selected studies have been classified according to membrane geometry, actuation mechanism, functionalized groups, and contaminant materials. Permeability, rejection rate, pressure, and temperature ranges are compiled for all of the studies examined. It has been observed that the pore size of a well-designed membrane should be small enough to reject contaminant molecules, atoms, or ions but wide enough to allow high water permeation. Adding functional groups to membranes is observed to affect the permeability and the rejection rate. In general, hydrophilic functional groups around the pores increase membrane permeability. In contrast, hydrophobic ones decrease the permeability. Besides affecting water permeation, the usage of charged functional groups mainly affects the rejection rate of ions and charged molecules.
The increasing exploration of oil/gas resources in unconventional reservoirs, such as deep layers and shale formation, hinges on the development of high-performance drilling fluids under harsh environments. In this work, self-crosslinkable nanoparticles [poly(methyl methacrylate/styrene/2-acrylamido-2-methyl-1-propanesulfonic acid (PMS)/N-(hydroxymethyl)acrylamides (PMSNs)] were prepared and utilized as a plugging agent to realize micropore plugging at high temperatures. The obtained PMSN possesses long-term colloidal stability in conventional storage and high-temperature aging cases. Incorporating thermal crosslinking property brought PMSN post-crosslinking behavior during thermal treatment and improved the thermal stability, as verified by Fourier transform infrared spectrometer (FT-IR) and thermogravimetric analysis (TGA) tests. Additionally, PMSN is emulsifier-free and compatible with bentonite-based drilling fluid without foaming problems. Compared with conventional rigid nanosilica (NS) and flexible nanopolyester (NP-1), PMSN can improve the hole-cleaning efficiency of sodium bentonite (Na-Bent) dispersion by increasing viscosity and yield point (YP), especially after thermal aging. Its filtration-reduction and clay core plugging performance at room temperature are between NS and NP-1, ascribing to the rigid core and partial flexible shell structures of PMSN. However, at high-temperature, high-pressure (HTHP) conditions, PMSN with self-crosslinked structures have superior micropore plugging performance over NS and NP-1. A statistical-significant model was established based on response surface methodology (RSM) to illustrate the main and interactive effects of PMSN dosage, aging temperature, and time on the HTHP micropore fluid loss. The optimal plugging can be obtained after high-temperature aging when self-crosslinking happened. The specific self-crosslinking plugging mechanism of PMSN is the combination of interior self-crosslinking in water and interparticle crosslinking in the deposited plugging layer.
Insufficient foam stability hinders the applications of the foam injection technique for enhanced oil recovery. To date, to improve foam stability, nanoparticles have been synergistically used with surfactants. Thus, evaluating the interactions between nanoparticles and surfactants is essential to understand and improve foam stability. In a surfactant solution involving nanoparticle dispersions, nanoparticles and ionic surfactants possess net surface charges that lead to electrostatic interaction-induced adsorption of surfactant molecules on nanoparticles. The adsorption of surfactants on nanoparticles changes their surface wettability, leading to their migration to the bubble-fluid interface formed by the foam. In this work, silica nanoparticles with different surface characteristics were used in conjunction with alpha olefin sulfonate as a surfactant to stabilize natural gas foams. The incorporation of nanoparticles to natural gas foams improved surfactant performance by 70%. Besides, nanoparticle-surfactant interactions were analyzed through adsorption experiments to provide insights into the effects of nanomaterials on the stability of natural gas foams. The adsorption of the surfactant is higher on silica nanoparticles that exhibit the lowest acidic surface and surface charge in comparison with the evaluated nanomaterials, which substantially affect electrostatic interaction-driven surfactant adsorption on the nanoparticles. The foam stability tests showed that the surfactant/nanoparticle ratio is critical to improving foam stability for each nanomaterial, because high surfactant adsorption can decrease the foam stability. For materials with higher adsorption affinity, to obtain highly stable foams, the amount of nanoparticles was reduced by 50% compared with the materials with lower adsorption affinity. The optimal surfactant/nanoparticle ratio with the lowest nanoparticle amount, which led to the most stable foam obtained, was evaluated at reservoir conditions in a natural gas core flooding test. The results showed an 18% increase in oil recovery in the presence of surfactant solutions with nanoparticles, indicating mitigation of gas injection drawbacks due to the blockage of preferential channels.
One of the main damage mechanisms identified in the Ocelote field is the drilling-induced formation damage during drilling operations. The productivity of a well during its production life decreases because of fines migration and changes in the wettability due to organic deposits. In this study, we designed a double purpose nanofluid to reduce the drilling-induced formation damage while the invaded mud filtrate enhances the mobility of the crude oil and migration fines control. The nanoparticles (NPs) used were fumed silica and commercial alumina. The effectiveness of the nanoparticles in improving the rheological and filtration properties of the drilling fluid was assessed by conducting rheological and filtration tests under high pressure–high temperature (HPHT) conditions in terms of the NP concentration after the hot rolling process. The experimental results in terms of the plastic viscosity, yield point, and gel strength showed that as the NP concentration increases, the values of the rheological parameters increase, with the Si NPs exhibiting the best performance. Regarding the filtration properties, the Si and Al NPs reduced the filtration volume by 17%, with the Si nanoparticles presenting the highest reduction in the mudcake thickness of 6%. At NP concentrations above 0.3 wt.%, the filtration reduction effect decreases. Therefore, the mud filtrate obtained from the HPHT filtration test conducted on a drilling fluid with an NP concentration of 0.05 wt.% was used to evaluate the mud filtrate quality to improve the mobility of the crude oil by interfacial tension (IFT) reduction and the capacity to alter the oil-wet to water-wet surface. The retention of the fine particles in impregnated Ottawa sand was tested through a break–rupture curve. The results showed that the mud filtrate with Al NPs could decrease the IFT between the intermediate heavy crude (23°API) and the mud filtrate by more than 24% and could alter the contact angle from approximately 66 to 41 °C. Additionally, the core treated with the mud filtrate with Al NPs imbibed twice the mass in 2 h, more than the core treated with the mud filtrate in the absence of NPs. Hence, the Si NPs did not present significant changes in the IFT and wettability alteration but increased the retention of the fine particles in the treated sand. The Al NPs helped reduce the filtration volume, presented a marked impact on the wettability alteration to preferential water-wet, reduced the IFT, and to some extent aided fines migration control; therefore, the Al NPs were selected for the evaluation in displacement tests on rock samples under dynamic and reservoir conditions. Additionally, the drilling fluid with the Al NPs reduced the dynamic filtration volume by 45% with a subsequent reduction in the formation damage by 20% and increase in the critical flow of migratory clays by 66% in comparison with the drilling fluid without NPs. Finally, the residual water saturation was reduced, and the crossover point between the relative permeability curves shifted to the right. Finally, technical studies for field applications will be carried out, where two twin wells with similar properties will be drilled, allowing for a comparative analysis of the application of NPs to drilling fluids with the same formulation in terms of the invasion diameter, well stabilization time, productivity index, and solid production.
Ionic liquids are well-liked drilling fluid additives for inhibiting hydrates and modifying mud rheology. However, preparation of ionic liquid is costly and imidazolium based ionic liquids have been found to be severely toxic. Deep Eutectic Solvent (DES) is a non-toxic and cheaper alternative of traditional ionic liquids. In this research, in-house prepared, Choline chloride and Urea based DES has been used as a drilling fluid additive in water based mud. Micro-DSC has been used to study the induction time of methane gas hydrates at 114 bar between −20 °C to 20 °C. Drilling fluid rheology and properties have been determined by following AP1 13B-1 standards. The results of Micro DSC evidenced that the addition of DES delayed the induction time of the hydrates up to 24.3%, improved the YP/PV of the drilling fluid and also resulted into 20% and 14.5% reduction in filtrate volume and mud cake thickness respectively. Moreover, based upon the outcomes of characterizations i.e. Zeta potential, XRD and FTIR, it is proposed that the improvement in mud rheology is due to the change in clay's size and structure on interaction with DES. Consequently, the DES inhibits the hydrate formation and alters the mud rheology by its excellent ability to form hydrogen bonds with hydrates' crystals and clay granules respectively.
Актуальность исследования связана с необходимостью увеличения успешности буровых работ за счёт применения высокоэффективных и экономически рентабельных добавок для создания буровых растворов с улучшенными свойствами. В настоящее время различные наночастицы, благодаря их уникальным физическим свойствам, активно используются во многих отраслях промышленности. За счёт своей высокой удельной поверхности и размера наноматериалы являются хорошими кандидатами для улучшения фильтрационных и реологических свойств бурового раствора. Однако при исследовании возможности применения наноматериалов в качестве добавки к буровому раствору необходимо учитывать их стоимость как один из наиболее важных факторов. Цель: исследовать влияние наноразмерного диоксида кремния и графена на фильтрационные и реологические свойства бурового раствора в стандартных и пластовых условиях; оценить фактическую стоимость бурового раствора с добавлением наночастиц; провести сравнительный анализ технических и экономических характеристик исследуемых растворов с добавлением наноматериалов и промышленного бурового раствора. Объект: буровые растворы на водной основе. Методы: лабораторные исследования фильтрационных и реологических свойств буровых растворов на водной основе. Результаты. Полученные результаты демонстрируют улучшение реологических и фильтрационных свойств бурового раствора при добавлении наноматериалов. С увеличением концентрации наночастиц происходит постепенное снижение водоотдачи. Образец с самой высокой концентрацией наноразмерного диоксида кремния по сравнению с базовой жидкостью показал уменьшение объема фильтрата в стандартных и пластовых условиях на 72,2 и 61,1 %, соответственно, относительно промышленного бурового раствора с добавлением полианионной низковязкой целлюлозы снижение составило 34,1 и 27,3 %. Исследуемые растворы с добавлением графена демонстрируют сравнимую реологию, но имеют большие объемы потерь жидкости в сравнении с промышленным раствором с полианионной целлюлозой низкой вязкости. Проведенная экономическая оценка показывает, что добавление наноматериалов к буровому раствору даже в минимальных концентрациях приводит к чрезвычайному увеличению его фактической стоимости. Стоимость буровых растворов с наноразмерным диоксидом кремния или графеном в два–три раза выше, чем у базового и промышленного бурового раствора с полианионной целлюлозой низкой вязкости, что делает их использование экономически нецелесообразным.
The relevance of this study is caused by the need for high-performance and economically viable additives to formulate drilling fluids with desirable properties for successfully conducting a drilling operation. Nanomaterials have found their applications as very unique, sensitive materials in different industries due to their tiny size and exceptionally high surface area to volume ratio. Owing to these characteristics,
nanomaterials can be good candidates for improving drilling fluid performance with respect to filtration and rheological properties. However, cost as one of the most influential factors in decision-making on the selection of drilling fluid additive must be considered in the investigation of nanomaterials for practical application in drilling fluid.
The main aim of this research is to evaluate the influence of two nanomaterials at four different concentrations (1 to 4 kg/m3), graphene
nanoplates and silica nanoparticles, on the filtration properties under low pressure – low temperature and high pressure – high temperature conditions, rheological behavior, and actual cost of a field-applicable water-based drilling fluid. Besides, the technical performance and financial impact of the studied nanomaterials were compared with that of commercial additive commonly used in drilling fluids.
Object: technical performance and financial impact of graphene nanoplates and silica nanoparticles in a field-applicable drilling fluid.
Methods. Experimental investigation was performed in drilling fluid laboratory to determine filtration properties and rheological characteristics under low pressure – low temperature and high pressure – high temperature conditions.
Results. The experimental outcomes obtained in this study demonstrated that both the rheological and the filtration properties of the drilling fluid system were improved in the presence of nanomaterials. For both conditions, filtration was reduced with an incremental increase of nanosilica and graphene nanoplates in the base fluid system. Where the sample with the highest concentration of nanosilica (4 kg/m3) demonstrated under low pressure – low temperature conditions – 72,2 and at high pressure – high temperature conditions – 61,1 % reduction in the volume of the filtrates when compared to the base fluid. The studied nanofluid systems with graphene nanoplates presented comparable rheology but greater fluid loss volume in compassion to that of the low-viscosity polyanionic cellulose containing fluid. As for the nanofluids containing nanosilica, the obtained results displayed only the nanofluid sample with 4 kg/m3 outperformed the field applicable fluid containing low-viscosity polyanionic cellulose in terms of filtration by showing 34,1 and 27,3 % less fluid loss for low pressure – low temperature and high pressure – high temperature conditions respectively. The financial impact assessment provided demonstrated that the introduction of nanomaterials resulted in the enormously high actual cost, where the nanofluids cost with only 1 kg/m3 nanographene or nanosilica was approximately two to three times higher than those of the base fluid and low-viscosity polyanionic cellulose containing fluid. The results of the study revealed that the huge cost of the studied nanomaterials is their major disadvantage, hindering them from practical application in drilling fluids industry.
Extended reach (ERD) wells with a horizontal and highly deviated section are commonly utilized in deep oil and natural gas exploration operations. Among many difficulties faced in this complex wellbore trajectory, good hole cleaning is one of the biggest challenges. The main objective of the present study is to investigate the application of cellulose nanoparticles (CNPs) in improving hole cleaning in horizontal drilling operations. Nanocomposite drilling fluids were prepared by adding CNPs, including cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs), into water-based mud (WBM) at different weight percent concentrations (0.15–0.60 wt%). The flow loop experiments were implemented on a sophisticated purpose-built flow rig by circulating the tested fluid samples into the test section in a horizontal position, considering the influence of drill pipe rotation, flow rates, cuttings sizes, and drill pipe eccentricity. The goal of such variation in the operational parameters is to simulate real field conditions. The cuttings transport ratio (CTR) which is defined as the ratio of the weight of recovered cuttings to the weight of injected cuttings is chosen as the measurement to evaluate hole cleaning. The results revealed that the nanocomposite drilling fluids displayed a considerable enhancement in cuttings removal efficiency, especially with the higher concentration of CNPs. The morphology of CNPs played a vital role in improving the rheological properties of the water-based drilling fluids. In comparison, the drilling fluid samples with CNCs had comparatively lower cuttings transports ratio (CTR) than these of the fluids with CNFs. These differences were connected to their distinguished morphologies and different interactions with bentonite in the fluid system. This work is the first attempt to evaluate the applications of renewable, biodegradable, environmentally friendly, and more cost-effective nanoparticle additives to enhance the capability of drilling fluids in transporting and circulating drilled cuttings out of the wellbore.
The approaching era of sustainable development and rapid increase in global energy demand necessitate the development of high-performance drilling fluids with low-toxicity, sustainability, and in-situ rheology controllability for complicated formation excavation. Herein, smart water-based drilling fluids (WDFs) with thermo-controllable rheological properties are developed using bentonite (BT) and dual-functionalized cellulose nanocrystals (fCNCs). The fCNCs are synthesized by surface grafting of poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) and poly (N-isopropylacrylamide) (PNIPAM) through free radical graft polymerization. The presence of PAMPS grafts with abundant amide and negatively charged sulfonate groups not only enable fCNCs to attach on the surface of BT platelets, creating BT/fCNC clusters; but also ensure the created BT/fCNC clusters to uniformly disperse through electrostatic repulsion. On the other hand, the introduction of thermo-responsive PNIPAM grafts induce the association of BT/fCNC clusters at elevated temperatures through enhanced hydrophobic attraction, resulting in promising thermo-thickening rheological performance of BT/fCNC-WDFs. Furthermore, the thermo-thickening rheological behavior can be maintained even after 10 heating/cooling cycles, albeit with a slight increase in the critical transition temperature. The developed BT/fCNC-WDFs with sustainability, in-situ rheology controllability, and good cyclability have great potential in smart drilling industry, making the exploration and production of oil and gas more safe, efficient and environmentally friendly.
Drilling in alpine ecological fragile areas for the energy and mineral exploration needs superior low temperature drilling fluids with the required environmental protection of the ecosystem and a high efficiency of core drilling. To meet this demand, a comprehensive study on the appropriate material sourcing, lab measured properties and mechanism analysis of a new drilling fluid suitable for such areas was conducted by a systematic method of theoretical analysis, experimental work and a verifying field test. As a result, a new low temperature vegetable gum drilling fluid (NCKL) was developed by mixing with kuli vegetable gum, antifreeze potassium formate, nano silica, polymer synergist, and inorganic treatment agent. Lab test results showed that NCKL had an easy preparation, good low temperature rheology, viscoelasticity, anti-collapse property, and exceeding environmental protection level requirement (as per LC50 test). An analysis of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy were used to investigate the microscopic features of NCKL, which led to a low temperature mechanism explanation. Finally a successful field test demonstrated that NCKL provided a new potential solution for a better core drilling in complex strata of alpine ecological fragile areas.
One of the important functions of drilling fluids is to form a filter cake, which minimizes leakoff of drilling fluids into the formation. Drilling-fluid invasion can cause formation damage, but good-quality filter cake can reduce such damage. This research focuses on the laboratory techniques and performance results of testing innovative calcium-bentonite-based drilling fluids containing nanoparticles (NPs) for minimizing formation damage during drilling in harsh environments.
A rotational viscometer was used to measure the rheological properties of the tested fluids. Zeta-potential measurements were conducted at different NP concentrations to assess their stability and to investigate the role of charge potential. Indiana limestone outcrop disks were examined as the filter media for both static and dynamic filtration (up to 350°F and 500 psi) using a filter press. The filter cakes were examined using a computed-tomography (CT) scan and scanning-electron-microscopy energy-dispersive spectroscopy (SEM-EDS). Inductively coupled plasma optical-emission spectrometry (ICP-OES) was used to measure the concentrations of key ions in the filtrate fluids. A reduction of 43% in the filtrate-fluid volume was achieved when adding 0.5 wt% of ferric oxide NPs compared with that of the base fluid. However, using silica NPs led to an increase in the filtrate volume and filter-cake thickness. Using 0.5 wt% of ferric oxide NPs provided less agglomeration and reduced the filter-cake permeability. In addition, the SEM-EDS and ICP-OES analysis showed a replacement of the cations dissociated from the bentonite by NPs, which promoted the formation of a rigid clay-platelet structure. The produced filter cakes consisted of two layers, as indicated by the CT-scan analysis. Increasing the concentration of NPs resulted in an increase in the fluid loss and filter-cake thickness. At a higher NP concentration (2.5 wt%), a third layer of NPs was observed, which adversely affected the filter-cake characteristics, as demonstrated by CT-scan analysis and SEM-EDS elemental mapping. Furthermore, the NP-bentonite fluids had stable rheological properties at different temperatures (up to 200°F) and NP concentrations. In addition, aging these fluids at 350°F for 16 hours showed minor changes in the rheological properties.
This research work provides an experimental evaluation of improved calcium-bentonite-based fluids using NPs under downhole conditions. The ferric oxide NPs have the potential to enhance the properties of calcium bentonite, as a low-cost alternative, to perform well in an application where the higher-value sodium bentonite is commonly used, which could provide more-efficient drilling operations and less formation damage.
Commercial hematite (Fe2O3) and magnetite (Fe3O4) nanoparticles (NPs) had been used as additives to develop smart drilling fluids. Both types of NPs were found to enhance the properties of such fluids. This work focuses on using a custom-made (CM) magnetite (Fe3O4) NPs to improve the properties of bentonite-based fluids. The microstructure qualities and mode of interaction have indentified, which help in optimizing the rheological and fluid loss properties of drilling fluids.
Rheological properties of the tested fluids were measured using a rotational viscometer at different temperatures up to 60°C (140°F) and atmospheric pressure. Step-change shear rate measurements revealed the degree of thixotropy of the produced suspensions. Fluid loss characteristics were examined under 20.7 bar (300 psi) and 121°C (250°F). Both rheological and fluid loss measurements were also conducted using fluids that are thermally aged at 177°C (350°F) for 16 hrs. Filter cake surface morphology was evaluated using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). Bentonite composition was examined by X-ray diffraction (XRD) and X-ray fluorescence (XRF). A superconducting quantum interference device (SQUID) magnetometer was used to measure the magnetic properties of the CM Fe3O4 NPs, and their size was determined using transmission electron microscopy (TEM).
The CM Fe3O4 NPs, which were synthesized by co-precipitation method, have average diameter of 6-8 nm, as indicated by TEM. Magnetic measurements revealed their superparamagnetic behaviour with saturation magnetization of 60 emu/g. For all the tested samples, the Herschel-Bulkley (HB) model was determined to be the best fit model with good correlation coefficient (R2 > 0.99). Yield stress, viscosity, and gel strength of the tested fluids showed significant improvement when adding the CM Fe3O4NPs, which could be a result of the rigid network formed. A linear dependence of yield stress on temperature of the produced nanofluids (NF) was identified. Adding the CM Fe3O4 NPs at 0.5 wt% showed optimal rheological and filtration characteristics. Dynamic thermal aging adversely affects the properties of base fluid. However, the NF maintained its extraordinary rheological and filtration behavior. SEM-EDS analysis revealed the microstructure of the produced filter cake.
The better performance of the CM Fe3O4 NPs can be attributed to their extremely small size, which confer stability in suspensions and effective linking with the bentonite particles, thus allowing the formation of a rigid microstructure network. Such approach introduces the synergistic interaction of components to produce a water-based drilling fluid system with excellent fluid loss characteristics and optimal rheological properties for HP/HT applicaltions.
Access to deeper oil and gas reservoirs in hostile environments necessitates improvement of existing drilling fluids. This work focuses on the lab techniques for developing, assessing and analyzing innovative water-based drilling fluids containing iron oxide (Fe2O3) and silica nanoparticles (SiO2).
The fluid loss characteristics were examined both in an American Petroleum Institute (API) static filter press and in a High Temperature-High Pressure (HTHP) filter press under elevated pressures and temperatures (300 psi/250°F). A computed-tomography (CT) scan was used for deep analysis of the filter cake. Scanning Electron Microscopy (SEM) was used to analyze the morphology of the filter cake as well as to give deep insights for their microstructure, the interfacial phenomena and the interaction between bentonite particles and the nanoparticles. Inductively Coupled Plasma (ICP) mass spectrometry was used to determine the quality of the produced filtrate. Zeta potential measurements were used to assess the stability of the developed suspensions. The changes in the rheological properties of the nanofluids were measured at HT conditions using a standard Fann type viscometer.
Significant modifications have been observed with the addition of nanoparticles to the base fluid of water-bentonite suspension in rheological and filtration characteristics. The rheological analysis showed an increase of the yield stress and of the gel strength as the concentration of nanoparticles was increased. Both the API static and the HTHP filter press indicated a remarkable improvement in the fluid loss and filter cake characteristics for the samples containing iron oxide nanoparticles. For samples containing silica nanopowder, there was an adverse effect on the fluid loss characteristics with minor changes in the rheological profile.
The filtration efficiency was reduced with the increase of the concentration of Fe2O3 nanoparticles which was confirmed by CT scan measurements. Results revealed that 0.5% (w/w) is the optimal concentration for the Fe2O3 nanoparticles, above which they form a new layer in the filter cake that adversely affected the fluid loss and filter cake characteristics. SEM and ICP measurements confirmed this phenomenon and revealed the agglomeration effect and the smooth surface of the produced filter cakes. Zeta potential measurements at different concentrations and temperatures of the produced nanofluids showed that the iron oxide nanoparticles were stable in colloidal suspensions, whereas silica nanopowder was unstable under different temperatures.
The examined nanoparticles have the potential to significantly improve the characteristics of the filter cakes at both low temperature-low pressure (LTLP) and HTHP conditions. They also have the ability to maintain optimal rheological properties so that many drilling problems can be efficiently mitigated. Their low concentration in the drilling system, compared to other conventional drilling additives, provides a basis for more efficient drilling practices.
A successful drilling operation requires an effective drilling fluid system. Due to the variety of downhole conditions across the globe, the fluid system should be designed to meet complex challenges such as High-Pressure/High-Temperature (HPHT) environments, while promoting better productivity with a minimum interference for completion operations. This study aims to improve the rheological and fluid loss properties of water-bentonite suspensions by using both commercial (C-NP) and custom-made (CM-NP) iron oxide (Fe3O4) nanoparticles (NP) as drilling fluid additives.
Superparamagnetic Fe3O4 NP were synthesized by the co-precipitation method. Both types of nanoparticles were characterized by a High Resolution Transmission Electron Microscope (TEM) and X-ray Diffraction (XRD). Base fluid (BF), made of deionized water and bentonite at 7wt%, was prepared according to American Petroleum Institute (API) procedures and nanoparticles were added at 0.5wt%. A Couette-type viscometer was used to analyze the rheological characteristics of these fluids at different shear rates and various temperatures (up to 158°F). The rheological parameters were obtained from analysis of viscometric data using non-linear regression. The API Low-Pressure/Low-Temperature (LPLT) and HPHT fluid filtrate volumes were measured, using a standard API LPLT static filter press (100 psi, 77°F) and an API HPHT filter press (300 psi, 250°F). Observation of the porous matrix morphology of the produced filter cakes was done with Scanning Electron Microscope (SEM).
TEM showed that the mean diameter of the CM-NP was 7–8 nm, with measured surface areas between 100–250 m²/g. The C-NP had an average diameter of <50 nm, as per manufacturer specifications. The XRD of the CM-NP revealed peaks corresponding to pure crystallites of magnetite (Fe3O4) with no impurities. Rheological analysis showed very good fitting by the Herschel-Bulkley model with coefficient of determination (R²) greater than 0.99. Rheological properties of all samples were affected by higher temperatures, with increase in yield stress, decrease in flow consistency index (K) and slight increase in flow behavior index (n). Fluid filtration results indicated a decrease in the LPLT fluid loss and an increase in the filter cake thickness compared to the BF upon addition of higher concentrations of C-NP, because of a decrease in filter cake permeability. At HPHT conditions, samples with 0.5wt% C-NP had a smaller fluid loss by 34.3%, compared to 11.9% at LPLT conditions. CM-NP exhibited even higher reduction in the fluid loss at HPHT conditions of 40%.
Such drilling fluids can solve difficult drilling problems and aid in achieving the reservoir’s highest potential by eliminating the use of aggressive, potentially damaging chemicals. Exploitation of the synergistic interaction of the utilized components can produce a water-based system with excellent fluid loss characteristics while maintaining optimal rheological properties.
Copyright © 2016 by ASME Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
Background: Magnetic nanoparticles (NPs) used in biomedical applications should be discrete with small particle sizes, narrow size distribution and superparamagnetic. NPs can be tailored to target, through chemical bonds, specific organs, cells, or even molecular markers of different diseases in vivo, with suitable surface chemistry modification. Methods: Nanoparticles are synthesized by a low cost coprecipitation reaction of ferrous and ferric salts with alkaline solution. The characteristics of the NPs are modified by varying the addition rate of the alkaline solution. NPs surface is silica coated using a modified Stöbe method. The conversion of the surface hydroxyl groups into amino-groups is performed by two different alkoxysilanes and the silanization reaction is conducted either in Methanol – Glycerol environment at elevated temperature, or in water at room temperature. The surface amine groups of the NPs are further converted, either to aldehyde groups by glutaraldehyde, or to carboxyl groups using glutaric anhydride. Bovine Serum Albumin and Vena human natural immunoglobulin are used in order to study the protein conjugation capacity of the functionalized NPs. The amount of protein attached to the nanoparticles is determined by UV–Vis spectroscopy of the supernatant. Conjugation of synthesized nanoparticles to protein BSA is examined by FTIR spectroscopy. SDS-PAGE electrophoresis followed by protein immunoblotting is used to test the effect of nano-conjugation to the antibodies. Results: Superparamagnetic Fe3O4 nanoparticles with saturation magnetization 60emu/g, a mean diameter 8-12 nm and BET surface areas between 100-250 m2/gr are obtained with total time of addition of the base between 1-5 minutes. They are coated with a thin and nearly uniform silica (SiO2) layer with thickness 1-2 nm. The most appropriate source for surface functionalization with amino groups is 3-aminopropyltriethoxysilane (APTES), while the two silanization methods used, proved to be equally efficient. NPs with surface aldehyde groups display better conjugation capacity than NPs functionalized with carboxyl groups. The FTIR spectra of the protein conjugated NPs samples, contain the two main peaks, at 1529 cm-1 and 1661 cm-1, attributed to the amide bond of the protein, which confirms the conjugation of the protein to the NPs. During a SDS-PAGE electrophoresis -protein immunoblotting experiment, the antibodies, after being conjugated to the nanoparticles, are selectively attached to their antigen, which indicates of lack of significant conformation changes secondary to the conjugation process. Conclusion: The conjugation capacity of the optimized nanoparticles is higher for Ig antibody than for BSA protein, under similar reaction conditions. The conjugational efficacy and conformational stability and the effect on electrophoretic mobility of the antibodies conjugated to the nanoparticles are verified by protein immunoblotting.
Micro-nano-based drilling fluid has attracted a strong interest due to its attractive properties, and micro-nano composite materials have great potential for developing intelligent drilling fluid. In this study a novel hydrophobic associated polymer based nano-silica composite with core–shell structure was prepared and characterized by PSD, SEM, TEM and ESEM. The results showed that the composite, as a micro-nano drilling fluid additive, possessed excellent properties such as thermal stability, rheology, fluid loss and lubricity. Especially, it could plug the formation effectively and improve the pressure bearing capability of formation significantly.
A process is reported to obtain a nanoparticle sol from co-precipitated iron oxide particles without using any surfactant. The sol – a true ferrofluid – is not only stable over a wide range of pH but also in physiological solutions. This is a decisive step towards biomedical applications where nanoparticle agglomeration could so far only be prevented by using unwanted surfactants.
An attempt was made to control the surface charge of colloidal silica nanoparticles with 20 nm and 100 nm diameters. Untreated silica nanoparticles were determined to be highly negatively charged and have stable hydrodynamic sizes in a wide pH range. To change the surface to a positively charged form, various coating agents, such as amine containing molecules, multivalent metal cation, or amino acids, were used to treat the colloidal silica nanoparticles. Molecules with chelating amine sites were determined to have high affinity with the silica surface to make agglomerations or gel-like networks. Amino acid coatings resulted in relatively stable silica colloids with a modified surface charge. Three amino acid moiety coatings (L-serine, L-histidine, and L-arginine) exhibited surface charge modifying efficacy of L-histidine > L-arginine > L-serine and hydrodynamic size preservation efficacy of L-serine > L-arginine > L-histidine. The time dependent change in L-arginine coated colloidal silica was investigated by measuring the pattern of the backscattered light in a Turbiscan™. The results indicated that both the 20 nm and 100 nm L-arginine coated silica samples were fairly stable in terms of colloidal homogeneity, showing only slight coalescence and sedimentation.
Because traditional synthesis methods pose great hazards for the environment, there is a need to develop biomimetic processes for the treatment of industrial effluents and contaminated water in which the use of plant parts is an important alternative. Zerovalent iron nanoparticles having an average size of 59.08 ± 7.81 nm were prepared by mixing ferric nitrate with liquor of commercially available tea. Stirring of contaminated water with zerovalent iron nanoparticles supported on montmorillonite K10 for 30 min resulted in up to 99% removal of arsenic as As(III) from its solution at both high and low pH. It was also observed that, under similar conditions, montmorillonite K10 alone provided only <10% removal of As(III) from water. Adsorption at low pH with precipitation at higher pH has been proposed for As(III) removal. IR, XRD, SEM, and surface area studies were performed to confirm the reported results.
The influence of pH between 7.5 and 10.5, for 5% and 6.42% aqueous Wyoming bentonite dispersions and of NaCl for 2%, 5% and 6.42% of Wyoming-bentonite in water for a range of salt concentrations up to 1.0 M has been investigated. The dispersions were prepared according to American Petroleum Institute procedures and rheological data were obtained with a Couette viscometer. Data were represented very well by the Herschel–Bulkley model for all experimental conditions.The effect of pH and electrolyte concentration is significant, affecting the type of association of the montmorillonite particles thus influencing the rheology, the three Herschel–Bulkley parameters and the apparent viscosity. There is a maximum of the yield stress, flow consistency index and apparent viscosity at the natural pH of the dispersions, while there is monotonous decrease of these parameters with increasing salt concentration. Various scenarios of particle associations are discussed and comparison with similar data from literature is also performed.
Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed.
Nanotechnology has gained a great deal of public interest because of the needs and applications of nanomaterials in many areas of human endeavors including industry, agriculture, business, medicine, and public health. Environmental exposure to nanomaterials is inevitable as nanomaterials become part of our daily life, and, as a result, nanotoxicity research is gaining attention. This review presents a summary of recent research efforts on fate, behavior, and toxicity of different classes of nanomaterials in the environment. A critical evaluation of challenges and future needs for the safe environmental nanotechnology are discussed.
Production from unconventional hydrocarbon resources, such as shale gas, shale oil, deepwater and arctic reservoirs requires advanced drilling and extraction technologies. Furthermore, minimizing the environmental footprints associated with oil recovery processes are critical. Nanotechnology has been shown promising solutions to overcome such issues in oil and gas industry. Many studies have been conducted to analyse the enhancement of drilling fluids through the use of nanotechnology. In these studies modification of rheological, filtration, and heat transfer properties and friction reduction associated with drilling fluids have been investigated. They also showed that nanoparticles can improve fluid thermal stability, provide better lubricity, hole cleaning and wellbore stability, and mitigate hydrates formation within the fluid circulation system. This manuscript aims to analyse the outcomes of these studies and improvements that were observed for the application of nanoparticles in drilling fluids. This review provides the investigators with a detailed overview and comparison of the recent advancements in the field of drilling fluids and nanotechnology.
This study aimed mainly to evaluate the influence of xanthan gum (XG) and carboxymethylcellulose (CMC) in the filtration process of water-based drilling fluids, considering the conformational changes suffered by the polyelectrolyte with the addition of salt (NaCl) in different concentrations (0.17, 0.34 and 0.51 M). It was also evaluated the behavior of the fluid by the addition of calcite (calcium carbonate, CaCO3). Sixteen drilling fluids were prepared with the same xanthan gum concentration (major application as thickener to transport the cuttings), but different salinities and having or not CMC and calcite at constant concentrations. This strategy was adopted to evaluate the real contribution of each additive in the control of filtration performance, frequently unclear in the papers. In general, the fluids prepared in all brines showed lower viscosities and higher filtrate loss compared to fluids of sweet water. This effect was more strong in fluids containing only XG. The addition of CMC enhanced the viscosity and reduced the filtrate loss. However, the best results were obtained when calcite was added. The results indicated that XG contribution as thickener is not enough to control efficiently the fluid filtration even in the presence of calcite. However, the addition of CMC and calcite to XG salt solution increased the viscosity and decreased significantly the filtrate loss. This result was attributed to synergistic interactions between XG, CMC and calcite.
Composition and Properties of Drilling and Completion Fluids, Seventh Edition, delivers the most up-to-date information on drilling fluid choices and techniques. Long considered the mud bible for the oil and gas professional for over 60 years, this revised reference presents the service provider and operator with full disclosure on the many drilling and completion fluid chemistries available so that all parties are aware of not only their options prior to well selection, but also the latest environmental regulations and limitations of usage. New additions to the edition include a completely revised chapter on the introduction to drilling fluids, updated information on the evaluation of drilling fluids, common drilling challenges, and an entirely new chapter devoted to fracturing to meet today's market needs for the new and veteran oil and gas professional. The book remains the critical resource for making the best chemical and process flow selections when drilling and completing today's more complex oil and gas wells. Updated and reorganized with completely new material on all fracturing fluids, evaluation techniques, and drilling waste management Defined as the mud bible since its first publication in 1948 Upgraded with the newest references and regulations necessary to ensure safe and sustainable working conditions for the well and rig personnel.
As high-pressure/high-temperature (HP/HT) drilling is inherently expensive, drilling fluids and technologies should be carefully selected to successfully handle the associated challenges. Over the past few years, nanoparticles (NPs), among other additives, have been investigated to address these challenges. The objective of this study is to investigate the potential of using ferric oxide NPs on the filter cake properties in downhle drilling environments.
Having an efficient filter cake is an important property of the drilling fluid and can affect the success of drilling operations. This research focuses oncharacterizatingthe filter cakes produced by Ca-bentonite-based drilling fluid contains ferric oxide NPs at downhle conditions. A combination of computed-tomography (CT) scan and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) was used in filter cake characterization. The effect of NP concentration, fluid preparation method, and filtration condition were studied. A HP/HT filter press was used to perform the filtration process at conditions up to 350°F and 500 psi. Indiana limestone core disks were used to simulate the filter media.
The experimental results showed that the ferric oxide NPs improve the filter cake and filtration properties of Ca-bentonite-based drilling fluid in the presence of polymer and other additives. Low NP concentration is preferred for obtaining a good cake quality with the best characteristics obtained at 0.3–0.5 wt% NPs. Furthermore, this drilling fluid can withstand conditions up to 500 psi and 350°F. Cake properties of 0.151 in. thickness, 6.9 ml filtrate volume, and 0.428 µd permeability was obtained at such conditions. The addition of NPs to the drilling fluid improved the filter cake properties under both static and dynamic filtration. SEM-EDS analysis confirmed the efficiency of using NPs to form a smoother/less porous filter cake morphology. Moreover, sonication for one hour and hydration for 16 hours are recommendedfor better preparation of these fluids.
This research provides an experimental evaluation of using ferric oxide NPs with Ca-bentonite-based drilling fluid to produce high-quality filter cake at downhole conditions. The characteristics of the generated filter cake confirmed the efficiency of such fluids.
Rheological and filtration properties of water based muds play vital roles to have a good drilling efficiency in high pressure high temperature (HPHT) environments. However, there are many occasions where controlling the variation of mud properties due to disintegration of additives is barely possible, resulting in stuck pipe, kick incident or even loss of wells. Although there have been many studies in the past indicating the application of nanosilica in improving the flirtation control of water base muds, there are almost no studies on the significant reduction of the yield point which may cause a huge decrease in cutting carrying capacity of muds and rate of penetrations. The aim of this study is to propose an approach to improve the filtration control of water based muds using nanosilica while maintaining the rheology by using a cationic surfactant.
The results obtained from zeta potential measurements indicated that bentonite and nanosilica particles are both negatively charged at different ranges of pH, which would result in reduction of the yield point of the mud samples containing nanosilica. This issue was resolved by employing a cationic surfactant and following certain procedures. Filtration tests conducted under LPLT and HPHT conditions indicated that adding modified nanosilica into the mud samples creates a thin and low permeability filter cake without having any negative impacts on the rheology.
Temperature affects significantly the rheological behavior of neat water Wyoming Na-bentonite dispersions. The results of a very systematic study are presented regarding rheological measurements of 7% mass concentration at different temperatures, ranging between 25 and 80 °C at atmospheric pressure. Higher temperature increased the shear stresses at low shear rates while the effect was much smaller at higher shear rates. The Herschel-Bulkley rheological model fitted extremely well all data. The yield stress increased linearly with temperature by almost three-fold, the flow consistency index decreased exponentially with temperature by almost five-fold and the flow behavior index increased by about 20%, tending towards the Newtonian value. At low shear rates (< 100 rpm corresponding to < 170 1/s Newtonian shear rates), which represent very well the shear rates experienced by drilling fluids in the critical annulus region, all rheograms appeared fairly linear and the Bingham plastic model fitted well all data. The Bingham yield stress, from the low shear rate data, increased linearly with temperature, while the plastic viscosity decreased with temperature, in a manner very similar to the decrease of water viscosity with temperature. The plastic viscosity and Bingham yield stress data, from the low shear rate range, can be fitted well by an Arrhenius-type equation, with the activation energy for the plastic viscosity very similar to the activation energy for water viscosity, while for the Bingham yield stress, the activation energy is equal but opposite in sign to that of the plastic viscosity. A hypothesis is stated for the the observed linear increase of the yield stress with temperature, in the temperature range studied. One should be concerned when non-standard preparation and measurement procedures are followed which makes extremely difficult to understand any differences observed when reporting rheological data of water bentonite dispersions. A standard methodology is proposed, complementary to API, which can give very consistent results.
Drilling fluid must fulfill various functions with a great impact on the drilling performance. Drilling fluid invasion can cause formation damage. Good quality mudcakes can prevent such damage. This research focuses on the lab techniques and performance results of testing innovative water-based drilling fluids containing nanoparticles (NPs) for minimizing formation damage at high-pressure/high-temperature (HP/HT) conditions.
A couette type viscometer was used to examine the rheological properties of the drilling fluids tested in this research. Zeta potential measurements were conducted at different temperatures and concentrations to assess their stability and to investigate the role of charge potential. Indiana limestone outcrops were examined as the filter media for both static and dynamic filtration (up to 350°F and 500 psi) using a HP/HT dynamic filter press. The mudcakes were investigated using a computed-tomography (CT) scan, and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) was used to measure the concentrations of key ions in the filtrate fluids.
A significant reduction in the filtrate fluid volume was achieved when using ferric oxide NPs (-43% for 0.5 wt%) compared to that of the base fluid. However, adding silica NPs led to an increase in the filtrate volume and mudcake thickness. Increasing the NP concentration resulted in an increase in the fluid loss and mudcake thickness. The mudcakes consisted of two layers, as indicated by the CT scan analysis. 0.5 wt% was found to be the optimal NP concentration, which provides less agglomeration and a reduction in the mudcake permeability by -76.4%. At this concentration, the ICP-OES analysis showed a higher cation dissociation, which promoted the formation of a different clay platelet microstructure. At a higher NP concentration, a new layer of NPs was formed in the mudcake, which adversely affects the mudcake characteristics, as demonstrated by CT scan analysis and SEM-EDS elemental mapping. The rheological measurements indicated a good rheology at different temperatures and NP concentrations. Moreover, the NPs helped to stabilize the viscosity and yield stress at high temperatures (up to 200°F). Aging at 350°F for 16 hours showed that NP-based drilling fluids remain stable with minor changes in rheological properties. The obtained rheological data for various NPs is fitted to the classical drilling fluid rheological models to determine the best fit-model, which can then be applied to an efficient design.
This research provides a comprehensive evaluation of improved water-based drilling fluids, using ferric oxide and silica NPs for HP/HT applications. The examined NPs have the potential to enhance drilling fluid properties, which provides more efficient drilling operations and less formation damage.
Bentonite-supported “green” nanoscale zero-valent iron (B-nZVI) were prepared using green tea extracts characterized and employed for Cr(VI) adsorption. FE-SEM-EDS, TEM confirmed that nZVI (40–80 nm) has been successfully loaded and efficiently dispersed on bentonite. According FTIR and EDS analysis the synthesized B-nZVI were composed of polyphenols and other C-containing molecules from green tea extracts acting as both reducing and capping agents. Batch experiments were conducted to measure the effects on adsorption of Cr(VI) of different parameters such as initial concentrations, ionic strength, adsorbent dosage, pH of the medium and contact times. The results showed that synthesized B-nZVI has much higher adsorption capacity for Cr(VI) compared to bentonite. The adsorption was highly dependent on pH providing maximum adsorption at pH range of 2–6. The adsorption isotherm and kinetic data for B-nZVI was fitted well with the Langmuir and pseudo-second order model, respectively, which implied that the adsorption process was chemisorptions. The results of soil experiment showed that the addition of adsorbents including bentonite and B-nZVI decreased the release of Cr as compared with Cr-control treatment. However, application of B-nZVI (2 and 4%) significantly reduced the exchange fraction (EX) and subsequently increased the Fe[single bond]Mn oxide-bound (ox), and residual (RS) fractions. These results indicated the adsorption property of B-nZVI gives the compound with great potential for applications in environmental remediation.
Nano and micron materials are investigated in water-based drilling fluid (WBDF) to improve its rheological behaviour. Due to the environmental and certain operational concerns, the use of oil-based drilling fluid (OBDF) and synthetic based drilling fluid (SBDF) is restricted that caused the industry seeking for new ways to enhance rheological properties of WBDF. This study was based on investigating the applicability of multi-walled carbon nanotube (MWCNT), nanosilica and glass beads (GBs) as primary additives for enhancing the filtrate volume, lubricity and other rheological properties of WBDF. This study focused on the effect of different concentrations such as 0.001 ppb, 0.002 ppb, 0.01 ppb, 0.02 ppb, 0.1 ppb, and 0.2 ppb of each MWCNT and nanosilica over the rheological performance of WBDF. Effect of GBs of different sizes such as (90–150 μm) and (250–425 μm) was investigated at different concentrations of 2 ppb, 4 ppb, 6 ppb, 8 ppb, 10 ppb, and 12 ppb over rheological performance of WBDF. Results revealed that coefficient of friction (CoF) for drilling fluid without nanoparticles and GBs was 0.238. 0.01 ppb of MWCNT and nanosilica provided 44% and 38% CoF reduction. 4 ppb of GBs (90–150 μm) provided 28% CoF reduction. MWCNT showed 4.5 ml of filtrate volume and 2/32 inch of mud cake thickness. Thus, MWCNT can be a better choice as a drilling fluids additive for WBDF.
This research aims to develop low cost, sustainable, environmentally friendly, and high performance water-based drilling fluids (WDFs) using bentonite (BT), polyanionic cellulose (PAC), and cellulose nanocrystals (CNCs). The effect of concentration of BT, PAC, and CNCs on the rheological and filtration properties of PAC/CNC/BT-WDFs was investigated. Eight empirical rheological models were applied to fit quantitatively the fluid properties. Results showed that the presence of PAC, CNCs, and BT improved the rheological and filtration properties of the WDFs. Among the eight empirical rheological models, the Sisko model performed the best in simulating the rheological behavior of the fluids. At the same concentration level of PAC and CNCs, CNCs had more impact on the rheological properties, whereas PAC had more influence on the filtration property. The incorporation of PAC resulted in very low permeable filter cakes, leading to the excellent filtration property. The combined use of PAC and CNCs yielded better rheological and filtration properties.
Fe3O4 and Fe3O4/bentonite were prepared by chemical co-precipitation method. They were characterized by X-ray powder diffraction (XRD), Fourier infrared spectroscopy (FTIR), and transmission electron microscope (TEM). Adsorption of cobalt(II) on the bentonite, Fe3O4, and Fe3O4/bentonite nanocomposite was studied. The results indicated that the metal oxides mainly occurred in the form of spinel structure of Fe3O4 and the presence of Fe3O4 significantly affect the surface area and pore structure of the bentonite. The specific surface area (Brunauer–Emmett–Teller (BET) method) of bentonite, Fe3O4, and Fe3O4/bentonite were determined to be 34.44, 98.44, and 140.5 m2 g−1, respectively. TEM image of Fe3O4/bentonite shows the particle diameter at 10 nm. The maximum adsorption capacity of cobalt(II) by Fe3O4/bentonite nanocomposite was determined to be 18.76 mg g−1. The adsorption strongly depends on pH, where the removal efficiency increases as the pH turns to alkaline range (pH 9). The results suggest that higher adsorption capacity of composite than bentonite is attributed to the presence of Fe3O4. The adsorption process follows pseudo-second-order kinetics. The equilibrium data was analyzed by Langmuir model showing high correlation coefficient. The thermodynamic study of adsorption process showed that the adsorption of Co(II) onto Fe3O4 /bentonite was carried out spontaneously.
Rheological and filtration characteristics of drilling fluids are considered as two critical aspects to ensure the success of a drilling operation. This research demonstrates the effectiveness of cellulose nanoparticles (CNPs), including microfibrillated cellulose (MFC) and cellulose nanocrystals (CNCs) in enhancing the rheological and filtration performances of bentonite (BT) water-based drilling fluids (WDFs). CNCs were isolated from MFC through sulfuric acid hydrolysis. In comparison with MFC, the resultant CNCs had much smaller dimensions, more negative surface charge, higher stability in aqueous solutions, lower viscosity, and less evident shear thinning behavior. These differences resulted in the distinctive microstructures between MFC/BT and CNC/BT-WDFs. A typical "core-shell" structure was created in CNC/BT-WDFs due to the strong surface interactions among BT layers, CNCs and immobilized water molecules. However, a similar structure was not formed in MFC/BT-WDFs. As a result, CNC/BT-WDFs had superior rheological properties, higher temperature stability, less fluid loss volume, and thinner filter cakes than BT and MFC/BT-WDFs. Moreover, the presence of polyanionic cellulose (PAC) further improved the rheological and filtration performances of CNC/BT-WDFs, suggesting a synergistic effect between PAC and CNCs.
The fluid filtration and rheological properties of low solid content (LSC) bentonite fluids containing iron-oxide (Fe2O3) nanoparticle (NP) additives and two different NP intercalated clay hybrids, iron-oxide clay hybrid (ICH) and aluminosilicate clay hybrid (ASCH), under both low-temperature low-pressure (LTLP: 25 degrees-C, 6.9 bar) and high-temperature high-pressure (HTHP: 200 degrees-C, 70 bar) conditions are investigated. The viscosity of each fluid was measured under LTLP and HTHP conditions using a pressurized and heated rotational viscometer. The LTLP and HTHP fluid filtrate volumes were measured in accordance to American Petroleum Institute standards. The addition of ICH and ASCH into bentonite solutions reduced both LTLP and HTHP fluid loss as much as 37% and 47% as compared to the control, under the respective conditions. The pure addition of 0.5 wt.% 3 and 30 nm Fe2O3 NP increased the LTLP fluid filtration as much as 14% as compared to the control. However, this addition of Fe2O3 NP decreased the HTHP fluid filtrate volumes as much as 28% as compared to the control. It was found the addition of clay hybrids reduced LTLP and HTHP fluid loss due to a restructured mode of clay platelet interaction attributed to a modification in surface charge as demonstrated by zeta potential measurements and scanning electron microscope images.
Only scant and conflicting information is available in the literature on the effect of temperature on flocculation. In the present work an attempt was made to determine the effect of temperature on zeta potential, the rate of flocculation, and the optimum pH and dosage of flocculant. Cell electrophoresis and light absorption techniques were used in flocculation experiments. Bentonite and kaolinite clays dispersed in distilled water were chosen as dispersion systems. Alum and three polyelectrolytes (cationic, anionic and non-ionic) were used as flocculants. The temperature range investigated was 1°–20°C. The results indicate that: 1.1. Temperature has no significant effect on the zeta potential of a clay particle dispersed in water. This is in agreement with the theoretical prediction of the Poisson-Boltzman equation.2.2. Charge neutralization is an important factor in the flocculation of charged clay dispersion. However, the degree of charge neutralization necessary for effective flocculation depends strongly on the nature of the clay used.3.3. There is some correlation between zeta potential and flocculation. In the case of alum, for example, zeta potential may be used as a criterion of flocculation.4.4. The optimum pH for a given degree of flocculation varies with temperature when alum is used as flocculant. However, when flocculation is carried out at optimum pH conditions temperature has no effect. This supports the kinetic equations of Smoluchowski.5.5. When cationic polyelectrolytes are used for flocculation of aqueous dispersion, the rate of flocculation, the optimum pH, and the flocculant dosage required to achieve a given degree of flocculation are independent of temperature. This is interesting from a practical point of view, for example when the substitution of alum with a cationic polyelectrolyte flocculant is considered in a water treatment facility.
Yield stress of aqueous bentonite dispersions was determined at two concentrations, with two bentonites, over a range of pH values, with the vane technique and by extrapolation of the full rheograms, derived with concentric cylinder viscometer, fitted to Herschel–Bulkley and to Casson models. All samples exhibited a yield stress and gave very similar yield stress values determined by the three techniques and hence, any of the techniques can be used for measurement of the yield stress. Data extrapolation using either the Herschel–Bulkley or the Casson model would be favoured, though, because it gives, in addition to the yield stress, the rheological model parameters. The close matching observed for all three techniques is attributed to preparation and intensive preshearing procedures, similar to ones experienced by fluids in flow situations. pH of dispersions affected their yield stress but the effect was different for the two bentonites and the two concentrations tested. Measurement time at each rotational speed should be kept at a minimum of 60s. Bentonite dispersions build continuously structure over time and the yield stress evolution with time could be well described by power law. A model to predict yield stress, previously suggested for suspensions at the isoelectric point, could be a good starting point for yield stress prediction of bentonite dispersions.
A new method is discussed to improve the HPHT stability of conventional rheology modifiers and fluid loss polymers used in water-based drilling fluids. The method exploits the interactions of polysaccharides (e.g. xanthan gum, scleroglucan), cellulosics (e.g. CMC, PAC) and starches with polyglycols. Polymer and polyglycols were found to associate by inter-molecular hydrogen bonding and hydrophobic interactions. This association / complexation was found to stabilize the polymers at higher temperatures. Our laboratory findings are validated by field observations in the Kakap field in Indonesia that show improved HPHT stability when adding polyglycols to water-based drilling fluid formulations.
In the present work freeze drying and wet-pressing technologies are applied and evaluated in the manufacturing process of functional ceramics such as MnZn power ferrites. In particular, the implementations of freeze drying instead of spray drying and the implementation of wet pressing instead of dry uniaxial pressing are investigated. It appeared that at high frequencies there is almost 25% power loss reduction by the implementation of freeze drying instead of spray drying. At low frequencies there is almost 23% power loss reduction by the implementation of wet pressing instead of dry pressing. By introducing wet pressing technology, MnZn ferrite materials exhibiting power losses of 210 mW cm -3 (100 kHz, 200 mT and 100 °C) could be synthesized. This is one of the lowest power loss values reported in the scientific or patented literature.
The yield stress of a dialyzed system containing 3 % of the low particle size fraction of sodium Wyoming bentonite decreases on the addition of a few mequiv./l. of a neutral salt like NaCl. On further addition of salt the yield stress increases and, contrary to the pure gel, the system displays a slow thixotropic stiffening. The structure formation in the pure gel is attributed to edge to flat surface association of the plate-like micelles due to the opposed charges of the double layers at these surfaces. The structure of the thixotropic gel is seen as the result of the predominance of the van der Waals attraction forces between both lateral and flat surfaces of the different particles.
Fluid loss during drilling operations has a very significant effect on both reservoir formation damage and monetary terms. There are many additives to control this unwanted phenomenon. Nevertheless, most of these substances are artificial chemicals. Thus, they are not only expensive, but also hazardous to the environment. In this article, a more natural method was applied to overcome the higher filtration problems by employing carboxyl methyl cellulose (CMC) and polymers (XT), DSHV, and MAC PR. Drilling fluids were prepared due to American Petroleum Institute (API) standards. The fluid weights were adjusted as 9 ppg. API filtration tests were applied to fluid samples including the chemicals. Tests were also conducted with non-treated bentonites + barite fluids without chemicals for comparative purposes. All of the rheological parameters including plastic and apparent viscosity and yield points were determined. Comparative graphs of shear stress vs. shear rates were plotted. The optimum CMC and polymer amounts were selected by graphical analysis of the results of rheological tests made by using shear meter and filtration tests. An optimization of the fluid loss control due to addition of the chemicals was made. The behavior of water-based fluids with CMC and polymers was examined. The accurate and sensitive industrial application of this study would reduce drilling fluid loss expenditures effectively.
Zusammenfassung
1.
Von den Gleichungen, die die Strmung durch eine Kapillarrhre ausdrcken, ist
die fr Lsungen von Rohgummi in Benzol bis zu einer Konzentration von 1,2 Proz. am besten anwendbare.
2.
Die Methode der Konsistenzbestimmung durch Benutzung dieser Gleichung hat den Vorteil, da sie verwendbare Werte fr alle
praktischen Strmungsgeschwindigkeiten liefert und da sie die Notwendigkeit, sehr hohe Drucke anzuwenden, vermeidet.
3.
Die Vermeidung der hohen Drucke gestattet die Verwendung einer einfacheren Versuchsanordnung und vermindert den Fehler, der
durch die Unsicherheit in der Anwendung der kinetischen Energiekorrektion verursacht wird. Es wrde dies also mglich machen,
das Ostwald-Viskosimeter zu benutzen bei migen ueren Drucken, ohne Gefahr zu laufen, am Ende einer Messung Luft durch
die Kapillare zu blasen.
4.
Bei der Benutzung des logarithmischen Strmung-Druckdiagramms knnen genauere Uebereinstimmungen fr Kapillaren verschiedener
Dimensionen erhalten werden als bei Bestimmung von Scherungsmodul, Steifigkeit oder Beweglichkeit.
5.
Die Materialkonstanten n und I werden aus der logarithmischen Kurve erhalten und nehmen beide mit der Konzentration zu. Verglichen
mit Scherungsmodul und Bewegliċhkeit haben diese beiden Konstanten den Vorteil, da sie beide die Strmung in demselben Sinne
beeinflussen, also grere Plastizitt eines Stoffes grere Werte fr n und I bedingen wrde.
6.
K verschwindet bei groen Kapillaren und geringen Konzentrationen oder ist zu klein, um ermittelt zu werden. Wenn K jedoch
bestimmbar ist, wchst sein Wert mit Abnahme des Kapillarendurchmessers. K selbst ist keine Materialkonstante, aber weitere
Untersuchungen sollen zeigen, da aus ihm eine dritte Konstante berechnet werden kann.
Organic polymers are commonly used to control the rheology and filtrate loss required for water-based drilling fluids. An ecologically-friendly water-based drilling fluid was developed by studying the rheological behavior of tamarind gum and polyanionic cellulose on bentonite water suspensions. The effect of drilling fluid filtrate on formation damage was also analyzed. The drilling fluid that was developed has better rheological properties and fluid loss control which are required for optimum performance of oil well drilling. In addition, the drilling fluid filtrate exhibits minimum formation damage on sandstone cores
The pH-dependent adsorption of humic acid (HA) on magnetite and its effect on the surface charging and the aggregation of oxide particles were investigated. HA was extracted from brown coal. Synthetic magnetite was prepared by alkaline hydrolysis of iron(II) and iron(III) salts. The pH-dependent particle charge and aggregation, and coagulation kinetics at pH ∼ 4 were measured by laser Doppler electrophoresis and dynamic light scattering. The charge of pure magnetite reverses from positive to negative at pH ∼ 8, which may consider as isoelectric point (IEP). Near this pH, large aggregates form, while stable sols exist further from it. In the presence of increasing HA loading, the IEP shifts to lower pH, then at higher loading, magnetite becomes negatively charged even at low pHs, which indicate the neutralization and gradual recharging positive charges on surface. In acidic region, the trace HA amounts are adsorbed on magnetite surface as oppositely charged patches, systems become highly
unstable due to heterocoagulation. Above the adsorption saturation, however, the nanoparticles are stabilized in a way of combined steric and electrostatic effects. The HA coated magnetite particles form stable colloidal dispersion, particle aggregation does not occur in a wide range of
pH and salt tolerance is enhanced.
The crystallization of ice during preparation of soil clays for freeze-drying can cause aggregation of clay particles. This often results in sample loss by the ejection of material in the water vapour stream during sublimation. These undesirable effects are overcome with many soil clays by the addition of ethanol to a concentration of approximately 4% in the suspension before freezing. The structure of the clay body obtained by freeze-drying appears to depend mainly on the particle-size distribution of the clay; a more coherent structure being obtained from finer clays.
Given the ubiquity of natural clay minerals, the most likely interaction of nanoparticles released into an aquatic environment will be with suspended clay minerals. Thus, the transport of engineered nanoparticles in the subsurface and the water column will most likely be altered by their interaction with these minerals. We studied the interactions of two of the most produced nanoparticles, Ag and TiO(2), and montmorillonite to determine how heteroaggregation can alter the stability of nanoparticle/clay mineral mixtures. Since at low pH montmorillonite has a negatively charged basal plane and positively charged edges, its interaction with these nanoparticles at different pH lead to unusual behaviors. There are six different interactions for each clay-nanoparticle pair. At pH values below the IEP of montmorillonite edge site, montmorillonite reduced the stability of both negatively charged Ag and positively charged TiO(2) nanoparticles. Surprisingly this enhanced coagulation only occurs within an intermediate ionic strength range. The spillover of the montmorillonite basal plane electric double layer to the montmorillonite edge may screen the electrostatic attraction between Ag and the montmorillonite edge at low ionic strength, whereas a repulsion between TiO(2) and montmorillonite face sites may restabilize the mixture.
The use of bentonites as adsorbents results from the reactivity of montmorillonite which is the main mineral in this clay-like
material. Montmorillonite, a 2:1 clay mineral, impresses by a diversity of reactions in the interlayer space and at the external
surfaces, which are the cause of strong adsorption of heavy metal ions and organic compounds. Bentonite adsorbents are used
as crude bentonite, in soda-activated form, after degradation to bleaching earths, after modification by organic cations,
or in form of polyhydroxometal or polyoxometal derivatives (“pillared clays”). The ease with which the bentonites are modified
allows an optimization of the properties so that the requirements of numerous practical applications are fulfilled.
Flow of kaolin and bentonite dispersions is decisively determined by edge(+)/face(−) contacts (card-houses) in an acidic medium and face(−)/face(−) contacts (band-like structures) in an alkaline medium. Formation of the different networks depends on pH and ratio. Calcium ions promote face(−)/face(−) contacts and stabilize band-like structures.In alkaline dispersions of homoionic sodium smectites and at low salt concentration, sodium ions cause disintegration of the particles into thinner lamellae and stacks of silicate layers which, at low solid content (about <5%), move independently under applied stress (Newtonian flow). These dispersions are sensitive to the ratio. Some amounts of calcium ions link the lamellae and stacks of layers to form band-like networks, and the consistency of the dispersion increases considerably.Admixed crystalline or non-crystalline materials affect the flow of clay dispersions when they interact with the clay minerals. An example is the influence of iron oxides. Organic compounds can stabilize or destabilize networks, which is demonstrated for surface active agents and kaolinite.
The transition between stable colloidal dispersions and coagulated or flocculated systems is a decisive process in practical applications of million of tons of bentonites (containing the clay mineral montmorillonite). Dispersion into the colloidal state requires the transformation of the original bentonite into the sodium form, for instance by soda activation. Therefore, we review here the coagulation of sodium montmorillonite dispersions by inorganic and organic cations and the influence of compounds of practical interest such as phosphates, cationic and anionic surfactants, alcohols, betaine-like molecules and polymers like polyphosphates, tannates, polyethylene oxides with cationic and anionic end groups, and carboxy methylcellulose. Typical properties of the sodium montmorillonite dispersions are the very low critical coagulation concentrations, the specific adsorption of counterions on the clay mineral surface, and the dependence of the cK values on the montmorillonite content in the dispersion. In most cases coagulation occurs between the negative edges and the negative face. The phosphates Na2HPO4, NaH2PO4 and Na4P2O7 increase the edge charge density and change the type of coagulation from edge (−)/face (−) to face (−)/face (−) with distinctly higher cK values. Polyanions like polyphosphate and tannate stabilize in the same way. Carboxy methylcellulose causes steric stabilization. Montmorillonite particles with adsorbed betaine-like molecules provide an example of lyosphere stabilization.
The effectiveness of Greek lignites to control the filtration characteristics of water–bentonite suspensions and to minimize formation damage at high temperatures was studied. Twenty-six lignite samples from various peat/lignite deposits in Greece were used together with a commercial lignite product. The contents of humic and fulvic acids, humins, oxygen, ash and the cation exchange capacity of lignite samples were examined with respect to fluid loss of these suspensions. The results show that most samples provided very good filtration control of the water–bentonite suspensions after exposure to 177 °C with some being superior to the commercial product. Better performance was observed after addition of 3% w/v lignite. Total humic and fulvic acids as percentage of dry lignite matter and the organic matter as lignite percentage showed a weak inverse correlation with the fluid loss volumes.
Drilling fluids containing bentonite and bentonite–lignite as additives exhibit non-Newtonian rheological behavior which can be described well by the three parameter Herschel–Bulkley rheological model. It is shown that determination of these parameters using standard techniques can sometimes provide non-optimal and even unrealistic solutions which could be detrimental to the estimation of hydraulic parameters during drilling. An optimal procedure is proposed whereby the best value of the yield stress is estimated using the Golden Section search methodology while the fluid consistency and fluid behavior indices are determined with linear regression on the transformed rheometric data. The technique yields in many cases results which are as accurate as these obtained by non-linear regression but also gives positive yield stress in cases where numerical schemes give negative yield stress values. It is shown that the impact of the values of the model parameters can be significant for pressure drop estimation but less significant for velocity profile estimation for flow of these fluids in drill pipes and concentric annuli. It is demonstrated that very small differences among the values of the model parameters determined by different techniques can lead to substantial differences in most operational hydraulic parameters in oil-well drilling, particularly pressure drop and apparent viscosity of the fluid at the drilling bit affecting penetration rates, signifying thus the importance of making the best simulation of the rheological behavior of drilling fluids.
Montmorillonite is the most often studied swelling clay mineral. The layers have permanent negative charges due to isomorphic substitutions, and pH-dependent charges develop on the surface hydroxyls at the edges. Wyoming montmorillonite samples with different extents of isomorphic substitutions (Swy-1 and Swy-2) were studied. The acid–base titration of Na-montmorillonite suspensions between pH 4 and 9 at 0.01, 0.1 and 1 M NaCl was used to characterize pH-dependent charge development on amphoteric edge sites and to determine the point of zero charge (PZC) of edges. The evaluation of reversible net proton surface excess vs. pH functions revealed that the OH groups at edges having PZC at pH ∼6.5 are less basic than the –OH and less acidic than the –OH groups. Positive charges can develop in a protonation reaction of –OH sites at edges only at pHs below ∼6.5, and deprotonation of –OH then that of the –OH sites takes place with increasing pH of solution resulting in negative charges at edges. Therefore, patch-wise charge heterogeneity of montmorillonite, i.e. oppositely charged surface parts of layers, exists only under acidic conditions. Coagulation kinetics measurements resulted in reliable stability ratio data for fine montmorillonite sols at different pHs, and provided undisputable characterization of hetero- and homocoagulation. Edge-to-face heterocoagulation occurs above NaCl concentration 25–26 mmol l−1 at pH ∼4, where the hidden electric double layer (edl) of positively charged edge region has emerged. Edge-to-face attraction between the poorly charged edges and negatively charged faces of platelets around the pH of PZC of edges (pHPZC, edge∼6.5) in relatively low concentration of the indifferent electrolytes (typically around 50 mmol l−1 NaCl) is probable. The homocoagulation of uniformly charged lamellae at pH 8–8.5, formation of face-to-face aggregates requires much higher salt concentration (typically around 100 mmol l−1 NaCl) to compress the dominant edl on the highly charged faces of particles. XRD patterns of montmorillonite films prepared from slightly acidic suspensions proved that formation of well-ordered layer packages is hindered by the attraction between edges and faces. Characteristic changes in gel formation and in rheological properties induced by decreasing pH in dense suspensions containing 0.01 M NaCl provided experimental evidence for the structure of particle network. A significant increase in thixotropy and yield values, and also the formation of viscoelastic gels only below pH ∼6.5 verify that attractive interaction exists between oppositely charged parts of lamellar particles.
Two different types of clay nanoparticle hybrid, iron oxide nanoparticle clay hybrid (ICH) and Al(2)O(3)-SiO(2) nanoparticle clay hybrid (ASCH), were synthesized and their effects on the rheological properties of aqueous bentonite fluids in steady state and dynamic state were explored. When ICH particles were added, bentonite particles in the fluid cross-link to form relatively well-oriented porous structure. This is attributed to the development of positively charged edge surfaces in ICH that leads to strengthening of the gel structure of the bentonite susensions. The role of ASCH particles on the interparticle association of the bentonite fluids is different from that of ICH and sensitive to pH. As pH of ASCH-added bentonite suspensions increased, the viscosity, yield stress, storage modulus, and flow stress decreased. In contrast, at low pH, the clay suspensions containing ASCH additives were coagulated and their rheological properties become close to those of ICH added bentonite fluids. A correlation between the net surface charge of the hybrid additives and the rheological properties of the fluids indicates that the embedded nanoparticles within the interlayer space control the variable charge of the edge surfaces of the platelets and determine the particles association behavior of the clay fluids.
The effect of particle concentration, size distribution (polydispersity) and magnetic attractive forces (Fe0 content) on agglomeration and transport of poly(styrene sulfonate) (PSS) modified NZVI was studied in water-saturated sand (dp = 300 μm) columns. Particle concentrations ranged from 0.03 to 6 g/L in 5 mM NaCl/5 mM NaHCO3 at a pore water velocity of 3.2 × 10-4 m/s. Three NZVI dispersions with different intrinsic particle size distributions obtained from sequential sedimentation are compared. The influence of magnetic attraction (Fe0 content) on NZVI agglomeration and deposition in porous media is assessed by comparing the deposition behavior of PSS-modified NZVI (magnetic) having different Fe0 contents with PSS-modified hematite (nonmagnetic) with the same surface modifier. At low particle concentration (30 mg/L) all particles were mobile in sand columns regardless of size or magnetic attractive forces. At high concentration (1 to 6 g/L), deposition of the relatively monodisperse dispersion containing PSS-modified NZVI (hydrodynamic radius (RH) = 24 nm) with the lowest Fe0 content (4 wt %) is low (attachment efficiency (α) = 2.5 × 10-3), insensitive to particle concentration, and similar to PSS-modified hematite. At 1 to 6 g/L, the attachment efficiency of polydisperse dispersions containing both primary particles and sintered aggregates (RH from 15 to 260 nm) of PSS-modified NZVI with a range of Fe0 content (10-60%) is greater (α = 1.2×10-2 to 7.2×10-2) and is sensitive to particle size distribution. The greater attachment for larger, more polydisperse Fe0 nanoparticles with higher Fe0 content is a result of their agglomeration during transport in porous media because the magnetic attractive force between particles increases with the sixth power of particle/agglomerate radius. A filtration model that considers agglomeration in porous media and subsequent deposition explains the observed transport of polydisperse PSS-modified NZVI at high concentration.
Humic acid (HA) coated Fe3O4 nanoparticles (Fe3O4/HA) were developed for the removal of toxic Hg(II), Pb(II), Cd(II), and Cu(II) from water. Fe3O4/HA were prepared by a coprecipitation procedure with cheap and environmentally friendly iron salts and HA. TOC and XPS analysis showed the as-prepared Fe3O4/HA contains approximately 11% (w/w) of HA which are fractions abundant in O and N-based functional groups. TEM images and laser particle size analysis revealed the Fe3O4/HA (with approximately 10 nm Fe3O4 cores) aggregated in aqueous suspensions to form aggregates with an average hydrodynamic size of approximately 140 nm. With a saturation magnetization of 79.6 emu/g, the Fe3O4/HA can be simply recovered from water with magnetic separations at low magnetic field gradients within a few minutes. Sorption of the heavy metals to Fe3O4/HA reached equilibrium in less than 15 min, and agreed well to the Langmuir adsorption model with maximum adsorption capacities from 46.3 to 97.7 mg/g. The Fe3O4/HA was stable in tap water, natural waters, and acidic/ basic solutions ranging from 0.1 M HCl to 2 M NaOH with low leaching of Fe (< or = 3.7%) and HA (< or = 5.3%). The Fe3O4/HA was able to remove over 99% of Hg(ll) and Pb(ll) and over 95% of Cu(II) and Cd(II) in natural and tap water at optimized pH. Leaching back of the Fe3O4/HA sorbed heavy metals in water was found to be negligible.
Three fulleropyrrolidine derivatives, characterized by the presence of positive charges, were introduced in the interlayer space of montmorillonite. The composites were characterized by powder X-ray diffraction and differential thermal and thermogravimetric (DTA-TGA) analysis, in conjunction with FTIR, UV-Vis, Raman, and (57)Fe-Mössbauer spectroscopies. Organophilic derivatives were intercalated into organically modified clays, while water-soluble fulleropyrrolidines were introduced into the clay galleries through ion exchange. The experiments, complemented by computer simulations, show that not all the clay-clay platelets are intercalated by the fullerene derivatives and that a sizable amount of charge transfer takes place between the host and the guests.