Gas Production Environments Research Articles

Alumina-based ceramic coatings obtained by the SHS process for high temperature corrosion and wear protection of steel tubulars

Ceramic coatings have much potential for steel tubulars' protection against high temperature corrosion of gases and liquids, often containing abrasive solid particles, and to enhance their integrity in severe power generation, mineral and oil & gas production environments. Combining self-propagating high-temperature synthesis (SHS) with high-speed centrifugal process, alumina-based coatings were produced onto the inner surface of tubulars for these applications. According to the developed SHS batch formulation and the designed centrifugal device and process, well-consolidated composite ceramic layers with a thickness of 1.5–3 mm have been obtained. The developed SHS process does not create hazardous gases, and it takes ∼30 s for the ceramic phase formation. A high-level compaction due to centrifugal forces and a liquid phase sintering approach provided a dense gradient ceramic structure formed by oxide grains cemented by a glassy phase and bonded with a steel substrate through a thin iron layer. The coatings were successfully produced onto the inner surface of carbon and stainless steels’ tubes of up to 12 ft-lengths and standard dimensions from 2 to 3/8″ to 7.5” OD. The coatings were tested, for the first time, in wear and high-temperature corrosive environments, e.g., in steam–H2S–CO2 gases and molten salts, with encouraging results due to high contents of Al2O3 and some other oxides and consolidated ceramic structure. They can be recommended for applications in high-temperature (900 °C and greater) corrosive environments and erosive flows.

Under-deposit microbial corrosion of X65 pipeline steel in the simulated shale gas production environment

The synergistic effect of sand deposit and sulfate-reducing bacteria on the X65 pipeline steel was investigated in the simulated shale gas production environment, by means of weight loss tests, EIS, SEM and EDS. The results indicated that the coexistence of sand deposit and sulfate reducing bacteria (SRB) resulted in 63% reduction in uniform corrosion, but 183% increase in localized corrosion rate. The EIS results revealed that the formation of biofilm altered the protectiveness of the surface mixed layer and showed a trend related to the bacterial growth curve. The mixed layer was also clarified from the cross-section morphology and EDS analysis. This mixed layer may hinder the diffusion of substances to the deposit/steel interface, thus creating a microenvironment at the deposit/steel interface that promotes localized corrosion.

Effect of hydrogen sulfide and chloride on the passive film structures of stainless‐steel type 316 L

AbstractThe presence of hydrogen sulfide and chloride in oil and gas production environments can induce deterioration of the passive film, leading to pitting corrosion of stainless steel. In this research, localized behavior of stainless‐steel type 316 L was studied in highly hydrogen sulfide and chloride environment. The environmental condition was setting up using NACE TM0177 Solution A at different partial pressures of 0 bar, 3 bar and 15 bar of hydrogen sulfide, respectively. The results indicated that the presence of sulfides and chloride ions in test solution can decrease its corrosion resistance due to pitting corrosion attacking and promoting passive layer break down. Deterioration of passive film was analyzed using weight loss calculation, pit penetration analyses was done by infinite focus microscopy and surface morphology with the corrosion products were investigated by scanning electron microscope after 7 days immersion in test solution. Energy‐dispersive x‐ray results shows the presence of sulfur on the passive oxide layer at 3 bar and 15 bar conditions. Thus, the protection for these steels is undermined by hydrogen sulfide corrosion that affects on the passive films and altered its structure.

SMOOTH AND REDUCED OIL AND GAS PIPES WITH INCREASED CORROSION RESISTANCE

Formulation of the problem. Corrosion of pipes used in the oil and gas industry leads to significant economic losses, therefore, increasing their corrosion resistance and durability is an urgent task. Purpose: generalization of results of developments of technologies of manufacturing and research of qualitative characteristics of oil and gas pipelines (smooth) and pump-compressor (threaded) pipes of the increased and high corrosion resistance and giving recommendations on their application in oil and gas industry in environments of various corrosion aggressiveness. Methodology. The microstructure of tubular steels and protective coatings was studied by light metallography and electron microscopy. Complex corrosion studies included laboratory tests of samples in model chloride and hydrogen sulfide-containing media, the resistance to sulfide corrosion cracking under stress (SCCS) and hydrogen cracking (НС) according to the methods of NACE TM 0177 and NACE TM 0284 as well as operational tests at the oil fields of Ukraine. Mechanical properties for stretching and impact bending of samples by standard methods. Results. The results of the development of production technologies and the study of the qualitative characteristics of oil and gas pipelines and tubing with increased and high corrosion resistance in aggressive oil and gas production environments are summarized. The influence of the chemical composition of steels and protective coatings, as well as pipe manufacturing technologies on their microstructure, corrosion resistance in various media, and mechanical properties is shown. Scientific novelty. For the first time, the presence of special low-energy boundaries in the ferrite of low-alloy ferrite-pearlite and high-alloy ferritic-austenitic steels was established, their number and energy level were estimated. The high operational reliability of threaded pipes with a protective coating is substantiated. Practical value. The results of the work and recommendations for the rational use of oil and gas pipes with increased corrosion resistance can be used to increase the economic efficiency of production in the oil and gas industry.

Environmentally Assisted Cracking of Subsea Pipelines in Oil & Gas Production Environments—Effect of Static Loading

Fatigue crack growth rate of line pipe steels in sour environments typically exhibits a steady-state value at low frequencies. However, in highly inhibited sour environments, there is no evidence of a steady-state fatigue crack growth at low frequencies. This is likely a result of static crack growth rate at Kmax. Stable static crack growth measured under constant stress intensity factor (K) conditions in inhibited sour environments was in the range of 10−7 mm/s to 10−8 mm/s. The crack growth rate in inhibited sour environments is likely associated with crack tip processes associated with metal dissolution/film formation and associated hydrogen evolution. The results obtained were modeled based on a crack tip strain rate based approach, where the rate limiting step was the metal dissolution/FeS formation and the corresponding hydrogen generation reaction.

The edge architecture for semi-autonomous industrial robotic inspection systems

Robots have been increasingly used in industrial applications, being deployed along other robots and human supervisors in the automation of complex tasks such as the inspection, monitoring and maintenance of industrial assets. In this paper, we shared our experience and presented our implemented software framework for such edge computing for semi-autonomous robotics inspection. These systems combine human-in-the-loop, semi-autonomous robots, edge computing and cloud services to achieve the automation of complex industrial tasks. This paper describes a robotic platform developed, discussing the key architectural aspects of a semi-autonomous robotics system employed in two industrial inspection case studies: remote methane detection in oilfields, and flare stack inspections in oil and gas production environment. We outline the requirements for the system, sharing the experience of our design and implementation trade-offs. In particular, the synergy among the semi-autonomous robots, human supervisors, model-based edge controls, and the cloud services is designed to achieve the responsive onsite monitoring and to cope with the limited connectivity, bandwidth and processing constraints in typical industrial setting.

The edge architecture for semi-autonomous industrial robotic inspection systems

Robots have been increasingly used in industrial applications, being deployed along other robots and human supervisors in the automation of complex tasks such as the inspection, monitoring and maintenance of industrial assets. In this paper, we shared our experience and presented our implemented software framework for such edge computing for semi-autonomous robotics inspection. These systems combine human-in-the-loop, semi-autonomous robots, edge computing and cloud services to achieve the automation of complex industrial tasks. This paper describes a robotic platform developed, discussing the key architectural aspects of a semi-autonomous robotics system employed in two industrial inspection case studies: remote methane detection in oilfields, and flare stack inspections in oil and gas production environment. We outline the requirements for the system, sharing the experience of our design and implementation trade-offs. In particular, the synergy among the semi-autonomous robots, human supervisors, model-based edge controls, and the cloud services is designed to achieve the responsive onsite monitoring and to cope with the limited connectivity, bandwidth and processing constraints in typical industrial setting.

Corrosion behavior of epoxy composite coatings reinforced with reduced graphene oxide nanosheets in the high salinity environments

Epoxy composite coatings reinforced with different contents of reduced graphene oxide (RGO) nanosheets were prepared on N80 substrate. The aim of this work is to identify the applicability of RGO modified epoxy coatings on N80 tubing in oil and gas production environments with high temperature and high salinity. Transmission electron microscopy, selected area electron diffraction and scanning electron microscopy were employed to characterize the RGO and coatings. The adhesion, toughness and corrosion resistance of epoxy composite coatings were investigated. It indicated that the proper addition of RGO nanosheets effectively reduced the number and size of pores in the epoxy composite coatings, and improved the adhesion, toughness, corrosion resistance of the epoxy composite coatings. The epoxy composite coating with 1.0 wt% RGO displayed the best anti-corrosion performance in 10.0 wt% NaCl solution.

A method of moments approach to model the electromagnetic response of multiple steel casings in a layered earth

In oil and gas production environments, controlled-source electromagnetics can be used to aid brownfield exploration, development, and reservoir monitoring efforts. However, such environments typically have many highly conductive steel-cased wells in the area of interest. We have developed a modeling algorithm using a method of moments (MoM) approach to calculate the electromagnetic response of multiple 3D steel-cased wells of arbitrary geometry in a layered earth conductivity model. This approach involves dividing each casing into a collection of segments, each carrying a uniform current density. A matrix is computed that describes how the casing segments interact with each other electromagnetically. Then, we solve a linear system for the current within each casing segment, given a transmitter of arbitrary frequency and location. From these currents we are able to solve for the secondary electromagnetic fields produced solely by the casings at any point in our layered model, and we add these to the primary fields produced by the transmitter. To validate the algorithm, we compared results with a pseudoanalytic MoM algorithm for a single vertical casing in a half-space. We also compare results with a finite-element solution using Comsol Multiphysics for vertical and single tilted wells buried in various layered earth models. Our results indicate a good match between these different approaches, with tilted casings in a layered model requiring further study. Finally, we applied our algorithm to a realistic synthetic model with three casings (one vertical and two deviated) extending into a layered earth model containing the classic thin resistive layer. This example illustrates how the algorithm can be used to compute the electromagnetic response of multiple steel casings. The example also illustrates how the electromagnetic field changes due to the presence of the casings and how the casings may be used to inject the signal at depth.

Corrosion-resistant alloy testing and selection for oil and gas production

ABSTRACTCorrosion-resistant alloys (CRAs) are employed in severe oil and gas production environments that operate at high pressures and temperatures and contain chlorides, CO2, and H2S. They exhibit high resistance to uniform corrosion in these environments due to their passivity. However, they can suffer from different forms of environmentally assisted cracking (EAC), depending on the environmental and metallurgical conditions. This paper reviews the recent literature of EAC in CRAs and presents an overall framework for evaluating the SCC based on electrochemical modelling of corrosion and repassivation potentials for localised corrosion. The modelling is supported by experimental data on crack growth as a function of environmental variables, alloy content, and potential.This paper is part of a supplementary issue from the 17th Asia-Pacific Corrosion Control Conference (APCCC-17).

Effect of K-rate and cathodic protection potential on fracture toughness of the super duplex stainless steel UNS S32750

Super duplex stainless steels (SDSS) have emerged in the last decade or so asa candidate material to withstand harsh oil and gas production environments. However, documented cases of failure due to hydrogen induced stress cracking (HISC) have raised some concerns. The aim of this investigation is to evaluate the effect of the cathodic protection potential and K-rate on the susceptibility of SDSS to HISC. The results indicated that although the susceptibility to HISC might appear unequivocal, the tests parameters should be carefully considered since they influence dramatically on the results produced. Indeed, for more cathodic electrode potentials stronger is the detrimental effect on fracture toughness while the influence of K-rate is rather weak. However, the influence of this latter parameter becomes more relevant when the applied electrode potential is less negative.

ANALISIS KERUSAKAN SAMBUNGAN LASAN PADA SISTEM VENTING PRE AIR COOLER DI LINGKUNGAN EKSPLORASI DAN PRODUKSI GAS ALAM

The purpose of this study was to determine the cause of damage to the welded joints in the spool pipe on the pre-cooler air venting system in the natural gas exploration and production environment in the form of crack defects. The analysis was done by taking field data in the form of operational data and chemical content of fluid served, visual observation, chemical composition test with Optical Emission Spectrocopy, Hardness Testing using Rockwell scale B, Micro observation and makrophotograpy, Metalographic observation, microhardness testing using Vickers test plane, Observation of macro fracture surface using Scanning Electron Microscope. Based on the results of the tests and observations, it shows that the main cause of the damage is the brittle crack caused by the welding performance made possible by the use of higher current than required and rapid cooling of the welding of the thin material.

Modeling Localized Corrosion of Corrosion-Resistant Alloys in Oil and Gas Production Environments: Part II. Corrosion Potential

A recently developed framework for predicting localized corrosion and stress corrosion cracking of corrosion-resistant alloys (CRAs) in oil and gas production environments relies on the computation...

Localized Corrosion of Corrosion Resistant Alloys in H2S-Containing Environments

Corrosion resistant alloys (CRAs) are widely used in harsh oil and gas production environments where low-alloy steels cannot be used. It is recognized that stress corrosion cracking (SCC) of stainless steels and Ni-based alloys can occur at potentials above the repassivation potential (Erp) for localized corrosion. This paper focuses on experimental work that has been conducted to determine Erp of six CRAs, i.e., super-martensitic stainless steels S13Cr (UNS S41425) and S15Cr (UNS S42625), super-duplex stainless steel 2507 (UNS S32750), and solid solution Ni-based Alloys 2535 (UNS N08535), 29 (UNS N08029), and 28 (UNS N08028) in chloride-H2S environments. A generalized approach is applied to determine Erp values from electrochemical polarization results at temperatures ranging from 85°C to 232°C. The use of completely deaerated solutions and ensuring the stable growth of localized corrosion are both critical to obtain conservative Erp values for CRAs in environments that are similar to downhole conditions...

Effect of short-term infusion of hydrogen on enteric gas production and rumen environment in dairy cows

Methane (CH4) production by rumen methanogens lowers hydrogen (H2) pressure and, in theory, prevents inhibition of fermentation processes by H2 accumulation. The present study aimed at examining effects of short-term H2 infusion on CH4 production and the volatile fatty acid (VFA) profile. Four lactating Holstein dairy cows fitted with rumen cannula were each infused once with pure H2 into the rumen at a rate of 48.0 L/h during 5.75 h in between the morning and afternoon feeding. Gas exchange and feed intake were measured continuously by open-circuit respiration chambers during 5 days. Rumen liquid was sampled twice a day in connection with milking and feeding (0630 hours and 1700 hours) and analysed for VFA. Gas exchange and dry matter intake (DMI) were analysed for 5-h steady-state H2 concentrations (TI5) measured in respiration chambers and for 24-h time intervals (TI24) on the day before, during and after infusion. Hydrogen infusion did not affect the total VFA concentration and VFA molar proportions for either time interval. Methane production was higher for TI5 during infusion (130 L/5 h) than it was the day before infusion (120 L/5 h), but not the day after infusion (122 L/5 h). Methane production for TI24 and DMI for TI5 and TI24 were unaffected. Oxygen consumption and CH4 : CO2 were highest during infusion for TI5, but not for TI24. After correcting for H2 naturally produced, on average, 46.7 L H2/h was measured during TI5, indicating that 2.7% of the infused H2 was retained in the rumen. In conclusion, H2 infusion did not affect the VFA profile, but slightly increased CH4 production and CH4 : CO2.

油井環境における炭酸ガス腐食について

CO2圧入を行うCCSにおいては，CO2腐食に対する考慮が必要である．石油・天然ガスの採掘，生産環境においても，油井管やラインパイプにとって，貯留層に存在するCO2などの酸性ガスによる腐食作用が問題となる．本稿では，CO2環境での腐食現象の概要と，その対策について，既往の研究成果をレビューした．CO2腐食は，比較的高い腐食速度と，虫くい状腐食などの局部的な腐食形態となることが特徴である．また，CO2分圧や温度などの環境条件依存性が高いことや腐食に及ぼす流速の影響が極めて大きいことなども特徴として挙げられる．材料面からの対策としては，合金成分としてCrの添加が有効であることが知られており，CO2環境での防食対策としてスーパー13Cr鋼などのステンレス鋼製のOCTGやラインパイプが多く用いられてきた．

Modeling Localized Corrosion of Corrosion-Resistant Alloys in Oil and Gas Production Environments: Part I. Repassivation Potential

A model has been developed for predicting the localized corrosion repassivation potential (Erp) for alloys in environments containing chloride ions and hydrogen sulfide. The model has been combined with Erp measurements for a 13-Cr supermartensitic stainless steel (UNS S41425) at various concentrations of Cl− and H2S. The model accounts for competitive adsorption at the interface between the metal and the occluded site environment, the effect of adsorbed species on anodic dissolution, and the formation of solid phases in the process of repassivation. The effect of H2S is complex, as it may give rise to a strong enhancement of anodic dissolution in the occluded environment and may lead to the formation of solid metal sulfide phases, which compete with the formation of metal oxides. H2S can substantially reduce the repassivation potential, thus indicating a strongly enhanced tendency for localized corrosion and stress corrosion cracking. However, exceptions exist at lower H2S and Cl− concentrations, at whic...

Onshore Petroleum Centre of Excellence—collaboration by industry partners, government and TAFE to deliver trained staff for an expanding onshore petroleum industry

Santos, Beach Energy and Senex Energy are collaborating with the SA Government and TAFE SA to set up a hub for onshore oil and gas training in Adelaide. The training facility provides a fully immersive simulated oil and gas production environment, as well as static equipment displays for demonstration and educational purposes. It is used for technical training, including safety, environmental and sustainable operational principles and key maintenance activities. The simulated production environment includes different pump types, gas compressors, a pig launcher and receiver, gas metering skid, field separator and small tanks, as well as associated pressure safety valves, flow valves and other instruments. Water is used to simulate oil and air is used to simulate gas flow. The static equipment display includes various valve types, flanges and a wellhead. Santos, as operator of the SA Cooper Basin joint venture (of which Beach Energy is a member), has committed significant oil and gas production and mechanical equipment, engineering design, transportation and installation of the training facility’s equipment. The SA Government, Senex Energy and Beach Energy have committed funding for fit-out, capital works and the running of the facility for the first two years. Industry partners GPA Engineering, Fyfe Engineering, Logicamms, Veolia Environmental Services, Toll Energy, Transfield Services, Ottoway Engineering, Bureau Veritas, MRC Group, Max Cranes, Whitham Media Australia, Inductabend, Toyota Australia, James Walker Australia, Coventry Fasteners, Centralian Controls and Central Diesel are providing expertise and services. The training facility officially opened on 16 February 2015

The electrochemical behaviour of 316L austenitic stainless steel in Cl− containing environment under different H2S partial pressures

In oil–gas production environments, presence of H2S–Cl− can induce deterioration of the passive film, leading to pitting corrosion of stainless steels. In this paper, by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and capacitance measurements (Mott–Schottky analysis), the electrochemical behaviour of AISI 316L austenitic stainless steel was investigated in Cl− solutions under different H2S partial pressures (from 0 to 1.0bar). The results indicated that presence of H2S in Cl− solution can accelerate both the cathodic and anodic current density, leading to a metastable passive state in higher passive potential range, changing the semiconductor behaviour from p-type to n-type, increasing its susceptibility to corrosion. XPS analysis was employed to characterize the surface film after potentiostatic polarization, whose results provide good evidences for the electrochemical measurements.

Corrosion and stress corrosion cracking behavior of 316L austenitic stainless steel in high H2S–CO2–Cl− environment

In oil and gas production environments, H2S and Cl− can coordinate to cause pitting or stress corrosion cracking (SCC) of stainless steels. There has been limited work conducted on corrosion and SCC of autenitic stainless steels in high H2S–CO2–Cl− environments. In this paper, by four-point bending test method and scanning electron microscopy analysis, SCC of 316L steel was investigated under high H2S–CO2 pressures with 150,000 ppm Cl− at 60 °C. The effect of high H2S–CO2 pressure was discussed. The results indicated that the higher H2S–CO2 pressure can accelerate anodic dissolution process, deteriorate passive films, and aggravate SCC sensitivity. Using cyclic potentiodynamic polarization measurements, the corrosion behavior of 316L steel was studied in high H2S–CO2–Cl− environments. The effect of pH on pitting corrosion was discussed. Lower pH can promote both cathodic and anodic actions on 316L steel and facilitate passive film breakdown.