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Metallurgy and Corrosion Control in Oil and Gas Production

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Abstract

This book is intended for engineers and related professionals in the oil and gas production industries. It is intended for use by personnel with limited backgrounds in chemistry, metallurgy, and corrosion and will give them a general understanding of how and why corrosion occurs and the practical approaches to how the effects of corrosion can be mitigated. It is also an asset to the entry-level corrosion control professional who may have a theoretical background in metallurgy, chemistry, or a related field, but who needs to understand the practical limitations of large-scale industrial operations associated with oil and gas production. While the may use by technicians and others with limited formal technical training, it will be written on a level intended for use by engineers having had some exposure to college-level chemistry and some familiarity with materials and engineering design.

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... Thermally Sprayed Aluminum (TSA) coatings are widely used in offshore industry as a long-term corrosion control method (as sacrificial coatings), suitable for structures subjected to temperatures exceeding 120 • C where a minimum of 200 µm thickness is recommended [2][3][4]. Sealer is often recommended for TSA to fill surface-connected porosities resulting from the spraying process and prevent the penetration of corrosive substance within the coating. It has been reported that TSA coatings perform better when sealed with organic or silicone sealers; however, one must note that this will increase the cost of the coating process [3][4][5]. ...
... Sealer is often recommended for TSA to fill surface-connected porosities resulting from the spraying process and prevent the penetration of corrosive substance within the coating. It has been reported that TSA coatings perform better when sealed with organic or silicone sealers; however, one must note that this will increase the cost of the coating process [3][4][5]. Literature also mentions that inadequate sealing and inappropriate TSA thickness can result in blisters and failure of the coating under certain circumstances [3,6]. ...
... It has been reported that TSA coatings perform better when sealed with organic or silicone sealers; however, one must note that this will increase the cost of the coating process [3][4][5]. Literature also mentions that inadequate sealing and inappropriate TSA thickness can result in blisters and failure of the coating under certain circumstances [3,6]. ...
Article
This paper reports the effect of boiling synthetic seawater on the performance of damaged Thermally Sprayed Aluminum (TSA) on carbon steel. Small defects (4% of the sample's geometric surface area) were drilled, exposing the steel, and the performance of the coating was analyzed for corrosion potential for different exposure times (2 h, 335 h, and 5000 h). The samples were monitored using linear polarization resistance (LPR) in order to obtain their corrosion rate. Scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used for post-test characterization. The results showed that a protective layer of Mg(OH) 2 formed in the damaged area, which protected the underlying steel. Additionally, no coating detachment from the steel near the defect region was observed. The corrosion rate was found to be 0.010-0.015 mm/year after 5000 h in boiling synthetic seawater.
... Protective iron carbonate layer often breaks down because of high velocity stream and stresses. In this case, carbonic acid results in localized corrosion under the name " mesa " corrosion because the shape of the damage of the steel surface is similar to the shape of the mountains " Mesa " , California, USA[5]. The following methods of prevention of sweet corrosion are used: injection of corrosion inhibitors (they are not effective at high temperatures); use of martensitic stainless steels (>12% Cr); and control pH by caustic injection. ...
... Carbon steel occupies more than 90% of all the materials in natural gas systems. Drill pipes are used according to the standard API 5D, casings and tubes – API 5CT, and linepipes – API 5L[5]. Design of carbon steel use should be made with calculation of corrosion allowance[32]and suitable heat treatment. ...
... The most common alloy among stainless steel in natural gas systems is 13Cr that is used in wells and in sea water. Generally selection of alloys for use in hot gas wells and other applications occurs in the next direction[5]: carbon steels → stainless steel martensitic 13Cr → → stainless steels austenitic → duplex stainless steels → → austenitic nickel alloys. It is possible to select specific alloy suitable at particular temperature, pressure and CO 2 , H 2 S and NaCl concentrations when the general corrosion rate will be less than 0.05 mm/year[38]. ...
Article
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The aim of this work is to describe and analyze corrosion problems and their solutions in oil, gas, and refining industry. Corrosion phenomena and factors influencing them are discussed. Corrosion control and monitoring methods are illustrated. Corrosion management plays vital role in the solving of corrosion problems. The results are summarized in new book of the author “Corrosion Problems and Solutions in Oil Refining and Petrochemical Industry” published by Springer in 2016.
... The term "produced waters" is used to refer to waters that come from production oil and gas wells [1][2]. As a combination of formation waters and condensates in various proportions, produced waters commonly contain salts, organic acids, carbon dioxide, and other organic compounds. ...
... Produced waters can be very salty, as in oil wells, or almost pure as the condensates of some gas wells. In these two extremes, their corrosivity can be very high due to the presence of chloride ions in the former and of dissolved gases (CO 2 , H 2 S) in the latter [1][2]. It is therefore expected that corrosion due to produced waters can mainly (although not uniquely) affect upstream 1 pipelines and pipelines used to transport them. ...
... In order to successfully model localized corrosion in produced water environments, it is important to define which factors would exert the greatest influence on internal corrosion in pipelines operating under the influence of these conditions. A review of the literature indicates that pH, salts content, conductivity, carbon dioxide partial pressure, organic acids content, and temperature are the factors that provoke the greatest internal damage in upstream pipelines [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. It is a well-known fact that pH is a key factor in internal corrosion mechanisms. ...
Article
A model for the estimation of the time evolution of maximum depth of localized corrosion defects caused under oilfield produced water environments has been developed. It takes into consideration the chemical composition of the produced water and other physical parameters. Immersion tests were conducted using coupons of an API 5L X60 pipeline steel under different experimental conditions and periods. The time dependence of the maximum pit depth was modeled as a power function of time, which was successfully fitted to the obtained experimental data using regression analysis. The main result of this analysis was represented by a holistic model which includes the most important variables involved in the pipeline internal corrosion process in produced waters.
... 'Developed' and 'compliant' are subjective; what is mature for one operator may still be unfamiliar for another; demarcation between non-critical and critical non- compliance may be clear to one operator and less so to the next. These challenges, however, are temporary and can be fixed as much insightful integrity information is available in the public domain [3][4][5][6][7][8][9][10]. ...
... Degradation modes and rates in compliant and non-compliant process environments are well known and have been described in numerous authoritative publications e.g. [3][4][5][6][7][8][9][10]. API RP 581 however, gives little credit for low or zero corrosion rates by the manner in which corrosion rates contribute to the multiplier D. To determine the multiplier for thinning the following procedure is recommended: For uncladded components use the equation below: Art =max[1-( trd-Cr * age)/ (t min+CA),0.0] ...
Conference Paper
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Risk is a term with a multitude of meanings ranging from the subjective to the mathematically exact. The ISO 31000 / Guide 73 broad definition is ‘effect of uncertainty on objectives’ which may be both positive or negative. Quantifying risk, both in absolute or relative sense, relies on the relationship: “Risk is the product of the probability of an event times the consequence of the event”. Used in an absolute sense this relationship produces a figure in the same units as those of the consequence -often a monetary unit – in the period of time considered, e.g. a year. In a relative sense, the equation can be used to judge the change of risk level. For instance, the effect of activities that change the probability of an event, or of measures that change the consequence of an event. In risk management relative risk is an important guide.
... The aggressive conditions encountered in the oil and gas industry require corrosionresistant materials for service in chloride-containing media saturated with hydrogen sulfide and carbon dioxide aqueous solutions, and which contain abrasive particles [1,2]. However, corrosion-resistant steels and alloys are associated with significant capital costs and technical drawbacks; therefore, various types of coatings are becoming increasingly crucial for the oil and gas industry [2]. ...
Article
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The complexity of the operating conditions in oil fields requires the development and use of materials with unique properties. This paper presents the study results for nickel-based coatings fabricated by cold gas spraying. In this study, compositions based on Ni, Ni-Cu, Ni-Zn, Ni-Al2O3/TiC coatings applied to low-alloyed steel bases were investigated. Corrosion resistance was studied by means of electrochemical autoclave testing in simulated oilfield conditions. Hydroabrasive resistance was studied using a unique testing bench. Scanning electron microscopy mappings, microhardness testing, and adhesion testing were used to correlate the results of the tests with the structure, continuity, and porosity of the studied coatings. All the studied coating specimens had a sufficiently high adhesion. The Ni-Zn coating exhibited the lowest corrosion resistance and high hydroabrasive resistance. The Ni-Cu coatings exhibited a high degree of corrosion. The Al2O3/TiC additives gave ambiguous results with respect to the studied properties. Thicknesses of 40–60 microns provided acceptable performance for the studied coatings. Thus, varying the chemical composition the thickness of coatings allows optimal qualities to be obtained for Ni-based coatings made by cold gas spraying for use in the oil and gas industry.
... Unlike general corrosion, where the rate of material removal is typically uniform, slow, and readily detected, pitting corrosion attack is by its nature localised, of rapid growth and represents a major challenge for state-of-the-art of non-destructive inspection techniques [1][2][3]. Localised corrosion affects most predominantly metals and alloys that have passive films, such as stainless steels and high strength aluminium alloys [4]. In carbon-steels, however, pitting can arise where there is a semi-protective film such as mill scale (formed during processing or welding), or due to microbiologically influenced corrosion (MIC) [5]. ...
Article
A microstructural model is presented to assess pit-to-crack transition and corrosion fatigue strength in pitted components. The model is first validated using available experimental data in the literature for pitting corrosion fatigue strength and S-N curves in both carbon and stainless steels. The value of the method proposed and its applicability is then shown by the development of knock down factor maps to the in-air S-N curve. Finally, the influence of pit local topology on pit-to-crack transition damage tolerance and the links to the NDE methods quantitative resolution necessary to account for defect shape or acuity in structural integrity assessments are discussed.
... Capillary tube adalah komponen yang berfungsi mengalirkan larutan kimia ke dalam sumur minyak yang berpotensi membentuk kerak [1]. Komposisi utama larutan kimia tersebut adalah Phosphate (PO 4 ), Chromium (Cr), dan Silica. ...
Article
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Capillary tube adalah komponen yang berfungsi mengalirkan larutan kimia (scale inhibitor) ke dalam sumur minyak yang berpotensi membentuk kerak. Telah terjadi penyumbatan (clogging) dan retak-retak pada komponen capillary tube yang berbahan baja tahan karat austenit 316. Pemasangan komponen tersebut berada dalam satu kesatuan unit dengan komponen lain yang bernama centriline cel flat. Untuk mengetahui lebih lanjut penyebab terjadinya kerusakan, dilakukan serangkaian pemeriksaan dan pengujian. Pemeriksaan tersebut meliputi: data awal dan kronologi, visual, metalografi (makro dan mikro), dan Scanning Electron Microscopy/ Energy Dispersive X-ray Spectroscopy (SEM-EDS). Hasil pemeriksaan menunjukkan adanya penetrasi seng pada permukaan tube. Penetrasi seng yang mencair mencapai batas butir akan membentuk senyawa intermetallic seng-nikel yang akan mengakibatkan terjadinya perubahan fasa austenit menjadi ferit. Perubahan internal stress akibat perubahan volum fasa inilah yang menyebabkan terjadinya retakan di batas butir.Kata kunci: penggetasan logam cair, baja tahan karat austenit, baja galvanis, retakan batas butir
... Some of the researchers have used alloying of Zn, Si, Mg, and rare earth metals with Al using thermal spray process onto the steel substrate and found that the corrosion resistance properties of the coating have increased owing to the deposition of corrosion products in the pores/defects of the coating [23][24][25][26][27][28]. There are many sealants such as organic, inorganic, polymer, ceramic, etc. used to reduce the porosity of the coatings [29][30][31]. The post-treatment of zinc phosphate coated steel substrate with silane provide smooth, crack free, and dense film resulting high corrosion resistance in 3.5 wt.% NaCl solution [32]. ...
Article
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Aluminum coating was deposited by arc thermal spraying process onto the steel substrate for the corrosion protection in aggressive environment. However, the arc thermal sprayed coating possesses defects in the coating. Thus, it is important to reduce the defects and enhance the corrosion resistance properties of the deposited coating using post-treatment. In the present study, we have used different concentrations of sodium phosphate mono basic (NaH2PO4) with 0.1 molar (M) calcium nitrate [Ca(NO3)2] as post-treatment solution to fill out the defects of the Al coating. It was observed by scanning electron microscopy (SEM) that 1 M NaH2PO4 with 0.1 M Ca(NO3)2 treated sample exhibited 71% reduction in defects compared to as coated samples. X-ray diffraction (XRD) was performed to determine the phases formed on the coating surface after treatments. XRD confirms the formation of sodium aluminum hydrogen phosphate (Na3Al(OH)(HPO4)(PO4)) and brushite (Ca(HPO4)(H2O)2) as composite oxides on the Al coating. Electrochemical results show that 0.5 M NaH2PO4 with 0.1 M Ca(NO3)2 treated sample has exhibited the highest charge transfer resistance and the lowest corrosion current density after 89 days of exposure in 3.5 wt.% NaCl solution. The enhancement in corrosion resistance of 0.5 M NaH2PO4 with 0.1 M Ca(NO3)2 treated sample attributed to the formation of adherent, sparingly soluble, and stable corrosion products. The volume fraction result of the corrosion products formed on 0.5 M NaH2PO4 with 0.1 M Ca(NO3)2 treated sample after 89 days of exposure in 3.5 wt.% NaCl using XRD confirms the highest amount of Bayerite (α-Al(OH)3) deposition, thus, the corrosion rate of this sample was the lowest
... In the oil and gas industry, the carbon steels are still the most used alloys. Carbon steels has low cost, good weldability and adequate mechanical strength for most applications in the petrochemical industry, however has low corrosion resistance in several media 4 . Therefore, the knowledge about the corrosion behavior of this steel in contact with different types of petroleum and its interaction can provide valuable information of corrosive agents for each oil. ...
Article
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This work investigates the influence of the physicochemical characteristics of heavy (17.5 °API), medium (28.3 °API) and blend (50% heavy + 50% medium) crude petroleum on corrosion of AISI 1020 carbon steel at 25.0 ± 1.0°C. The corrosion resistance of steel was analyzed by electrochemical impedance spectroscopy, potentiodynamic polarization, and scanning electron microscopy. The electrochemical results and the micrographs show that the corrosion on steel surfaces after contact with the heavy oil is lesser than medium and blend petroleum, although the heavy oil presents a higher amount of total acid number, sulfur compounds and salt. On steel sample immersed in heavy oil, a localized pitting corrosion was identified, while on samples immersed in medium and blend petroleum was found evidence of pitting and alveolar corrosion.
... With reference to pipelines it can be divided into two categories, i) internal and ii) external corrosion. Generally, external sea water corrosion is prevented by the use of an external coating (passive protection) and by sacrificial anodes or active protection (Heidersbach, 2011). The performance of such protection measures is quite satisfactory . ...
Conference Paper
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Continuous improvements in the Oil&Gas industry to deal with reliability and maintainability objectives, higher operational reliability, improved safety, and emergency readiness for potential risk of unexpected events have led offshore companies to be in the forefront of development of design and analysis methodologies for integrity assessment and safety operations. The architecture of an integrated model targeting the major residual risks to the asset, new generations of internal and external inspection techniques, real-time monitoring sensors, material degradation prediction related to the actual and future operational conditions and machine learning methods are, as identified from the experiences of the authors, the new frontiers for Pipeline Integrity Management. The advance in automation processes to build pipeline digital twins, looking at new predictive and diagnosis tools by advanced FE models, allows not only to think defensively but also to take an aggressive position toward safety and asset optimization. In this paper, much attention is devoted to the inspection and operational data deriving from 40 years of pipeline integrity assessment from which engineering assessment can benefit. A suite of services for an integrated solution, including ad-hoc engineering and repair system readiness, is identified as the main pillar for best-in-class operators. Finally, case histories and integrated solutions to ensure satisfactory performance and safety are discussed.
... Some properties of the pigments were evaluated and listed in Table 2 such as hydrogen ion concentration (pH), color, oil absorption, specific gravity, matter soluble in water, and volatile matter. [32,33] It is clear that the oil absorption value of ZP and IWP is about 4.65 and 13.95 (g/100 g), respectively. This low value of oil absorption indicates the economic endurance as pigment materials because of their low consuming of binder without affecting properties like interstitial bonding of the paint, gloss, and dispersion. ...
Article
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The purpose of this article was to evaluate the performance of a poly(aniline‐co‐anisidine)/iron waste composite (COIW) as an anticorrosive pigment for primer coatings. A procedure was outlined to prepare COIW and evaluate its anticorrosive properties following the electrochemical behavior and corrosion test of the coated steel. Various zinc‐rich epoxy primers were formulated by replacing part of the zinc powder (ZP) pigment with COIW. In all formulas, the ratio of pigment to epoxy resin was fixed at 2. In the pigment mix, the percentage of COIW was ranged from 5% to 60% by weight to the ZP. The performance of the formulated primers was estimated by the salt immersion test and potentiodynamic polarization measurement (corrosion potential, polarization resistance, and corrosion rate essays). It was demonstrated that COIW is effective in protecting steel from corrosion when it is used in combination with ZP.
... This is one of the serious problems being faced by many industries and is responsible for multibillion-dollar losses due to premature equipment failures [1]. Erosion corrosion is ranked as the 5th most common degradation issue in fluid handling systems (pumps, compressors, piping systems in offshore oil/gas facilities, desalination plants, etc.) and has direct consequences in terms of equipment safety [2][3][4][5][6]. This problem gets more aggravated by the presence of high amounts of solid/sand particles of different morphologies in the flowing fluid [7,8]. ...
Article
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Erosion corrosion performance of API 5L-X65 carbon steel was investigated at three different impingement velocities (3, 6 & 12 m/s), five different angles (15, 30, 45, 60, & 90°), and with/without solid particles (average particle size of 314 µm). The experiments were conducted in 0.2 M NaCl solution at room temperature for a duration of 24 h and the results showed that the maximum erosion corrosion rate was observed at 45° irrespective of the velocity. The highest erosion corrosion rate at 45° was due to the balance between the shear and normal impact stress at this angle. Ploughing, deep craters, and micro-forging/plastic deformation were found to be the main erosion corrosion mechanisms. The maximum wear scar depth measured using optical profilometery was found to be 51 µm (average) at an impingement angle of 45°.
... The choice of X80 steel was motivated by its widespread application in construction of casings, tubing, pipe works and transport lines in the oil and gas industry. [8][9][10][11][12][13][14] On the other hand, the choice of Griffonia simplicifolia is due to the broad alkaloid composition which has been reported about the plant, especially the presence of 5hydroxytryptophan. 15 Experimental Steel samples and surface preparation X80 steel samples were purchased from Qingdao Tengxiang Instrument and Equipment Co. Ltd., China and were cut into coupons of dimension 2 cm x 2 cm for thermogravimetric experiments and 1 cm x 1 cm for electrochemical studies. ...
... [8,20,21]. In the meantime, grooving corrosion is a form of weld metal corrosion in the welded joint, and the grooving corrosion susceptibility coefficient is used to evaluate corrosion resistance of weld metal relative to base metal [22][23][24]. Therefore, it is necessary to ascertain the reason for the welded joint grooving corrosion behavior and provide a guide for the engineering application.It is widely believed that the grooving corrosion is related to the difference of carbon content, microstructure and alloying metal, causing the different corrosion behaviors between the welded zone and other zones in the electrolyte [10][11][12]. ...
Article
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Corrosion behavior of a welded joint is complicated and can be strongly dependent on its local chemical composition and microstructure of the surface. To gain a thorough insight into the grooving corrosion behavior of welded joint, it is necessary to understand the corrosion mechanism of different regions of the welded joint. In this study, the influence of the lattice constant on the electron work function (EWF) and corrosion rate of base metal and two weld metals was investigated using a constant potential polarization approach and a scanning Kelvin probe (SKP). Experimental results showed that surface EWF decreased with increasing lattice constant, whereas the corrosion rate increased with an increase in lattice constant. At the same time, it was theoretically demonstrated that the lattice constant can affect the local EWF fluctuation of a welded joint. The fluctuation further leads to the corrosion rate difference of the different regions of the welded joint. So, the lattice constant change in the surface structure is a possible reason for the average grooving susceptibility coefficient difference of two kinds of welded joint. Besides, the alloying elements distribution of two kinds of welded joint zones should be a main reason for the average grooving susceptibility coefficient difference of joints verified by the EPMA measurements and the quantitative calculatinon of the contents of Cu, Ni and Si in the joints.
... To achieve other desired properties such as resistance to corrosion and reduced weight, trace amounts of other elements like chromium, sulphur, phosphorus, and manganese can be added to iron to obtain steel of different grades. Such steel grades like API 5L X70, X80, X60, X65, X52 and X42 have now been extensively preferred for line pipe applications (Heidersbach, 2010, Kennedy, 1993Siciliano et al., 2008). Others include API-5CT J55, J55N, N80-P110 and K55 for welded casing and tubing pipes and low carbon steel or mild steel for pipework and storage facility construction (Smith, 1999;Ueda et al., 2000). ...
Article
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Corrosion of X80 steel was investigated in simulated acidizing fluids containing different concentrations of 3-(2-chloro-5,6-dihydrobenzo[b][1]benzazepin-11-yl)-N,N-dimethylpropan-1-amine (3CDA) at different temperatures using weight loss and electrochemical techniques. X80 steel corroded at higher rates in the uninhibited acid solution than in the inhibited solutions. Inhibition efficiency of 3CDA was highest (88.8 %) at 10x10-5 M concentration at 30 oC and decreased as temperature decreased. Some intensifiers were added to improve the inhibition efficiency at high temperatures. The 3CDA acts as mixed type inhibitor and adsorbs spontaneously on steel surface by physical and chemical interactive forces. Techniques such as FTIR, SEM and EDAX were also employed to characterize the potential of 3CDA as efficient steel corrosion inhibitor for oilfield application.
... Materials selection of corrosion resistant grades of steel is aimed at reducing corrosion problems. Such steel grades like API 5L X70, X80, X60, X65, X52 and X42 have now been extensively preferred for line pipe applications [2,6,7]. Others include API-5CT J55, J55N, N80-P110, and K55 for welded casing and tubing pipes and mild steel for pipework and storage facility construction [8,9] . ...
... H2S present in NG oil wells, generates sour gas and corrosion problems. NG also contains CO2 which converts into carbonic acid (H2CO3) when it comes into contact with moisture and sometimes forms carbonate scales in wells casings 5,7 . Wet acid gas, composed of a mixture of H2S, CO2, and water separated from offshore oil wells, is strongly corrosive to carbon steel (CS). ...
Corrosion is a worldwide, crucial problem that strongly affects natural and industrial environments, in particular the oil and gas industry. Natural gas (NG) is a source of energy in industrial, residential, commercial and electric applications. The abundance of NG in many countries augurs a profitable situation for the vast energy industry. NG is considered friendlier to the environment and with lesser greenhouse gas emissions as compared with other fossil fuels. In the last years, shale gas is increasingly exploited in U.S. and Europe, applying a hydraulic fracturing technique, for releasing gas from the bed rock by injection of saline water, acidic chemicals and sand to the wells. Various critical sectors of the NG industry infrastructure suffer from several types of corrosion: steel casings of production wells and their drilling equipment; gas conveying pipelines including pumps and valves; plants for regasification of liquefied natural gas (LNG) and municipal networks of NG distribution to the consumers. Practical technologies that minimize or prevent corrosion include selection of corrosion resistant engineering materials, cathodic protection, corrosion inhibitors, and application of external and internal paints, coatings and linings. Mexico is undergoing an intense reform process of the energy sector, that involves its oil, NG and electricity industries. Typical cases of corrosion management in the NG industry are presented based on the authors experience and knowledge.
... Corrosão em placas: localizadas em regiões específicas da superfície, conforme Figura 5; Corrosão alveolar: em forma de sulcos ou escavações, conforme Figura 6; Corrosão puntiforme ou por pite: se processa em pontos ou pequenas área localizadas na superfície, conforme Figura 7. 2.2. Corrosão quanto à fenomenologia De acordo com a sua fenomenologia (ou processo corrosivo), conforme já mencionado, pode-se classificar a corrosão em oito grupos básicos [4, 6, 7]. São eles: Galvânica ou bimetálica: quando metais dissimilares são imersos em uma solução corrosiva ou condutora, existe uma diferença de potencial entre os metais. ...
Article
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A integridade de materiais e equipamentos em ambientes com presença de dióxido de carbono (CO2) e sulfeto de hidrogênio (H2S) é uma das principais preocupações na produção do petróleo da chamada camada do pré-sal. Isto porque o CO2 e o H2S estão geralmente associados com a corrosão interna de instalações de petróleo e gás natural. E como estes dois gases estão presentes em teores elevados nos reservatórios do pré-sal, o ataque corrosivo se constitui num sério problema para a produção e transporte do grande volume de petróleo e gás ali presentes. Uma vez que o dióxido de carbono já é considerado o principal agente corrosivo desta importante província petrolífera, apresentaremos alguns tópicos relacionados ao processo corrosivo por CO2, para os tubos de produção de petróleo localizados no pré-sal da costa brasileira.
Article
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Fundamental theory and methods are investigated of inspecting tubing and casing simultaneously using pulsed eddy current testing by numerical simulations and experiments. The distribution and variation of eddy current field are given in the finite element simulation for the inspection of undamaged and corroded casing and tubing combinations, with tubing outer diameter 73.8 mm, wall thickness 5.7 mm, corrosion depth 1.25 mm, 2.5 mm, 3.75 mm, and casing outer diameter 141.5 mm, wall thickness 7.7 mm, corrosion depth 1.25 mm, 2.5 mm, and 3.75 mm, respectively. The results show that eddy current field propagates around and to the depth after the direct section of the exciting current is cut off and the intensity center of eddy current field shifts gradually from the inner side of the tubing to the casing, which forms the basis of analyzing inspection mechanism. Corrosion at a particular depth is related to a particular optimum time slice of the induced voltage (namely with deepest concave) and a highest sensitivity is obtained at this slice. The time associated with this slice is in accordance with the time when the intensity center of eddy current reaches the corrosion. Corrosion at different depths has different voltage time slices starting to show signal of defect, which can be used to estimate the depth of the defect in order to judge the defect coming from tubing or casing. Furthermore, sinking degree of the time slice reflects the size of the defect. All machined defects can be recognized in the experiments and the optimum time slice appears at 0.01 s and 0.008 s after the excitation current is cut off for the tubing corrosion of 1.25 mm and 2.5 mm, respectively. The optimum time slice appears at the last moment of cut-off period, 0.625, for the casing corrosion. Experimental results agree well with the simulations and show the existence of the optimum correspondence between depth of corrosion and starting time of the defect signal of time slice, relations between sinking degree of the time slice, and corrosion size.
Conference Paper
Corrosion is a problem that must be handled in a construction plan. One way to overcome this is by predicting the corrosion rate of material under certain conditions. This study aims to determine the corrosion rate of mild steel welded joints using acid and alkaline solution media. The specimens are made from ST37 mild steel which is welded together. The specimens were divided into two, namely specimens that were not subjected to post-weld heat treatment (PWHT) and specimens subjected to post-weld heat treatment (PWHT). The specimens were immersed in an acid solution, namely 3% KCl and an alkaline solution, namely 10% NaOH for 100 hours, 200 hours, 300 hours, and 400 hours. The 3% KCl solution’s corrosion rate had an upward trend, starting from 0.092 mmpy at 100 hours of immersion time to 0.16 mmpy at 400 hours of immersion time. The corrosion rate of 3% KCl is in a good category. In alkaline solutions, the corrosion rate trends to be constant, which is in the range of 0.01 mmpy to 0.024 mmpy. The corrosion rate at 10% NaOH is included in the excellent category. Specimens with a post-weld heat treatment (PWHT) process have a lower corrosion rate than those without a post-weld heat treatment (PWHT) process. A 3% KCl acid solution’s corrosion rate was higher than the corrosion rate of 10% NaOH alkaline solution.
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In this paper, newly synthesized pyridinone derivatives namely; 6-amino-2-oxo-1-(((1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl) methylene) amino)-4-(thiophen-2-yl)-1,2-dihydropyridine-3,5-dicarbo- nitrile (II) and 6-amino-1-(((2-chloro-7-ethoxyquinnolin-3-yl) methylene) amino)-2-oxo-4-(thiophen-2-yl)-1,2-dihydropyridine-3,5-dicarbonitrile (III) were synthesized in laboratory and their chemical structure were characterized via elemental analysis, FTIR, ¹ H- and ¹³ C -NMR spectroscopic analysis tools. The performance of the newly synthesized pyridinone derivatives as anticorrosion for carbon steel alloys in 2 M HCl aggressive medium were carried out using weight loss measurement as chemical testing method, in addition to PDP and EIS as electrochemical measurements. The collected data revealed that these pyridinone derivatives operated as excellent anticorrosion for metallic structures. PDP results revealed that these pyridinone derivatives behave as mixed type inhibitors. The adsorption isotherm revealed that undertaken compounds obeyed Langmuir adsorption isotherm. EIS data confirmed that the values charge transfer resistance (R ct ) was increased by increasing the concentration of the injected inhibitor molecules, while the electrochemical double layer (C dl ) was dramatically decreased. The work was supported by two surface analysis methods such as SEM and EDX. Finally, a suitable inhibition mechanism was assumed and discussed in details.
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The applications of advanced ceramics, composites and coatings in mineral, mining, fuel production and processing are reviewed. The materials include oxide and non‐oxide ceramics (specifically SiC‐based), ceramic‐ceramic and ceramic‐metal composites, coatings on metallic components where functional application properties can be achieved. Some principles of materials selection, specifically for erosion wear and corrosion applications, and manufacturing are considered. The examples of the successful development and processing of ceramics, coatings and composites with manageable structures and phase compositions, in the erosion related applications, particularly conducted by the author, are discussed and reviewed. Specifically, industrially employed types of ceramics and processing routes were focused on the considered applications. Particular demands for advanced materials with high reliability and complex shapes or for protective coatings on complex shape steel components and long tubing with inner surface protection require novel and optimized processing. The factors affecting erosion and erosion‐corrosion resistance and the paths for the erosion resistance enhancement of ceramic and coating materials are considered. Ceramic components design, technology and installation features are reviewed. This article is protected by copyright. All rights reserved
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In the past decade, oil and gas exploration has led to increased oil field shutdowns and equipment failures due to chemical reactions between steel and corrosive environments, which has caused severe corrosion in the oil and gas industry. Oil and gas reservoirs are endangered by corrosion, which not only leads to economic losses but also compromises security and safety. The most desirable alloy should therefore be composed of a strong, corrosion-resistant, cost-effective, and mechanically suitable material in upstream oil and gas application. Stainless steel with a 13% chromium content was tested in order to determine whether hydrogen sulfide (H2S) could cause corrosion on this alloy, which is used for sour oil wells that contain hydrogen sulfide. In accordance with conventional electrochemical analysis methods, a series of experiments were performed in order to investigate the effects of temperature, pH, and immersion time on corrosion behavior of 13% Cr stainless steel in a H2S environment. The polarization resistance technique such as Tafel Plots was used to monitor corrosion. The crystal structure of corrosion products was studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). This study found that the pH and temperature of an environment influence the formation of a film on steel surfaces. Steel becomes more resistant to corrosion as the temperature and pH decreases and thick and uniform protective films form. A significant impact of environmental parameters on corrosion behaviour is demonstrated in this study.
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This review paper discusses the research work published in the last decade on the use of organic compounds and natural products as corrosion inhibitors for steel in CO2 and CO2/H2S coexisting environments. The carbon and mild steel samples tested are mostly immersed in CO2-saturated NaCl/brine solutions or simulated oilfield waters. The influence of temperature, immersion time, CO2 partial pressure, pre-corrosion, flow rate/rotation speed, and the synergistic effect of other compounds on the corrosion inhibition effectiveness of organic compounds and natural products is presented. Primarily, weight loss and electrochemical techniques were used to evaluate the corrosion inhibition effectiveness of these compounds.
Chapter
Water processing system in Iraq Ah Oilfield suffered a lot from corrosion affects like pipeline, tank, flange, valve leakage from 2015 to 2018. That caused both loss and pollution over 100 times one year. In order to solve this problem, phenomenon was checked and statistics, observation and laboratory test were carried out. After researching all the possible factors like Cl⁻¹, pH, Fe²⁺, DO, SRB, CO⁻², H2S, fluid flow velocity, suspended pollutant combined with laboratory results, it is confirmed H2S and SRB are the two main causes of pitting corrosion. The mechanism is that H2S (over 100 ppm) in produced water reacts with Fe, creating FeS scale. SRB accelerates the corrosion between FeS scale and steel. The maximum pitting corrosion rate can reach to 0.7 mm/y.
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The objective of this work was to investigate the cause of failed pipeline steel, in particular at its weld area which may due to the preferential corrosion. The pipeline sample was supplied by an industry based in Miri, Sarawak. The serious circumstances in the piping scheme led to high-level corrosion of the inner surface, particularly in the weld region. Inside the pipe system, natural gas flowed into the processing operation within the platform. Several tests and experiments were elucidated to comprehend the metallographic of the failure portion in order to explore the failure. Pipe sample testing techniques such as visual inspection, optical microscope, scanning electron microscope, and Vickers hardness testing were carried out effectively. The characterization of the microstructure was carried out on the sample taken from three main regions of the sample, which are the base metal, the heat affected area and also the weld joint, in order to elaborate the difference of the properties. The test outcome has shown that corrosion occurred at the pipe, even though the pipe system used cathodic protection.
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“VKO “Simvol” designs and produces marking equipment, reading equipment and traceability software. Fluorescent dot-peen marking (FDMP) is an improved version of dot peen marking (DPM) technology. In FDPM technology information dots are filled with special material – fluorescent composition. Various fluorescent compositions provide high stability of marking in different aggressive media, such as moisture, salt and acid solutions, oils, lubricants or high temperatures. 2D barcode Data Matrix makes the marking machine readable, even if some of the dots are damaged.
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In the process of evaluating the quality of a batch of 125S casing for oil and gas wells, it was found that the mechanical properties of different casing bodies in the same batch were significantly different, and the fluctuation range of yield strength was up to 60 MPa. The steel pipe with the lowest yield strength was not satisfied according to the technical standards. In order to study the causes of the uneven tensile properties, the chemical composition analysis, tensile tests, Charpy impact tests, Rockwell hardness tests and metallographic analysis were investigated for the two casings of this batch. Through the analysis of the test results, it is found that the chemical composition and metallographic structure of this batch of casing were conforming to with the design requirements, and the materials possessed high toughness. The problem of non-uniform performance of this batch casing was generated from the heat treatment stage during the production process. The excessive tempering temperature caused the reduction of material strength.
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A novel tuning‐fork test method was developed to study hydrogen‐induced stress corrosion cracking of high‐strength steels. Special tuning‐fork specimens are designed to enable accurate stress adjustment via constant displacement under cathodic hydrogen charging conditions. In this study, the testing method is further developed, making the potentiostatic hydrogen charging possible through the modifications of the corrosion cell. Different direct‐quenched, low‐ and medium‐carbon steel grades, with a hardness range of 300–550 HBW, are investigated with both galvanostatic and potentiostatic hydrogen charging techniques. For each steel grade, the lowest fracture stress and highest no‐fracture stress are determined. Both hydrogen charging techniques produce similar results, and it is observed that the fracture stress decreases with the increase in hardness. However, the potentiostatic technique produces larger differences between the lowest fracture stress results, thus having a better resolution.
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In an injection well, sacrificial anode protectors were installed in order to protect the tubing string. However, one sacrificial anode protector was broken during the lifting process of the tubing string in well workover. The causes for the fracture failure of the sacrificial anode protector were investigated by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffractometry (XRD) and optical microscope (OM). The metallographic structure of the sacrificial anode protector was pearlite plus reticular ferrite and its chemical composition met the requirements of API Spec 5CT. However, the hardness distribution was inhomogeneous and the yield strength was also lower than the required value. In addition, the impact toughness was poor. The failure of the sacrificial anode protector was the combined consequence of material defects and the harsh service environment. In the CO2/H2S environment, the anode was dissolved and the cathode was subjected to hydrogen evolution. Therefore, hydrogen atoms diffused into the metal and accumulated at crystal defects, thus inducing microcracks. Finally, hydrogen embrittlement fracture failure occurred. In the material selection of the cathode of the sacrificial anode protector, a material with good hydrogen resistance is recommended and the high-temperature exposure time should be prolonged. In addition, it is necessary to design an effective service life for the sacrificial anode protector and replace the sacrificial anode protector in time.
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The vapor phase corrosion inhibitors (VPCIs), also called volatile corrosion inhibitors, are a potential corrosion prevention strategy. This chapter describes the basics and fundamentals of VPCI, their classification according to the protection mechanism, and their chemical nature and composition. VPCIs are employed in diverse forms, e.g. powders, pellets, aqueous or solvent solutions, impregnated papers, and closed in pouches and sachets, and added to coatings, paints, and films. Magna International, with headquarters in Singapore, has developed and implemented vapor biocorrosion inhibitors.
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One of the methods used for the secondary exploitation of oil deposits is the water injection. The injected water is obtained after the separation of the well extracted fluid that contains a mixture of crude oil, water, gases and solid particles. Prior to injection, water must meet the following requirements: a high degree of purity obtained thought the lowest possible mechanical and oil content; lower degree of aggressiveness (corrosion); the highest stability; compatibility with the fluids and minerals in the reservoir formation; low oxygen content and bacteria. The fulfilment of these requirements must be ensured by the water treatment plant whose equipment is subjected to corrosion wear. The equipment degradation are occurring mainly at pipelines and connecting elements of the flotation skid, in the form of advanced corrosion wear because the water injection contains an inconsistent composition mixture of dissolved gases, hydrocarbons, solid particles. The paper presents the regression analyses that emphasize the influence of chemical water composition and fluid speed on the corrosion rate of the different equipment parts. The corrosion rates were obtained using metallic samples according with the NACE SP0775-2013 standard that were placed in different points of the plant. The paper results can be used both at the water plant exploitation and also to next studies concerning the effectiveness of the corrosion inhibition on the corrosion rate.
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In this article has studied the negative roles of chlorides, dissolved oxygen and aluminum, which are existed directly in the oil or indirectly in the associated water on the corrosion resistance of the coiled-pipes of the tubular furnace inside KINEF refinery (Russia). In this paper, we studied the coiled-pipes of the ELOU-AVT-6 installation, which are subjected to severe destruction, and as a result, they are prematurely failed due to the negative effects of the studied impurities, which led to decrease their service life and the quality of oil products.
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Brine from desalination plants is an upcoming environmental threat to aquatic ecosystems. Multi‐effect distillation with thermal vapor compression (MED‐TVC) is proposed to treat desalination brine solutions of more than 70 000 mg/L of total dissolved solids (TDS). To achieve this, an integrated techno‐economic model consisting of three submodels (scaling prediction, mathematical, and economic) is developed and a techno‐economic assessment of a 10 m³/d MED‐TVC system is presented under two different scenarios. In this respect, various sensitivity analyses were performed, revealing that the 4‐effect MED‐TVC system operating at 120°C feed steam presents the lowest freshwater cost (US$3.00/m³) and the lowest payback period (3.04 years) under the first scenario, whereas the 2‐effect MED‐TVC system operating at 120°C feed steam presents the lowest freshwater cost (US$1.69/m³) and the lowest payback period (1.71 years) under the second scenario of waste heat utilization. Exergy analysis for these optimal systems revealed that the exergy efficiency of the optimal system in the second scenario (4.36%) is higher than in the first scenario (4.21%). For both optimal systems, the exergy destruction in the TVC unit and in the effects accounts for more than 79% of the total exergy destruction. Moreover, it was found that thermal energy costs contribute significantly to the costs and affect the design procedure. Scaling up the optimal systems for freshwater production by more than 190 m³/d, freshwater cost becomes constant and can be reduced by up to 50% with waste heat integration. Considering the high quality of the freshwater produced, MED‐TVC process can be profitable due to the revenue from the sale of the freshwater. Overall, the results suggest that the MED‐TVC process for brine treatment is economically feasible.
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The problem of premature failure of bearings is a common type of failure. In most cases, the destruction occurs due to violation of operating conditions. Since the destruction of bearings is a frequent occurrence, consideration of this special case of destruction in the future will help to avoid such problems. The object of research is the screw compressor bearings destroyed during operation. To identify the causes, a collapsed bearing was examined and a bearing that did not collapse during operation.
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The coatings deposited by arc thermal spraying process possess defects and pores within the coating, which must be filled using a proper pore sealing agent. In the present study, we have deposited an Al coating on a steel substrate using arc thermal spraying. Post-treatment with different concentrations of sodium phosphate monobasic (NaH2PO4) salt solution was then carried out to fill the pores in the Al coating. The scanning electron microscopy results show that NaH2PO4 (SP) at 0.5 M concentration significantly reduces the porosity. When the concentration of NaH2PO4 is less than 0.5 M, the coating contains some pores and defects, whereas post-treatment with 1 M NaH2PO4 leads to the formation of a brittle film with wide cracks on the coating surface. The x-ray diffraction results of the treated coating confirm the formation of sodium aluminum hydrogen phosphate (Na3Al(OH)(HPO4)(PO4) film (SAHP). Electrochemical results obtained in artificial ocean water solution (ASTM D1141) show that treatment of the coating with 0.5 M NaH2PO4 enhanced the corrosion resistance properties for up to 7 days of exposure, but once the exposure periods are extended, the treated coatings exhibited deterioration because SAHP film started to dissolve in aggressive ions, i.e., artificial ocean water solution which makes the solution acidic owing to the formation of hydrogen phosphate and phosphoric acid. The AC sample shows protection after 60 days of exposure in artificial ocean water solution owing to the formation of protective, adherent, and uniform α-Al(OH)3 as corrosion products.
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There is an increasing demand from oil and gas industry to ensure the integrity of assets and the enviroment in the critical conditions found in presalt wells. This study evaluates new formulations of corrosion inhibitors with different types and alkoxylation degrees of nitrogen‐based inhibitors to assess corrosion behavior of carbon steel (API X65). For these studies, corrosion rates were determined through measurements of weight loss and linear polarization resistance (LPR). In the case of electrochemical measurements, experiments were carried out in a laminar flow and in a turbulent flow regime. All data were collected in the presence of CO2 and CO2/H2S mixtures. The results revealed that corrosion protection of carbon steel critically depends on the nitrogen‐based inhibitor's alkoxylation type and degree as well as the condition to which they are exposed. It was possible to notice that an ethoxylated amine whose inhibition efficiency in the presence of CO2 was about 10%, when exposed to H2S environment at the same temperature showed an efficiency of 86%. It was also observed that the inhibitor with a higher ethoxylation degree presented better efficiencies than the one with a lower degree. New formulations of corrosion inhibitors with different types and alkoxylation degrees of nitrogen‐based inhibitors were evaluated to assess corrosion behavior of carbon steel. Corrosion rates were determined through measurements of weight loss and linear polarization resistance. In the case of electrochemical measurements, experiments were carried out in a laminar flow and in a turbulent flow regime.
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Lucinda Jetty was one of the first concrete structures in Australia to be identified with alkali-silica reaction (ASR). The prestressed concrete girders underwent cracking soon after construction and have been the subject of detailed investigations and monitoring since the late 1980s. The atmospherically exposed jetty roadway girders still show adequate serviceability despite ASR. However, girders at the jetty abutment are subject to constant seawater splash and have recently been found to suffer extensive corrosion of prestressing strands and stirrups, in addition to a higher degree of ASR damage. This paper examines the long-term performance of ASR-affected prestressed concrete in an aggressive marine environment and the interrelationships between ASR and corrosion.
Chapter
This chapter briefly describes an approach to optimise materials for both production and injection systems focusing on environmental and operational parameters, bearing in mind whole life costing. Past successes in effective use of carbon and low alloy steels (CLASs) are included, highlighting key enabling criteria, allowing extended use of these alloys. A brief overview of the elements of production facilities is given with a view to outlining the materials selection route for each application. CLASs with continuous corrosion inhibition are normally acceptable options for gas treating plants. The chapter briefly describes the primary alloy systems used in hydrocarbon production. Whole life cost analysis provides the best means by which capital expenditure is optimised to offer the highest rate of return on investment. A materials optimisation strategy requires the integration of key parameters to allow the selection of the most suitable, safe, and economical material option and corrosion control procedure.
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Oilfield produced brine can cause significant corrosion and mineral scaling issues to the production system and the environment. Solution alkalinity is an important parameter dictating the corrosion and scaling threat of oilfield brine. However, it remains an ongoing challenge to accurately measure oilfield brine alkalinity, especially in the presence of weak organic acids, such as carboxylic acids. Conventional titration method for oilfield alkalinity measurement does not consider the impact of organic acid on alkalinity, leading to an erroneous measurement result. In this study, an analytical method was presented to simultaneously measure total alkalinity and weak organic acid (acetic acid) concentrations of the brine via an automated titration approach. It shows that the automated method substantially outperformed the conventional method in terms of accurately measuring both solution alkalinity and organic acid concentration with one titration effort. The automated analytical method is considerably robust and is not highly sensitive to the introduction of random error. Modeling calculation shows that the automated analytical method exceeds the conventional method in determining solution alkalinity with an enhanced accuracy for scale threat predictions. This is the first study to report such an accurate and convenient analytical method to measure solution alkalinity and organic acid concentrations for oilfield produced brine. Given the accuracy and convenience of this reported analytical method, this method can find wide industrial applications within oilfield and beyond, including corrosion and scaling control, water resources management and environmental pollution control.
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Enhanced Oil Recovery (EOR) program to increase oil production from mature fields are now being implemented in Indonesia amid concern over the continuous decrease of oil production level. The mature fields and EOR process have the tendency to carry relatively high impurities components (CO2, H2S, chloride ions) that results in early corrosion occurrence, creating damages in the subsurface equipment (wellhead, tubing, Xmas tree, etc). In Java area with 0.09 TSCF potential gas reserves, 49.3 MMSTB oil and + 23% CO2 content, such amount of CO2 gas and possibility of H2S and chloride from the reservoir will require a higher grade material than the conventional carbon steel. This paper discuss the preliminary materials selection process in the program plan based on the existing condition. The material selection based on the evaluation of closest field data, literature review as a comparison, material, and fluid analysis test. Duplex 22Cr-15 Cr materials are the main study in the paper as the candidate for the tubing material in high CO2, high H2S and chloride environment. The polarization result in 27°C and 50°C showed that the chrome 22 %Cr material had pitting tendency in chloride ion 25,000 ppm, while at high temperature (80 °C) the pitting tendency shifted to 5,000 ppm of chloride ion.
Article
This paper presents a novel TFT (tuning fork test) stress corrosion testing method, which was developed for classifying martensitic high‐strength steels. The novel method was developed by applying finite element calculations to optimize a tuning fork geometry to enable accurate stress adjustment with simple inexpensive equipment. Different steels were exposed to cathodic hydrogen charging conditions with various elastic tensile stress levels that were achieved by displacement control. All steels exhibited hydrogen‐induced stress corrosion cracking after exceeding a material‐specific threshold stress level that decreased linearly with increasing hardness. A novel testing method was developed to study the SCC susceptibility of high‐strength steels. The susceptibility of direct‐quenched abrasion‐resistant steels was evaluated with relative threshold stress level. The results demonstrated a linear relationship between steel hardness and relative threshold stress level over the hardness range of 450–600 HBW.
Chapter
This chapter is concerned with the chemistry of metals, their salts and other inorganic compounds as applied in the upstream oil and gas industry. It is also mainly concerned with metal salts of sodium, potassium and lithium although some cesium salts are also considered. The chapter examines the relatively simple and mostly inorganic salts of alkali metals. A restricted number of barium salts are utilised and encountered in the upstream oil and gas sector, and these are primarily barium sulphate and barium chloride. The chapter also examines the use of a variety of chemical compounds in the oil and gas industry based on halogens. A number of other metals, metal salts and complexes, inorganics and other related compounds are or have been used in the upstream oil and gas industry. The chapter describes a number of biological factors and environmental impacts relating to metals. It considers the importance of bioavailability, toxicity and biodegradation.
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The main purpose of this research was to establish the effectiveness of the V844* corrosion inhibitor for seawater on various metallic materials: carbon steel, aluminum and copper alloy at different concentrations via colloid formation. The changes in both physical and chemical properties of seawater, including pH, total hardness, alkalinity, total dissolved solids (TDS) and conductivity at different concentrations of V844 were assessed, too. The test procedure involves dissolving the V844 corrosion inhibitor (CI) powder provided by Magna International Private Limited in seawater to obtain a stock solution of 4% V844 in seawater, which was further diluted to obtain the remaining concentrations. The analysis of parameters begun when various metal species, polished beforehand, were placed into the solutions. The analysis was observed over a period of 26 days and a total of 9 sets of readings were obtained. From our observation and ear power stations burning fossil-fuels generating acidic rains, the pH can diminish to 6.
Article
Purpose This paper aims to provide an insight into the main parameters that govern corrosion mechanisms in production tubing of oil and gas wells. Design/methodology/approach Corrosion has been an old concern for the oil industry. None of the three major sectors of the oil industry, namely, upstream, midstream and downstream, are immune of corrosion attacks. However, the upstream sector (oil and gas production facilities) is more vulnerable to corrosion because of its extreme conditions such as high temperature and pressure, multiphase flow, complicated water chemistry, presence of acidic gases, etc. This paper is a general review of the influence of such parameters on corrosion mechanisms of oil and gas wells. Findings In recent years, many technical papers have been published in this area. However, none of them provide a general review of the all contributing parameters on corrosion under field conditions. Originality value Modeling and corrosion mitigating processes under downhole conditions require a thorough understanding of the influencing parameters. This paper aims to provide an insight into the main parameters that govern corrosion mechanisms in production tubing of oil and gas wells.
Conference Paper
Corrosion inhibitors are widely used to guarantee asset integrity from oil exploration and production stages (e.g. drilling equipment and metal piping in producing wells) to refinery, as well as during transportation of produced fluids and finished by-products. The major forms of corrosion found among the oil and gas industry include chemical, electrochemical, mechanical, and microbiologically induced. Corrosion inhibition by organic compounds is applied mostly in electrochemical corrosion due to acidic gases (H2S and CO2), from which CO2 corrosion is considered one of the major threats in oil and gas producing assets. According to the literature, amide and amine/diamine are the main classes of corrosion inhibitors used to combat sweet corrosion (CO2) in oilfields. However, the constant need to overcome new challenges makes it possible to create novel chemicals or to identify well-known molecules that can be improved in order to meet both the market demands and technical requirements, for example: guaranteed inhibitory capacity under several conditions, low emulsion and foaming tendency. In the present work, evaluations of different alkoxylation degrees and types of diamines were carried out in order to analyze the influence on the corrosion behavior of a carbon steel surface (SAE 1020 and API 5L X65), as well as emulsion and foaming tendencies. For these studies, the corrosion measurements were either performed by linear polarization resistance (LPR) or by weight loss measurements. The data revealed that their corrosion protection of carbon steel depended critically on the alkoxylation type and degree. Therefore, a suitable choice of molecule can create a tailor-made product to achieve specific requirements. The chemicals developed have shown good corrosion inhibiton performance and have satisfied defined pratical requirements to avoid emulsion and foaming tendencies.
Chapter
With increasing oil and gas exploration and production operations shift towards offshore, challenges imposed by the subsea environment on material integrity and stability also increase. In hostile subsea environment, material corrosion is often difficult to evaluate but significantly influences the safety, longevity and cost of any oil and gas project. It is of great importance to understand fundamental corrosion mechanisms as the unique subsea environment impact on oil and gas facilities. Such development also provides great opportunities for academia and industry collaboration to tackle both the scientific and technological important questions in materials science, physical chemistry, manufacturing, and instrumentation as an integrated part of the engineering problem.
Article
Purpose In spite of the high interest in thermally sprayed aluminium (TSA) to protect offshore structures, pipelines, risers, etc., data correlating the exposure of TSA-coated steel in hot seawater to its performance are lacking. No information is available on the performance of TSA in hot seawater, especially when damaged. This paper aims to address this knowledge gap and report the corrosion performance of damaged TSA on carbon steel exposed to boiling synthetic seawater for different periods (up to 5,000 h). It also attempts to understand the mechanism of formation of calcareous deposits in boiling synthetic seawater by using various characterisation tools. Design/methodology/approach Twin wire arc spray was used to coat carbon steel specimens with commercially pure aluminium. Holiday was drilled on the coated surface to expose the underlying steel, amounting to 4 per cent of the specimen surface area. These specimens were then exposed to boiling synthetic seawater for different periods: 2, 68, 188, 335 and 5,000 h. During exposure, the potential was monitored (vs standard calomel electrode [SCE]) and linear polarisation resistance (LPR) method was used to calculate the corrosion rate (CR). After exposure, these specimens were analysed by using characterisation tools such as X-ray diffraction (XRD) and scanning electron microscope (SEM)/energy-dispersive X-ray spectroscopy (EDX). Findings The TSA-coated steel samples with 4 per cent holiday showed a CR of approximately 0.008-0.015 mm y ⁻¹ and a stable potential (E corr ) around −800 mV (SCE), when exposed to boiling synthetic seawater for approximately 5,000 h. Microstructural characterisation established that the deposits comprised brucite [Mg(OH) 2 ] only (this is very different to what has been reported at ambient temperatures). The stable potentials obtained after 5,000 h suggest that the brucite layers provided effective corrosion mitigation. Thus, TSA seems to show the potential to protection hot carbon steel risers, even when damage exposing the external steel surface to the seawater is present. Originality/value The mechanism of calcareous deposit formation has been studied for many years, but most of the previously reported studies concentrate on low or ambient temperature behaviour. The reported studies mainly concentrate on the application of cathodic protection, rather than the effect of TSA. This is the first journal paper where the behaviour of damaged TSA in boiling synthetic seawater has been reported. The formation of brucite-only layer in the damaged area adjacent to the steel surface in boiling synthetic seawater is novel. And the mechanism of formation of this layer has been explained in the paper.
The main purpose of this research was to establish the effectiveness of the V844 corrosion inhibitor for seawater on various metallic materials: carbon steel, aluminum and copper alloy at different concentrations via colloid formation. The changes in both physical and chemical properties of seawater, including pH, total hardness, alkalinity, total dissolved solids (TDS) and conductivity at different concentrations of V844 were assessed, too. The test procedure involves dissolving the V844 corrosion inhibitor powder provided by Magna International Private Limited in seawater to obtain a stock solution of 4% V844 in seawater, which was further diluted to obtain the remaining concentrations. The analysis of parameters begun when various metal species, polished beforehand, were placed into the solutions. The analysis was observed over a period of 26 days and a total of 9 sets of readings were obtained. From our observation and analysis, it was concluded that the inhibitor worked best at 0.05% concentration for carbon steel.
Article
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Most metals exist in nature as stable ores of oxides, carbonates or sulfides. Refining them, to make them useful, requires energy. Corrosion is simply nature's way of reversing an unnatural process back to a lower energy state. Preventing corrosion is vital in every step in the production of oil and gas.
Article
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Corrosion in oil/water systems in the oil industry continues to be a major problem that has not been adequately addressed. This article describes, in a qualitative manner, the mechanisms involved in three well-defined regions of behavior with an emphasis on region 1, which is the most important in predicting the onset of corrosion for these mixtures.
Chapter
Stress-corrosion cracking; Austenitic stainless steels; Heat treatment; Chemically stabilized steel; Molybdenum
Book
Standard Handbook of Petroleum and Natural Gas Engineering, Third Edition, provides you with the best, state-of-the-art coverage for every aspect of petroleum and natural gas engineering. With thousands of illustrations and 1,600 information-packed pages, this handbook is a handy and valuable reference. Written by dozens of leading industry experts and academics, the book provides the best, most comprehensive source of petroleum engineering information available. Now in an easy-to-use single volume format, this classic is one of the true "must haves" in any petroleum or natural gas engineer's library. A classic for over 65 years, this book is the most comprehensive source for the newest developments, advances, and procedures in the oil and gas industry. New to this edition are materials covering everything from drilling and production to the economics of the oil patch. Updated sections include: underbalanced drilling; integrated reservoir management; and environmental health and safety. The sections on natural gas have been updated with new sections on natural gas liquefaction processing, natural gas distribution, and transport. Additionally there are updated and new sections on offshore equipment and operations, subsea connection systems, production control systems, and subsea control systems. Standard Handbook of Petroleum and Natural Gas Engineering, Third Edition, is a one-stop training tool for any new petroleum engineer or veteran looking for a daily practical reference. Presents new and updated sections in drilling and production Covers all calculations, tables, and equations for every day petroleum engineers Features new sections on today's unconventional resources and reservoirs.
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Galvanic interactions between steel and liquid mercury were examined in aqueous environments that simulate waters found in pipelines used in oil and natural gas transportation. Liquid elemental mercury is a poor cathode for hydrogen ion reduction and thus provides little galvanic influence to corrosion of steel in anaerobic aqueous systems containing either hydrogen sulphide or carbon dioxide. The measurements confirm industry experience that liquid mercury on steel in pipelines poses little risk to accelerate corrosion reactions and thus to compromise structural integrity, at least as far as galvanic corrosion is concerned. The measurements extend the conventional view of elemental mercury as a metal with low electrocatalytic efficiency for hydrogen ion reduction to environments containing mostly HS- and HCO3-.
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Monel Ni-Cu-Al Alloy K-500 bolts failed by cracking after short periods of service as subsea riser clamp bolts on Occidental Petroleum Caledonia, Ltd. 's Pipe Alpha platform in the UK North Sea. All of the bolt failures occurred in the most highly stressed clamps for each riser. The failure mechanism was hydrogen embrittlement caused by a specific set of material and environmental conditions. Severely cold worked material from the thread machining operation, followed by the precipitation hardening heat treatment resulted in localized areas of high hardness (above HRC 35) in the thread root. This, coupled with the high stress level on the bolts in these clamps and cathodic polarization from the platform cathodic potection system, resulted in hydrogen charging of the thread root followed by failure from hydrogen embrittlement. As a result of this experience, a specification for Monel Alloy K-500 bolts has been implemented that has prevented a recurrence of this type of failure.
Article
A conscientious pipeline operator must monitor many aspects of possible operational pipeline deterioration. Some operators must deal with manufacturing defects known as 'hard spots.' Under certain conditions, hard spots may crack and fail. Cathodic protection may be a contributing factor in a failure. A magnetic flux leakage tool readily detects regions of elevated hardness (hard spots) in line pipe.
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The use of 100-mV polarization criterion was thought to be an approach to maximize pipeline operational compliance with the integrity management programs in the Gulf and northern regions of Mexico during the pipeline survey. The needs of investments in refurbishing the CP infrastructure can be reduced by integrating the 100-mV cathodic protection (CP) criterion and its procedures into the algorithms of integrity management and regular CP surveys. Leaks related to pipeline failures caused over 500 incidents in Southeast Mexico. The survey covered 5,000 km of ROWs distributed in areas in the Gulf and northern regions of Mexico with very different landscapes and weather conditions. The use of the 100-mV criterion may also help in solving the problem of complying with pipeline integrity management programs.
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Mixed metal oxide (MMO) coated titanium anodes exhibit excellent performance characteristics in most cathodic protection (CP) applications. MMO coated titanium anodes have ability to be operated at high current densities (CD) for initial structure polarization, resistance to low pH, and ability to operate in fresh water, soil, seawater, and concrete electrolytes with or without backfill. Three typical applications include tubular electrodes in deep anode configurations for pipelines and well casings, ribbon for CP of aboveground storage tank bottoms, and expanded titanium ribbon mesh for protecting reinforcing steel in concrete. The anode is supplied with the optimum MMO coating for the application to ensure performance that satisfies CP system design criteria. Expanded mesh and ribbon mesh MMO anodes demonstrate superior performance for CP of reinforcing steel in concrete structures.
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The impact of low-quality magnesium anodes marketed in the US, in terms of lower current efficiency and a subsequent anode life, is discussed. Testing of open-circuit potential (OCP) and current efficiency is performed in accordance with ASTM Standard Test Method, involving destructive testing of anode samples over a 14-day period. A simplified value analysis for each of the test anodes shows an impact of current efficiency on the overall annual cost of the anode. Using the mean value of 38% current efficiency derived from test data, the estimated annual cost to inventory exceeds $2 million USD. The study has also indicated that a company purchasing 10,000 anodes a year would experience more than $50,000 annually of additional cost as a result of low-quality magnesium. It is recommended that the end-users need to routinely test anodes to ensure that current efficiency specifications are being met.
Article
Many of the anodes marketed in the U.S. today do not meet minimum quality requirements. This article discusses the transition of magnesium anode sources from U.S. to foreign manufacturers and points out the effects of not meeting the various quality requirements. Anode specifications should include quality standards for open-circuit potential and current efficiency as well as alloy chemistry. Operating costs for nonquality anodes exceed costs for anodes meeting quality standards, suggesting that purchasers should place more emphasis on quality and less on initial cost.
Article
Solitary and binary inhibition effects of ammonium (NH4NO 3) + A length of S135 drill pipe that broke during pumping from a well that contained hydrogen sulfide was investigated. The drill pipe broke at 950 mm from the box end. There was no obvious plastic deformation at the fracture. Radial lines on the outside surface of the pipe were located on the flat fracture and accounted for 1 2.5% of the whole fracture. Another fracture showed tilted morphology with different orientations. Scanning electron microscopy (SEM) with an energy dispersive analyzer (EDA) showed that the micro-fracture morphology was intergranular and sulfur was identified at the fracture. The microstructure of the drill pipe was tempered Sorbite. Test results led to the conclusion that the macro and micro-fractures and failure were caused by sulfide stress cracking (SSC). The possibility that fracture was due to material defects can be excluded because the composition, microstructure, and mechanical properties of the drill pipe are in accordance with the API Specification 5D standard.
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This manual is a collection of information on practices, techniques, materials and equipment, and related material on basic corrosion, cathodic protection theory, measurement practices, construction details and typical methods of installation and operation tested in field applications. (P.J.B.)
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Liquid pipeline service failures have occurred because of pressure-induced fatigue crack growth. Crack growth models can be used to evaluate the effects of pressure-cycle-induced growth on the possibly remaining flows in a pipeline. The use of one such model, RETES, is described. RETEST was used to determine years to failure for six locations on a pipeline. A safety factor of two was recommended.
Article
Whether its called fixed equipment (at ExxonMobil), stationary equipment (at Shell), or static equipment (in Europe), this type of equipment is the bread and butter of any process plant. Used in the petrochemical industry, pharmaceutical industry, food processing industry, paper industry, and the manufacturing process industries, stationary equipment must be kept operational and reliable for companies to maintain production and for employees to be safe from accidents. This series, the most comprehensive of its kind, uses real-life examples and time-tested rules of thumb to guide the mechanical engineer through issues of reliability and fitness-for-service.This volume on piping and pipeline assessment is the only handbook that the mechanical or pipeline engineer needs to assess pipes and pipelines for reliability and fitness-for-service.
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The effects of dissolved hydrogen in the failure of plain and low-alloy steels has been studied extensively. Hydrogen embrittlement (HE), in the manifestation of sulfide stress cracking, is a continuing concern in the oil, gas, and petroleum industries, despite years of research into cracking mechanisms, parameters, and control methods. Also well documented is HE cracking of electroplated fasteners. Less appreciated is the long-term effect of hydrogen on cracking of high-strength sleels and ferrous alloys under atmospheric exposure conditions. This article discusses failures of high-strength fasteners caused by HE in atmospheric environments and the danger this cracking presents. Recommendations an provided for reducing fastener failures by HE.
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The instant off technique for the determination of the value of the potential to which a metal has been polarised by the action of a cathodic protection current implicitly relies on the time scales of the various polarisation decay processes being very different. Normally measurements are taken between 0.1 and 1 second after the interruption of the current and the assumption is made that in this time the activation and diffusion polarisations have not decayed by a significant amount. This paper attempts to calculate the time constants for the decay associated with the ohmic, activation, and diffusion components of the polarisation. It suggests that there may be such an overlap between the different decay processes that differentiation between them is not possible. The calculations when applied to steel in sea-water and reinforcing bars in concrete suggest that such is the difference between these typical systems that generalised criteria are not possible.
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S-N fatigue tests were carried out on weldments of 9% nickel steel, which is often used in cryogenic applications. The objective was to confirm that the fatigue behavior at cryogenic temperature was at least as good as that at room temperature. The cruciform specimens were similar in configuration to those used to develop the F-curve, which is found in UK practice and generally recognized by other structural design standards worldwide. The specimens were left as-welded. Three tests were conducted at both room and cryogenic temperature and at two different stress range levels. Comparison of the results showed that the cryogenic condition improved the life noticeably at both stress range levels. This finding was not unexpected based on literature evidence as to the reduction in crack growth rate at lower temperatures for this particular material. Prior work demonstrated that 9% nickel weldments can be safely analyzed by the usual S-N curves for carbon steel weldments when at room temperature. Hence, this latest finding means the same conclusion applies to 9% nickel weldments at cryogenic temperatures. Copyright © 2008 by The International Society of Offshore and Polar Engineers (ISOPE).
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Crevice corrosion of corrosion-resistant alloys (CRAs) was studied. The crevice pH effect on initiation was investigated with the results of the linear relation between electric charge and crevice pH. The crevice pH decreased easily compared with the behavior obtained in seawater environments. Passive current density was obtained by subtracting the H 2S oxidation current density measured on the Pt electrode from that on alloys and agreed well with the current density obtained by solution analysis. The relationship between the electric current passing through the alloy and crevice pH with passive current density was used to calculate the incubation time for crevice initiation based on the model proposed for a sea water environment. The incubation time increased proportionately with the alloy element concentration. The critical condition of crevice initiation is discussed with the Pourbaix diagram for sour gas environments with depassivation pH of alloy. It is concluded that corrosion-resistant alloys hardly suffer from crevice corrosion as far as pH of environments is determined by dissolved gas. The application limit of CRAs predicted from the initiation of crevice corrosion involves the pitting corrosion occurrence. The application limit determined by the initiation of pitting corrosion yields the most reliable criterion for material selection.
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Microbiologically influenced corrosion (MIC) can be misdiagnosed as attack caused by conventional chloride crevice/pitting corrosion unless specialized techniques are used during the failure analysis. These techniques include in situ bacterial sampling of residual water, bacterial analysis of corrosion products using analytical chemistry, culture growth, and scanning electron microscopy as well as nondestructive examination using ultrasonics and radiographic techniques. Metallographic examination can reveal MIC characteristics such as dendritic corrosion attack in weld metal. Three case histories involving AISI 304 and 304L stainless steels are presented to illustrate the failure analyses.
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This paper shows the effects of cathodic protection in crevices in mild steel in sea water, saline water, and brackish water. Test conditions simulated a crevice under a disbonded pipeline coating. Results indicate the degree of cathodic protection with different surface treatments.
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A simplified model is proposed for predicting the critical velocity required to sweep out settled water in oil pipelines. On the basis of the mathematical analysis and laboratory experiments, it is found that the critical flow velocity for water entrainment is not related to any simple flow parameter such as the Reynolds number. Qualitatively, oil flowing over water which has settled out on the bottom of a horizontal pipeline will cause water waves to form if the oil velocity is great enough. At still higher velocities, the waves become unstable and water droplets will be torn from the crests of the waves. If the oil velocity is sufficiently high, the water droplets will be entrained in the flowing stream and eventually all of the water will be swept away. The factors which govern the formation of water droplets and their sizes are found to be: (1) the oil and water specific gravities, (2) the interfacial tension between the oil and water, (3) the viscosity of the oil, (4) the pipe diameter, and (5) the velocity.
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A corrosion management program undertaken by a team of engineers to inspect corrosion of a pipeline on the western side of BP Exploration Inc. (BPXA's) Prudhoe Bay field in Alaska that occurred on March 2006, is discussed. The team faced a host of internal and external corrosion concerns that were managed by the use of several mitigation programs and ongoing risk-based inspections. The chemical corrosion inhibitors are continuously injected at the wellheads and carried through the system by the use of 2 million gallons per year. Inhibitors create a single molecular layer called adsorption that provides a protective barrier from corrosive fluids and gets repaired by itself. Ultrasonic radiographic testing methods were conducted for investigating inline inspection commonly referred to as smart pigging for pipelines above the ground. However, BPXA concluded that the level of corrosion was within the industry and pipeline replacement will ensure the integrity of BPXA's systems in future.
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Corrosion under insulation is a major problem in a variety of industries. Whether the pipe or other structure is buried or above ground, using proper design and installation techniques can control corrosion. There are several very good articles on the correct way to install insulation and the problems incurred by the loss of insulating properties when the insulation becomes saturated with moisture. Insulation normally becomes wet due to poor installation practices or failure to install sufficient vapor barrier and waterproofing materials. Moisture in insulation increases heat loss and deteriorates the insulation. i This article will mainly discuss the proper selection, installation and use of coatings on the metal before the insulation is applied. My corrosion control experience has been in the oil and gas pipeline industry, but my experience involves corrosion control in other industries. The corrosion process of metals is basically the same in all industries, yet, there are definite differences in the methods of corrosion control facing the "cold piping" industry. Many of the methods used in the pipeline industry can be used for controlling corrosion under insulation on either hot or cold pipes; we will deal primarily with cold systems.
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Carbon steel coiled-tubing (CT) strings have been used in sour wellbore environments for many years. The use of CT in sour service has increased by job number, job complexity, pipe size, and the stresses to which the pipe is subjected. A number of papers have been written on the steel chemistry and low-cycle fatigue behavior. These papers have been based on both theoretical and laboratory work. Great progress has been made in understanding the chemical and physical interaction of CT and H2S, but little information is available from "real-world" situations in which the pipe has been worked in a variety of job types (e.g., acidizing, gas lifting, and drilling) and in which a large number of other factors may come into play (e.g., injector damage, well-stimulation chemicals, sour inhibitor application techniques, erosion of inhibitors, CO2, and high-chloride water production). This paper discusses the application of a CT technical specification (based on theoretical and laboratory work) in the operational world. Comparisons will be made between theoretical expectation and practical observation for 70- and 80-grade CTs with regard to low-cycle fatigue, pipe life, and damage in sour environments.
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An evolution has occurred with low-alloy steels and corrosion-resistant alloys to address corrosive oil and gas production needs. This evolution occurred because of the extensive laboratory and on-site testing and the significant potential for economic and fitness-for-purpose gains. These alloys have evolved with primarily higher yield strengths than those used in the petrochemical industry. For many metals, a strength restriction arises if hydrogen sufide (H2S) is present. The current uses of these alloys have resulted in pushing the limits of the use of low-alloy steels and the less heavily alloyed corrosion-resistant alloys. This paper addresses the many modes of environmentally assisted cracking that have been identified while evaluating strength limitations of low-alloys steels and corrosion-resistant alloys with the intention of capturing the significant ideas and unresolved question within the alloy development and testing framework.
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Components made from cast nickel aluminum bronze have been used extensively in some seawater systems because of their generally good toughness. However, this alloy can be susceptible to selective phase corrosion. This has led to requirements for removal of components on a fixed timetable to test for the presence of this corrosion. Significant savings in cost and labor could be achieved if components were only removed when significant corrosion damage had actually occurred. In an effort to find a useful method for online corrosion monitoring, several electrochemical techniques were assessed to determine if they could detect the onset of selective phase corrosion in specimens exposed to clean, flowing seawater that was subject to occasional injections of sulfides liberated from decaying marine organisms. Prior to immersion in the seawater, individual specimens were subjected to different heat treatments intended to either enhance or reduce susceptibility to selective phase corrosion. At the conclusion of the electrochemical tests, specimens were sectioned and inspected for evidence of selective attack.
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Effect of heat treatments and resulting changes in microstructure on general and localized corrosion susceptibility of lean duplex stainless steel UNS S32101 in caustic and chloride solutions was investigated. Results show that changes in the microstructure (ferrite phase/austenite phase ratio and intermetallic precipitation) of the duplex stainless steel (DSS), due to different annealing and aging treatments, affect its general and pitting corrosion resistance. The role of DSS microstructure in localized corrosion susceptibility was found to be significantly different in the chloride environments as compared to caustic environments.
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A new testing facility for a high-velocity, three-phase flow consisting of a gas flow loop and a jet impingement rig is described. Flow velocities between the nozzle and specimen have been determined through computational fluid dynamics (CFD) simulations and by particle image velocimetry. Tests were conducted on typical carbon steels (J55 and C95) that are used in tubings for the gas and oil industry. Flow conditions of a sweet gas condensate well have been applied. Mass-loss rates have been determined after testing times of between 4 h and 168 h using optical profilometry. Damaged surfaces were investigated using optical and scanning electron microscopy. The effects of material and flow velocity on the mass-loss rate have been investigated. Mass loss of specimens under given conditions is determined by siderite formation and increasing degradation of siderite layer by impacts of sand and fluld droplets. Degradation happens by erosion-enhanced corrosion. Normalized steel J55 behaves like a ductile material resulting in a maximum degradation rate under small impact angles outside the focal spot. Compared to J55 the quenched and tempered material C95 shows a generally lower depth of attack with its maximum degradation under large impact angles, indicating a brittle behavior. Cementite of pearlite may act additionally as a cathode and accelerate corrosive attack.