Sour Brine Research Articles

Surface analyses of corrosion products formed on API X-70 steel in sour brine after testing in a pipe loop

Flow assisted corrosion (FAC) is a problem of pipeline systems that handle high flow rates and strong direction changes. In the present investigation, FAC was tested on carbon steel exposed to the NACE 1D-196 environment by means an experimental pipe loop. As the exposure time increased, corrosion products formed a mixture of oxides, sulfides, and an apparent sulfate (rhombohedral mikasaite Fe2 (SO4)3), which was found in greater proportion and appeared to have a significant effect on decreasing corrosion rate. Transmission electron microscopy and x ray diffraction patterns seemed to confirm the presence of a sulfate and some oxides as the major chemical species contained in the corrosion products.

The quaternary ammonium salts as corrosion inhibitors for X65 carbon steel under sour environment in NACE 1D182 solution: Experimental and computational studies

The effect of quaternary ammonium salts (DDPC and DDQC) with different concentrations on the corrosion inhibition of X65 carbon steel in the sour brine solution at different temperatures were investigated by weight loss, electrochemical measurements, surface analysis (SKP, AFM, SEM, EDS, and ATR-FTIR), and theoretical calculations (DFT, Monte Carlo, and molecular dynamics). It was found that the corrosion rate decreased with increasing inhibitor concentration, and the inhibition efficiency was about 98%. The adsorption of inhibitors on the metal surface followed the Langmuir adsorption isotherm. Furthermore, inhibitors showed good performance at elevated temperatures. The computational studies supported the experimental data well.

Corrosion-Fatigue Crack Growth Performance of Titanium Grade 29 Welds in Tapered Stress Joints

Abstract Design of a steel catenary riser requires the use of connection hardware to decouple the large bending moments induced by the host floater at the hang-off location. Reliability of this connection hardware is essential, particularly in applications involving high pressure and high temperature fluids. One option for this connection hardware is the metallic tapered stress joint. Titanium (Ti) Grade 29 has been identified as an attractive material candidate for demanding stress joint applications due to its “high strength, low weight, superior fatigue performance and innate corrosion resistance”.2 Titanium stress joints for deepwater applications are typically not fabricated as a single piece due to titanium ingot volume limitations, thus making an intermediate girth weld necessary to satisfy length requirements. As with steel, the potential effect of hydrogen embrittlement induced by cathodic and galvanic potentials must be assessed to ensure long-term weld integrity. This paper describes testing from a joint industry project (JIP) conducted to qualify titanium stress joint (TSJ) welds for ultra-deepwater applications under harsh service and environmental conditions. Corrosion-fatigue crack growth rate (CFCGR) results for Ti Grade 29 flat welding-groove weld (1G/PA) gas tungsten arc welding (GTAW) specimens in seawater under cathodic potential and sour brine under galvanic potential are presented and compared to vendor recommended design curves.

The Corrosion of Cast Duplex Stainless Steels in Seawater and Sour Brines

Modern duplex stainless steels have been in use since the early 1970s and cast versions of the wrought alloys were soon in demand for pumps and valves. Since that time a range of cast duplex stainless steels have been developed with a wide range of compositions, but all with approximately 50/50 austenite/ferrite phase balance and deliberate additions of nitrogen. This paper presents some comparative corrosion data on a range of cast duplex stainless steels, mainly in seawater. The differences in performance related to composition and microstructure are discussed. Corrosion data in lower chloride brines are also presented to show the limits of use of some lower alloyed duplex materials. In addition to oxidizing chloride solutions, some data are presented on cast duplex stainless steels in reducing brines containing H2S, where the main corrosion problem is sulfide stress corrosion cracking. Finally, the importance of using a suitable technical specification, over and above ASTM, combined with selecting a suitably skilled foundry in order to obtain satisfactory castings is discussed.

The Effect of Jet Flow Impingement on the Corrosion Products Formed on a Pipeline Steel in Naturally Aerated Sour Brine

Corrosion was generated by the action of a jet impingement flow of sour brine on pipeline steel samples of X70. Flow-assisted corrosion affected nature, number and peak intensity of the chemical species formed as corrosion products. Iron sulfides predominated in static and low flow rate conditions (1.1 m/s), whereas at 2.4 m/s iron oxides were mainly formed, which led to higher corrosion rates and suggested that oxides are less protective than sulfides. On inhibition, imidazoline seems to mitigate oxide formation and support sulfide formation balancing both species on steel surface. Ferrite phase in laminar pearlite was preferentially dissolved with/without inhibitor, and mackinawite (FeS2) was formed at every flow rate, angle with and without inhibitor. Theoretical stresses determined by computational flow dynamics for corrosion product removal showed a fair approximation to those proposed in the literature.

Corrosion Inhibition of Pipeline Steel X-70 in Sour Brine by an Imidazoline Derivative under Flow Assisted Conditions

Corrosion Inhibition of Pipeline Steel X-70 in Sour Brine by an Imidazoline Derivative under Flow Assisted Conditions

Nitrogen and cod removal from tannery wastewater using biological and physicochemical treatments

An integrated wastewater treatment was evaluated for nitrogen and COD removal from a tannery effluent. The system was conformed by the combination of a biological treatment using a sequencing batch reactor (SBR) followed by a physicochemical treatment based in a coagulation-flocculation process. The contaminants in the tannery wastewater had average concentrations of 1546 mg COD·L−1, 200 mg TKN·L−1 and 121 mg N-NH4+ ·L−1. The duration of a complete SBR operation cycle was 12 h. Dissolved oxygen (DO), pH and oxidation–reduction potential (ORP) were used to monitor biological nutrient removal process in the reactor. In addition, densities of nitrifying and denitrifying microorganisms in the mixed liquor were evaluated during the biological treatment. During physicochemical treatment, the concentrations of FeCl3 .6H2 O and sour brine (agroindustrial waste used as adjuvant) were 2.7 and 100 g·L-1, respectively (doses were 60 and 5 mL·L-1, respectively). Results show the integrated treatment system was effective to produce an effluent suitable for discharge into water bodies, according to the Venezuelan environmental regulations. Average effluent concentrations were 303 mg COD L−1, 35.1 mg TN·L−1 and 0.5 mg N-NH4 + ·L-1, giving COD, TN and N-NH4 + removals of 80%, 82% and 99.6%, respectively. Profiles of ORP, DO and pH were efficient ways to monitor the evolution of biological nutrient removal and real-time control can be implemented in order to optimize the SBR operation. Finally, density of nitrifying bacteria was greater than density of denitrifying bacteria during biological treatment.

Technology Focus: Coiled Tubing Applications (June 2016)

Technology Focus Another tough year has passed since the last coiled-tubing feature in JPT. In spite of the difficult economic climate, the SPE/ ICoTA Coiled Tubing and Well Intervention Conference and Exhibition moved to a new venue this year, the George R. Brown Convention Center in Houston, because of the continued growth of the exhibition in prior years. Attendance was down by only a small percentage, which, I hope, is an encouraging sign. As mentioned in last year’s feature, the coiled-tubing industry is adapting to the changing environment. Several papers at this year’s conference discussed various aspects of subsea work performed with coiled tubing. Two papers presented different methods to use coiled tubing to enter or drill wellbores by using either an injector or a snubbing jack at the seabed and a secondary coiled-tubing injector at the surface. In both methods, the coiled tubing runs freely through the water— that is, the coiled tubing is not contained within a secondary riser pipe—and, hence, many in the industry are referring to this new technique as riserless coiled tubing. Other subsea operations mentioned included the use of coiled tubing as a downline for pumping fluids from a vessel to a subsea tree or pipeline. While this is not new to the coiled-tubing industry, tooling and vessel-based-equipment improvements have been developed to make operations safer and more versatile. Also in this arena, new thermoplastic composite materials are being introduced to the market and may bring further enhancements. These types of developments require considerable investment on behalf of the companies involved and tend to signal confidence in the longer-term return. Meanwhile, investment in furthering the understanding of the performance of steel materials for coiled-tubing well-intervention operations continues to grow. This performance envelope is being examined in terms of both the mechanical (e.g., abrasion and fatigue) and the environmental (e.g., sour-well environments). For example, renewed studies are being conducted on the combination of high-cycle elastic and low-cycle plastic fatigue, which currently has relevance to subsea work. Formerly, such studies were limited to the use of coiled tubing as a pump string. Additionally, established knowledge of solids transport in high-angle wells, from both field experience and laboratory work, is being applied more widely to reduce costs through increased efficiency. This has been a long implementation curve for the coiled-tubing industry. The next 12 months could bring upturns and downturns and greater or lesser volatility. Whatever may happen, the coiled-tubing industry’s record last year indicates that it will still be moving forward. Recommended additional reading at OnePetro: www.onepetro.org. SPE 179096 Localized Extreme Coiled-Tubing Wall Loss—Causes and Remediation Practices by Steven Craig, Baker Hughes, et al. SPE 179083 Novel Abrasive Perforating With Acid-Soluble Material and Subsequent Hydrajet-Assisted Stimulation Provide Outstanding Results in Carbonate Gas Well by Alejandro Chacon, Halliburton, et al. SPE 168294 Coiled-Tubing-Material Selection for Velocity Strings in Sour Brine Service by I. Ward, Shell Canada, et al.

Flow Assisted Corrosion of API 5L X-70 in Sour Brine induced by Pipe Flow Changes in a Jet Impingement Chamber

Flow Assisted Corrosion of API 5L X-70 in Sour Brine induced by Pipe Flow Changes in a Jet Impingement Chamber

Effect of Flow Rate on the Corrosion Products Formed on Traditional and New Generation API 5L X-70 in a Sour Brine Environment

Effect of Flow Rate on the Corrosion Products Formed on Traditional and New Generation API 5L X-70 in a Sour Brine Environment

New bis-di-organotin compounds derived from aminoacid-imine-hexadentate ligands. Multifunctional evaluation as corrosion inhibitors, antibacterials and asphaltene dispersants/inhibitors

A new class of bis-di-organotin (IV) compounds were synthesized in good yields (ca. 80%) by a one-step five molecules reaction in which intervene two molecular equivalents of leucine, one of 5,5′-methylene-bis-salicylaldehyde and either two of di-n-butyltin (IV) or diphenyltin (IV) oxides, that independently provided two bis-di-organotin derivatives. The structures of these two compounds were established by 1H, 13C and 119Sn NMR, as well as by IR and elemental analysis. In both cases the 119Sn chemical shifts are characteristic of pentacoordinated atoms in solution of non-coordinating solvent (CDCl3). Once characterized, the novel compounds were tested as corrosion inhibitors at 25, 50 and 100mgL−1 on mild steel surfaces in sour brine by linear polarization resistance and potentiodynamic curves. These experiments prove that these derivatives present top efficiencies of 54% and 68% for butyl and phenyl moieties, respectively. In addition, these two compounds were tested in vitro against Bacillus subtilis (Gram-positive, strain ATCC 6633), Escherichia coli (Gram-negative, strain DH5) and Pseudomonas fluorescens strains to assess their bactericidal activities, being more effective for the E. coli strain, at concentrations as low as 25mgL−1. Moreover, in order to correlate different activities and ascertain homologous action mechanisms, the two derivatives were tested for their asphaltene inhibition/dispersion activity. The results suggest that the presence of the four n-butyl moieties provide the needed amphiphillic balance to obtain better efficiencies in the tested activities.

Oxidation of sulfide ion in synthetic geothermal brines at carbon‐based anodes

AbstractGeothermal brines associated with natural gas extraction present an environmental problem because of the need to avoid the escape of toxic and odorous hydrogen sulfide. In this work, carbon‐based anodes (including graphite, granulated activated carbon (GAC), and industrial coke) were used in the electrochemical oxidation of sulfide ion in synthetic geothermal brines in both batch and flow cells, with a view to remediating this troublesome contaminant. Experiments were carried out in alkaline solution (to prevent volatilisation of H2S), in the absence or presence of added chloride ion and naphthenic acids (NAs). The product spread was variable due to the large number of competing reactions, including formation of polysulfide, oxidation to sulfate (either directly or via hypochlorination), sacrificial anode oxidation combined with sulfide trapping, and Kolbe oxidation of NAs combined with sulfide trapping. From the technological perspective, the product distribution is immaterial, because sour brines contain such high concentrations of inorganic and naphthenate salts that reinjection of the treated brine will always be required. The most efficient systems, on the basis of charge per mol sulfide remediated, employed packed bed reactors with ground coke or GAC anodes. In these reactors, the disappearance of sulfide ion was promoted, as expected, at low flow rate and high current. However, the packed beds were limited to low applied current, in order to avoid compromising the electrical conductivity of the anode bed by the production of gas (O2).

Electrochemical oxidation of sulfide ion in synthetic sour brines using periodic polarity reversal at Ebonex® electrodes

The Magneli phase Ti4O7 (Ebonex®) was used as both anode and cathode in the electrochemical oxidation of sulfide ion in alkaline solution in the absence and presence of chloride and naphthenate ions. Ebonex anodes gradually lost their activity through the formation of an over-oxidized surface layer, but their activity could be maintained by periodic polarity reversal. In the context of the current paradigm for the mechanistic behaviour of oxide-based anodes, Ti4O7 has properties that combine those of “inactive” anodes (formation of hydroxyl radicals) and “active” anodes (formation of a higher oxide at the surface), with the exception that the higher oxide in the case of Ti4O7 is TiO2, which is incapable of substrate oxidation. Sulfate is the major oxidation product, especially in the presence of chloride, an ubiquitous component of sour brines, via mediated electro-oxidation to hypochlorite. Unlike at boron-doped diamond anodes, at which sulfide is oxidized with near-quantitative current efficiency, significant parasitic oxidation of water to O2 occurs at Ebonex, and oxidation of sulfide requires ~16 F mol–1, corresponding to a 50% current efficiency.

Electrochemical oxidation of sulfide ion at a Ti/IrO2–Ta2O5 anode in the presence and absence of naphthenic acids

Electrochemical oxidation of sulfide ion at a Ti/IrO2–Ta2O5 anode followed partial order kinetics (between current and mass transport control) in the absence and presence of chloride ion and of naphthenic acids, at sulfide concentrations typical of sour brines. The desired outcome was to promote the 2-electron oxidation of sulfide to elemental sulfide rather than the 8-electron oxidation to sulfate. Although elemental sulfur accumulated to some extent at low conversion of sulfide, sulfate ion became the principal product as the reaction progressed. At high conversion, the overall current efficiencies were typically higher than 50%, with material balance about 90%. However, this anode material was gradually poisoned by sulfide in long term use.

Combining geologic data and numerical modeling to improve estimates of the CO2 sequestration potential of the Rock Springs Uplift, Wyoming

Abstract We present results from the first stages of a detailed three dimensional analysis of the geologic CO 2 sequestration potential of the Rock Springs Uplift (RSU), located in south-western Wyoming. This site is of particular interest because of the collocated 2.1 GW Jim Bridger coal burning power plant and the possibility of additional power plants being developed in the area to take advantage of the abundant coal reserves in the RSU region (i.e. the Southern California Edison CEPL project). The Rock Springs Uplift is a huge asymmetric dome structure with two superior target sequestration reservoirs located beneath a 1500 m thick sequence of Cretaceous shale. The target reservoirs, the Weber Sandstone and Madison Limestone, with thicknesses of greater than 200m and 75m respectively, are located at depths where pressures are well above the critical point of CO 2 . Seismic data reveal that the structure of the RSU creates an ideal trap for buoyant supercritical CO 2 . The target reservoirs currently contain high salinity sour brines (35,000-80,000 ppm) with little or no economic value. Reservoir continuity inferred from well logs and cores and high average measured porosity (10%) and permeability (10-75 md) led to initial screening estimates on the order of 26 billion tons of CO 2 for the storage capacity of the structure. This paper focuses on calculations that will help to refine the initial capacity estimates through the use of high resolution multiphase numerical models. First we present an analysis using a system level simulator, CO2-PENS, to differentiate between two injection depths in the Weber on the basis of the costs associated with on-site drilling and pipelines for a range of permeabilities. The deeper site is analogous to the subsurface near the Jim Bridger Power Plant (JBPP), while the shallower site is analogous to the crest of the RSU. Results of this analysis show that deeper injection may be more cost effective. Next, we develop a 3-D computational hydrostratigraphic model and simulate injection of CO 2 near the Jim Bridger Power Plant. Utilizing existing seismic and wellbore data, a geologic framework model has been created in EarthVision (i.e., 3D model building and visualization software). From this model, hydrostratigraphic units were extracted and a 3-D computational mesh for a 16×16 km section of the RSU structure was constructed. This model is used to simulate injection of 80% of the total CO 2 emissions from the 2.1 GW JBPP (483 kg/s or 15 Mt/year) into the Weber formation for two cases. The first case assumes a very high permeability in the Weber and needs only one injection well, while the second case assumes a lower permeability and uses 9 injection wells. The major differences between these two examples are the amount of CO 2 that dissolves into the formation brines and the areal extent of the resulting plumes. Because the low permeability case requires more injectors, the injected CO 2 is exposed to a larger volume of reservoir rock and leads to a higher percentage of the total injected CO 2 being dissolved in the formation water. The focused injection for the high permeability case leads to more CO 2 remaining in the supercritical state and longer up-dip transport. Finally, both cases show that both diffusive and advective transport into the surrounding strata may significantly increase the storage potential of the RSU.

A Bis(di‐n‐butyltin)–Quinone Derivative as a Simultaneous Chemo‐ and Bioactive Corrosion Inhibitor

AbstractThe bis(di‐n‐butyltin) derivative of 2,5‐bis(2‐hydroxyethylamino)‐1,4‐benzoquinone was synthesized and characterized by common spectroscopic techniques. In solution, discrete molecules with pentacoordinate tin atoms were observed, whereas the X‐ray diffraction analysis of the solid‐state structure revealed polymeric chains that were due to intermolecular Sn···O bonds. In vitro tests demonstrated that the tin compound displays bactericidal activity against a wide range of aerobic and anaerobic bacteria. Acute toxicity tests indicated that the di‐n‐butyltin compound has a relatively low toxicity level. The corrosion inhibition efficiency of the ligand and the tin compound were evaluated by polarization scans of mild steel samples that had been exposed to a sour brine environment. The tin–quinone compound showed good inhibition efficiency (about 75 %) at relatively low concentrations (25–50 ppm) and at different testing times (0.25–20 h).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Nanocap‐Shaped Tin Phthalocyanines: Synthesis, Characterization, and Corrosion Inhibition Activity

Thermal and microwave reactions between [PcSn(IV)Cl2] (1) and the potassium salts of eight fatty acids (2 a-h) led to cis-[(RCO2)2Sn(IV)Pc] compounds (3 a-h) in yields ranging from 54 to 90 %. Compounds 3 a-h were fully characterized by elemental analysis, spectroscopy (IR, UV/Vis, multinuclear NMR), and seven X-ray diffraction structures, whereby two different allotropes were observed in two cases. The two carboxylates in 3 have a cis anisobidentate binding mode, octacoordination of the tin atoms with square-antiprismatic geometry, and pi-electron-rich nanocap shapes. On account of the latter characteristics, 3 a-h compounds have anticorrosion properties. LPR and Tafel electrochemical methods were used to characterize the behavior of these derivatives in naturally aerated sour brine, which is a common environment in petroleum production and refinery operations. The measurement of the corrosion rate of carbon steel AISI 1018 in the presence of 3 a-h (500 ppm) gave efficiencies of 61-87 % for the inhibitor performance. Of the different derivatives examined, compounds 3 e and 3 h were the most effective corrosion inhibitor prototypes.

Phase Behavior of a Gas-Condensate/Water System

Summary Gas-condensate reservoirs are an essential part of Saudi Arabia's hydrocarbon resources. A good understanding of the effect of water on the phase-behavior properties of these hydrocarbons is essential for accurately forecasting the performance of the reservoirs with numerical simulators. In addition, the scaling and corrosion tendencies of the produced brine are strongly influenced by mass transfer with the hydrocarbon phase. This paper presents unique experimental phase-behavior data for a typical Saudi Arabian gas-condensate three-phase (aqueous/ condensate/gas) system. The objective of this work is to quantify the effect of the aqueous phase on gas-condensate fluid properties. The results show that appreciable amounts of carbon dioxide and methane are partitioned from the gas-condensate phase into the aqueous phase. Another important observation is the mass transfer of water into the condensate phase. The mass transfer between the condensate and aqueous phases results in a slight decrease in the gas/condensate ratio (GCR). The carbon dioxide in solution makes the brine acidic and can dissolve carbonate minerals from the formation (e.g., calcium carbonate). In addition, the acidic or sour brine will be quite corrosive. The experimental results are compared with equation-of-state (EOS) and other correlations published in the literature.

Ruthenium Enhanced Titanium Alloys

Several new, more highly corrosion resistant titanium alloys containing a nominal 0.1 weight per cent of ruthenium have been developed and evaluated for industrial service in corrosive environments. These improved ruthenium-enhanced α, α-β and β titanium alloys are lower in cost than the corresponding palladium-containing titanium alloys, and offer essentially the same corrosion performance in dilute reducing acids and hot brine environments. The titanium-0.1 ruthenium binary alloys can be cost effectively substituted for traditional titanium-palladium alloys and should represent a more attractive alternative to nickel-chromium-molybdenum alloys in hot, acidic brine applications. The corrosion database that has been established for the higher strength ruthenium-enhanced α-β and β titanium alloys in high temperature sweet and sour brines provides the basis for their selection for applications in the chemical process, oil/gas production, offshore and geothermal energy industries.

Corrosion Behavior of Low-Residual Carbon Steels in a Sour Environment

Abstract Potentiodynamic testing was used to study the corrosion performance of low-residual carbon steels in a sour brine, as typically encountered in Kuwaiti oil fields. Twenty-eight tests were performed to determine the effects of variations of carbon content from 0.1 to 0.4%; 1, 2, and 3% additions of cobalt; and 1, 2, and 4% additions of chromium. Results indicated carbon content decreased the corrosion rate in the absence of impurities and alloying elements because of the enhanced formation of corrosion products in the sour brine. The corrosion rate was about 254 μm/y (10 mpy). The addition of small amounts of Cr tended to increase the corrosion rate, regardless of the C content. For the 4% Cr samples, the corrosion rate averaged 2032 μm/y (80 mpy). From the values of βc for C steels and Cr-alloyed steels in the deaerated base brine, aerated base brine, and in the sour brine, the study concluded that Cr always depolarized the cathodic reaction independent of the environment. The Co-alloyed steels ex...