MOL

In this study our primary objectives were to describe and assess the potential source rocks in Hungary, focusing on parameters such as lateral extent, thickness, and organic richness. We investigated the burial and thermal evolution and timing of petroleum generation. Utilizing a substantial database of 1400 vitrinite reflectance and 6500 TOC/Rock-Eval data, we performed quantitative assessment of source rock potential per basin. A 93,000 km ² 3D basin model covering entire Hungary was created. In the Zala North Basin, the Upper Triassic Kössen Marl is the main source rock, charging the Nagylengyel oil fields. Lower-Middle Jurassic sediments in the Mecsek Unit were identified as fair quality gas-prone source rocks, potentially charging the nitrogen-rich gas fields in the Szolnok Flysch Zone. In the Paleogene Basin, the Lower Oligocene Tard Clay is the best source rock, with additional potential in the Upper Eocene Kosd Fm. and Buda Marl. The Badenian marine shales are the likely source rocks in the Zala South and the Dráva Basin and in the Somogy Trough. In the Kiskunság area, Karpatian lacustrine, Badenian marine and lower Pannonian Endrőd Marl source rocks charged the known fields, similarly to the Pusztaföldvár High, Békés Basin and in the Derecske Trough.

The Kohat Plateau in Pakistan features major Gas and Condensate producing fields with majority of the blocks owned and operated by two of the country's biggest E&P Operators. Operators are known to frequently encounter severe drilling challenges, and over time, have devised certain technology solutions that have helped curtail the major drilling challenges to a good extent, helping improve the time and cost expended in reaching the target depths. However, the problems arising after the Drilling cycle – foremost being Sustained Casing Pressure (SCP) – require expensive remedial treatments and loss of production; this paper presents a solution to this particular challenge of SCP including in-depth cause analysis, treatment design and implementation. In the analysis stage, the drilling data of wells experiencing SCP in one of the Casing annuli was reviewed to pinpoint possible areas of compromised well integrity. It was observed that sections having good Cement bonds and sufficient Top of Cement in the annulus also became compromised over time, indicating operations conducted after the drilling phase could be responsible for the annular fluid migration, and hence SCP. It must be noted that extensive drill-stem tests to assess the reservoir economics as well as production pressures generate significant dynamic stress on the well structure. Through the use of custom stress-analysis software for annular Cement, it was concluded that it is this stress that causes the primary isolation of the constructed well, the annular Cement, to fail allowing annular migration of formation fluids. A new class of stress-resistant, auto-repair Cements was seen to resist any mechanical failure under stress enabling Operators to drill wells with lasting structural integrity. Mechanical properties including Young's Modulus, Poisson Ratio and Annular Expansion co-efficient were analyzed to design a Cement system capable of withstanding the applied stress. The first in-country application was conducted as the Intermediate-section Cementing in a new well. The system exhibited good isolation with average 10mV amplitude (free pipe amplitude 51 mV) in Cased Hole bond logs and no annular pressure is observed till date in the section more than 02 years after the primary cementing operation. This design approach was subsequently extended to other fields, with successful applications that reduced, and in certain cases, eliminated the need for remedial work. By presenting a detailed field application of flexible and self-healing Cement, the paper puts forth a general, stepwise approach for the selection of a Cement design that promises lasting annular isolation and minimizes the risk of communication behind the casing.

Liquid blockage is a damage mechanism which occurs due to accumulation of immovable liquid phase near the wellbore area causing impairment of the relative permeability of the valuable hydrocarbons leading to significant reduction in production. The liquid block may be caused by the accumulation of condensates, water or immovable emulsions formed by interaction of incompatible fluids. These incompatible fluids may be introduced during the drilling operations or during the commingled production of fluids through single completion string. This damage may cause complete seizure of production in low pressure gas wells due to drastic reduction in the relative permeability of gas due to high mobility contrast. Similarly, the potential organic residue deposition in injection wells cause significant damage leading to abnormal injection pressures and rendering the operation expensive and uneconomical. A well-known solution for treating liquid blocks is the usage of alcohol-based treatments that work by reducing the viscous forces of the blocking fluid, reducing the interfacial tension, solubilizing the blocking water, causing vaporization, and subsequently removing the fluid blockage. Similarly, the aromatic fluids-based mixture with mutual solvent has been used for treatment of organic residue depositions and emulsion removal. However, limited applications of these solutions in the Indus Basin require further work on the subject to establish the minimum confidence on the successful solution recipe and development of the best practices for such wells. This paper demonstrates the practical application of utilization of these solutions for successful treatment of liquid blockage in 1st attempt, putting depleted gas well back at pre water block damage production level and significant improvement in injection pressures of another injector well saving multi folds cost of operation.

Drilling through overburden shale often presents operational challenges, particularly when drilling high-angle wells. Chemical imbalance between the shale and the drilling fluid can lead to time-dependent wellbore instability resulting in stuck pipe; cavings; and, under extreme circumstances, loss of the well. This study provides a unique workflow combining a suite of laboratory measurements to evaluate rock-fluid interaction between shale and drilling fluids. The testing suite includes X-ray diffraction (XRD) for mineralogical composition; tight rock analysis (TRA) for fluid saturations and petrophysical properties; mercury injection capillary pressure (MICP) for pore throat radius analysis, pore water composition and water activity (aw) that is measured at ambient and elevated pressure using a new test system (patent pending); pressure penetration and membrane efficiency tests to evaluate pressure transmission through shale when exposed to drilling fluids; and modified thick-walled cylinder (mTWC) tests for screening potential adverse effects of drilling fluid on rock strength. Test results show how water activity measurements using synthetic brines can vary significantly from measurements made directly from the rock and under in-situ stress conditions. Water activity measurements made under stress correlate well with clay content and pore throat radius. From mTWC tests, the imbalance of aw can generate shale swelling and strength reduction. The pressure transmission tests show how the drilling fluids can plug the pores and reduce the pressure transmission rate to the formation. These data are instrumental in providing mitigating measures to avoid instability problems during drilling through overburden shales. Introduction Drilling high-angle development wells in shale can pose many operational risks requiring optimization of casing points, knowledge of safe mud weight profiles, and selection of the drilling fluid to counter rock-fluid interaction. Often the mud weight needs to be high enough to prevent shear collapse but low enough to not induce weak-bedding-plane failure (mechanical tensile failure) in the overburden. To determine the drilling window and optimum drilling mud weight for the well design, basic well logs and drilling reports are not enough to solve the problem alone; core measurements and advanced sonic are key ingredients to the wellbore stability model and subsequent predictions. Laboratory tests address both mechanical behavior through plane of weakness testing and modeling coupled with anisotropic characterization (Xi et al., 2020; Shaver et al., 2020) and evaluation of chemical shale interaction with drilling fluids to determine the effects of drilling time-dependent instability. This paper provides a novel laboratory testing approach to characterize shale time-dependent behavior to optimize drilling fluids used for shale formations.

The southern part of the North Sea continental shelf is known for large intervals of hard, compact, cretaceous chalk formations that historically have proven to be challenging to drill through in one run. In recent years technology has been developed to drill specifically through these types of sedimentary successions as effectively as possible to be durable and competitive in similarly challenging drilling settings. Formations that previously would require multiple bit runs are now being drilled in one. The exploration well 2/9-6 S Eidsvoll, operated by MOL Norge AS, was drilled in this area of the North Sea continental shelf, with this specific type of chalk being drilled in the 12 ¼-in. section. Because the 12 ¼-in. section consisted of several different lithologies, it was vital to design the bottom hole assembly (BHA) to handle the diversity of rock formations to be drilled. Lithologies ranging from soft, swelling clay to hard compact chalk with an Unconfined Compressive Strength (UCS) as great as 20,000 psi were expected. In addition to managing the challenging drilling environment, determining the casing setting depth was of the highest priority because a pressure ramp was expected near the planned setting depth. This pressure ramp is located in the Base Cretaceous Unconformity (BCU), which is a well-known seismic reflector in the area. The top of this reflector had an uncertainty of ±75 m, which is not ideal following a decision to set the 9 ⅞-in. casing as near as possible to the reservoir. Seismic-while-drilling technology was applied to reduce this uncertainty and better tie-in the acoustic velocities to the pre-drilling seismic model. In addition, a geomechanics team was tasked with creating and updating the prognosed pore pressure estimation model. This information was important in making the mud-weight decision when drilling the 8 ½-in. section.

Characterizing the naturally fractured reservoir in a mature field is always a challenging task due to minimal subsurface data availability and the technology was not as advanced as nowadays. Therefore, this paper is proposed to provide an alternative solution to identify the presence of the fractures, classify them into the fractured quality related flowability, and distribute them vertically within the well interval and propose a lateral distribution method for reservoir modeling. This research was conducted based on a case study of basement fractured carbonate reservoir in Hungary. I used more than twenty development wells which mainly drilled during 1980-2000's. The fractures presence is simply identified by using gamma-ray and density logs. The relative movement of density log to the defined fractured baselines was directed to classify the fracture quality within three groups of macro-fracture, micro-fracture, and host-rock. These groups were validated by core data and the acoustic image log from the newest drilled wells. Furthermore, I implemented the self-organizing map (SOM) for distributing the fracture group to other wells which having limited subsurface data. Since the fracture classes were distributed along the well depth interval, then the well test (DST) results and production flow test data validated the flowability of them. As a result, the main flow contribution intervals of the fracture can be well-recognized. The macro-fracture consistently indicates the fracture class showing the main contribution of the liquid flowrate more than 10 m3/d along the perforated intervals. The rock properties of this class have porosity range around 1-2% with permeability dominantly more than 100 mD. In contrast, the host-rock class is defined as a protolith/non-fractured rock. The porosity and permeability are extremely low (tight rock). This class does not give any flow contribution due to the high content of the marl or clay, the absence of the fracture, or the fractures had been re-cemented by calcite or quartz minerals. Meanwhile, the micro-fracture denotes the group of rock with porosity range around 2-10% and permeability average between 1-10 mD. In general, the flowrate coming from this fracture class was lower than 10 m3/d of liquid during the flow-test. As a novelty, this proposed approach with the machine learning of SOM-clustering effectively assists us to recognize the fracture presence and its quality along the well-depth interval from the absence of the advanced technologies of image logs and production logging (PLT) measurement. Also, the defined fracture class here can take a role as a fracture facies or rock typing in terms of 3D reservoir modeling and distributed laterally based on fault-likelihood attribute and fault zone defined by distance-to-fault.

In this study, a novel efficient cathode electrode was fabricated to convert inorganic carbon to volatile fatty acids (VFAs) through microbial electrosynthesis (MES) in a single chamber reactor. The cathode catalyst was made up of mesoporous silica (mS) coated cerium oxide (CeO2) and carbonized cellulose (C) in which mS acts as core material and both CeO2 and C as a shell material. The CeO2/C was loaded on the porous surface of mS, which acted as catalytic centers to enhance the biochemical reactions. The C/CeO2@mS composite catalyst coated on carbon cloth (Cc) was characterized by XRD and FESEM, and showed a high crystallinity and porous core shell morphology. The cyclic voltammetry analysis indicated that the cathode with C/CeO2@mS exhibited higher catalytic activity (-0.59 mA/cm2 background current) than the other controls (0.26 mA/cm2 for MES-C and - 0.06 mA/cm2 for MES-mS). Three MES reactors with different cathodes were comparatively operated for the conversion of CO2 (8 g/L of HCO3), and MES- C/CeO2@mS exhibited a maximum acetate production (19.1 ± 0.95 mM) followed by MES-C (10.8 ± 0.51 mM) and MES-mS (9.5 ± 0.33 mM). The coulombic efficiency (CE %) in the MES- C/CeO2@mS was 76%, and it was 42% and 34% for MES-mS and MES-C, respectively. The maximum current generation (0.48 ± 0.21 mA/cm2) was obtained with MES- C/CeO2@mS at relatively higher cathode potential (-0.61 mV) than the other cathodes. The MES- C/CeO2@mS showed a lower Tafel slope of 220 mV/dec, which was 2.71 times lower than abiotic MES- C/CeO2@mS (598 mV/dec) suggesting enhanced electrokinetics with exoelectrogenic biofilm development on the cathode electrode. This study clearly demonstrates that the C/CeO2@mS catalyst can be successfully used for highly efficient bioelectrochemical conversion of CO2 to value added products via MES route.

The electrochemical CO2 reduction to oxalic acid in aprotic solvents could be a potential pathway to produce carbon-neutral oxalic acid. One of the challenges in the aprotic CO2 reduction are limited achievable current densities under standard conditions, despite the increased CO2 solubility compared to aqueous applications. The application of aprotic solvents can reduce CO2 rather selectively to oxalate, faradaic efficiencies (FE) to oxalate up to 80% were achieved in this study at a Pb catalyst in acetonitrile, the FE mainly being dictated by the local CO2 concentration at the electrode. This process was integrated into a flow cell employing a two-layered carbon-free lead (Pb) gas diffusion electrode (GDE) and a sacrificial zinc (Zn) anode. With the application of this GDE the applicable current densities could be improved up to a current density of j=80 mA·cm⁻² at a FE(oxalate)=53%, which is within the range of the highest j reported in literature. In addition, we provide an explanation for the deactivation mechanism of metal catalysts observed in aprotic CO2 reduction literature. The deactivation is not related to a mass transport limitation but to cathodic corrosion observed at highly negative potential when employing quaternary ammonium supporting electrolyte cations, promoting catalyst leaching.

Development of analytical methods for the characterization (particle size determination, chemical identification, and quantification) of the low μm-range microplastics (MPs; 1-10 μm) and nanoplastics (NPs; 1 nm to 1 μm) in air-coarse (PM10; <10 μm), fine (PM2.5; <2.5 μm) and ultrafine (PM1; <1 μm) particulate matter-is a quickly emerging scientific field as inhalation has been identified as one of the main routes of human exposure. The respiratory tract may serve as both target tissue and port of entry to the systemic circulation for the inhaled MPs and NPs with their small particle size. As an outcome, the interest of the scientific community, policy makers, and the general public in indoor airborne MPs and NPs increased tremendously. However, there is a lack of detailed knowledge on the indoor and outdoor sources of MPs and NPs, their levels, and their health impact. This is mainly related to a lack of standardized sampling and analytical methods for size determination, chemical identification, and quantification. In this review, recent developments in mass spectrometry-based analytical methods for size determination, chemical identification, and quantification of the MPs and NPs in indoor air and dust, are discussed.

A better understanding of the drivers of the economic, environmental, and social sustainability of emerging (biobased) technologies and products in early development phases, can help decision-makers to identify sustainability hurdles and opportunities. Furthermore, it guides additional research and development efforts and investment decisions, that will, ultimately, lead to more sustainable products and technologies entering a market. To this end, this study developed a novel techno-sustainability assessment (TSA) framework with a demonstration on a biobased chemical application. The integrated TSA compares the potential sustainability performance of different (technology) scenarios and helps to make better-informed decisions by evaluating and trading-off sustainability impacts in one holistic framework. The TSA combines methods for comprehensive indicator selection and integration of technological and country-specific data with environmental, economic, and social data. Multi-criteria decision analysis (MCDA) is used to address data uncertainty and to enable scenario comparison if indicators are expressed in different units. A hierarchical, stochastic outranking approach is followed that compares different weighting schemes and preference structures to check for the robustness of the results. The integrated TSA framework is demonstrated on an application for which the sustainability of a production and harvesting plant of microalgae-based food colorants is assessed. For a set of scenarios that vary with regard to the algae feedstock, production technology, and location, the sustainability performance is quantified and compared, and the underlying reasons for this performance are explored.

The extraction of Am(III), Cm(III) and Eu(III) by 2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-1,10-phenanthroline (CyMe4BTPhen) from nitric acid solution was studied using the ionic liquid Aliquat-336 nitrate ([A336][NO3]) as diluent. Results show a high selectivity of the solvent for Am(III) and Cm(III) over Eu(III), but rather slow extraction kinetics. The kinetics of CyMe4BTPhen were largely improved by the addition of 0.005 mol L⁻¹ N,N,N′,N′-tetra-n-octyl-diglycolamide (TODGA) as a phase transfer reagent and by the use of 1-octanol as co-diluent. The addition of the phase transfer catalyst and co-diluent did not compromise the selectivity towards the actinide/lanthanide separation and thus this four-component system can be successfully applied to separate Am(III) and Cm(III) from the lanthanides.

Boron neutron capture therapy (BNCT) is an extensively studied radiotherapeutic strategy for cancer treatment. BNCT is based on irradiation of malignant tumour cells with neutrons after uptake of a ¹⁰B containing molecule. Alpha particles, locally produced by neutron irradiation kill the cancer cells. Important for ongoing research regarding cellular uptake and cytotoxicity of a large variety of ¹⁰B containing molecules is the accurate determination of boron concentrations in cell cultures. In this work, the sample preparation for quantitative inductively coupled plasma mass spectrometry (ICP-MS) analysis on cell cultures was optimized. By making use of acid digestion combined with UV digestion, low detection limits (0.4 µg/L) and full recoveries of boron could be achieved while measurements were free of spectral and non-spectral interferences. Finally, cell-associated boron in the form of 4-borono-L-phenylalanine (L-BPA) in vascular endothelial cell cultures could be determined with ICP-MS as (1.26 ± 0.10) ·10⁹ boron atoms per cell. The developed method can prove its importance for further BNCT research and elemental analysis of cell cultures.

By benchmarking gas-diffusion electrocrystallization against alkaline precipitation for the synthesis of (hydr)oxide nanoparticles, oxidation-assisted precipitation of magnetite nanoparticles was demonstrated.

Conversion of 1-hexene or olefins obtained by fluid catalytic cracking (FCC) to propylene via isomerization-metathesis (ISOMET) were investigated using ethylene, as cross-coupling agent. Zeolite H-beta (HBEA) was applied as isomerization...

The paper presents the experience of using downhole microseismic monitoring to determine the direction of working agent losses while maintaining formation pressure in Baitugan oil field in Orenburg region. Studies were aimed at history matching and elaboration of the further strategy for formation pressure maintenance (FPM) and field development as a whole. The seismic monitoring method was used in the downhole version, when observations are done from the observation well located nearby the injection one. For reliable recording of weak microseismic events, high sensitivity receivers were used with 4 sensors per component. A special injection program was developed. Its first stage consisted in optimization of modes that ensure the maximum injection into formation of a fluid supplied at the wellhead. During acquisition parameter testing, passive recording of the seismic signal was done at all stages of injection during two weeks in various modes, including a short-term stop of injection with subsequent increase in injection to a maximum injection rate with exceeding the fracture gradient. Fracture growth zones were identified below the target formation. Starting from the second week of recording, fracture propagations to the overlying formations were observed under increased injection pressure. Based on data obtained, a three-dimensional map of microseismic events recorded in the formation was created. It was used for interpretation and allowed to specify geometry of self-induced hydraulic fractures depending on injection modes. Microseismic mapping of self-induced fractures in injection wells was done in Russia for the first time. The results of observations allow to optimize the formation pressure maintenance system through optimizing injection modes depending on local fracture gradients and injection shutting off in the zones with uncontrolled self-induced fractures that develop under minimum wellhead pressures. The obtained data also make it possible to significantly improve quality of history matching for carbonate deposits with reduced formation pressure through determining the injection efficiency. This result directly improves both the quality of forecast analysis and economic impact of formation pressure maintenance.

Geothermal resources in Indonesia are commonly located in spread mountain area and some scattered in small islands, such as in Nusa Tenggara and Maluku province. Small scale geothermal power plant with a wellhead type may be required for some geothermal field areas. In operation and maintenance of geothermal power plant usually need high skilled personnel. The real-time monitoring system (RTMS) becomes a promising option for performance analysis and optimization from a remote monitoring room. The performance engineer may execute some small scale power plant in different project sites. The monitoring needs the data variables related significantly to the production of power output. Therefore, finding an attractive-interface, and related variables data of power output, become an interesting issue in performance monitoring. Lahendong organic Rankine cycle (ORC) power plant in North Sulawesi Indonesia, with a capacity of 500 kW, has implemented the RTMS. RTMS data, starting from the sensor reading up to the programmable logic controller (PLC) as a local data collector, transferred to the server (which placed in Germany) via the connection hub. From the server, the data stored on the database and visualize on the human-machine interface (HMI). The variables of the RMTS have been analyzed. The study includes analyzing the scatter-plot of the variables, plotting of the time variables, and applied the Pearson coefficient correlation (PCC) to discover the most related variables to the power output. The variables include brine inlet temperature, brine inlet pressure, hot water inlet temperature, hot water inlet pressure, and power output during the three months. The result, the monitoring of the Lahendong ORC power plant gives positive feedback to the user, with interactive visualization data. The feedback shows that hot water temperature has the most robust correlation to the power output of the Lahendong ORC power plant with 0.91, close to 1 for PCC analysis. In the future, machine learning analysis will be applied to RTMS on Lahendong, so that it will increase user experience and sharpening data analysis. The relocation of the server from Germany to Indonesia will be done to add decision-making features. Expectedly, this paper can be a reference to other power plants and fields that apply RTMS as remote monitoring, taking into consideration the remote location of the geothermal field.