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In the development and production of oil fields, the high sulfide-Cl - environment will cause severe corrosion of oil pipe steel. In order to provide technical basis for corrosion protection schemes in high sulfide-Cl - environment, the effects of sulfide content and Cl - concentration on the electrochemical corrosion behavior of J55 steel and 80S steel in high sulfide-Cl - corrosion environment were studied through dynamic potential polarization scanning and electrochemical impedance testing. The results show that as the sulfide content increases, the corrosion potential of J55 steel and 80S steel decreases, the corrosion tendency increases, the corrosion current density increases, the charge transfer resistance of AC impedance spectrum decreases, and the corrosion resistance increases. As the Cl - concentration increases, the corrosion potential of J55 steel increases and the corrosion tendency weakens, but there is no regularity in the corrosion potential Ecorr value of 80S steel. For corrosion current density, the corrosion current density i corr of J55 steel and 80S steel both increase with the increase of Cl - concentration. 80S steel has slightly stronger sulfur and corrosion resistance than J55 steel. [ABSTRACT FROM AUTHOR]

Titanium alloys have been widely used for drill pipes in complex structural wells and ultra-deep wells because they can provide great benefits in cost and operation in drilling systems due to their excellent properties such as high strength, low density, exceptional corrosion resistance and inherent flexibility. However, their wear behaviors during drilling have not been well understood by the communities. In this work, the effect of the impact force on the wear performance of titanium alloy drill pipes against steel casings was investigated through using a modified wet impact-sliding pin-on-disk test system, in which ZSA-3 titanium alloy was used for the pins and J55 steel was for the disks. The tests were conducted under simulated drilling mud conditions. As the impact force increases, the coefficient of friction tends to become stable and fluctuates slightly, and thus the wear rate of the tribo-pairs decreases gradually. The wear mechanism of J55 steel disks presents a transition from plastic deformation to plastic deformation accompanied by adhesive wear, while that of the titanium alloy pins changes from the plowing effect with adhesive wear to plastic deformation and adhesive wear. In addition, complex oxides will be formed on the surfaces of the tribo-pairs due to the oxidation of Ti and Fe during the wear process. The present results could provide as a fundamental guide for the drilling engineers in related industries for reducing casing wear in the drilling environment. [ABSTRACT FROM AUTHOR]

Oxygen-reducing air flooding is a low-permeability reservoir recovery technology with safety and low-cost advantages. However, in the process of air injection and drive, carbon in the air is oxidized through the crude oil reservoir to generate CO2, and this can cause serious corrosion in the recovery well. In this study, experiments on the corrosion of J55 tubular steel in a fluid environment with coexisting O2 and CO2 in an autoclave are presented. In particular, a weight loss method and a 3D morphometer were used to determine the average and the local corrosion rate. The corrosion surface morphology and composition were also measured by means of scanning electron microscopy (SEM) and an X-ray diffractometer (XRD). The corrosion pattern and morphological characteristics of J55 steel were analyzed in the O2/CO2 environment for different degrees of oxygen-reduction. As made evident by the experimental results, the corrosion products were mainly ferrous carbonate and iron oxide. In general, air injection increases the degree of oxygen reduction, from oxygen corrosion characteristics to CO2 corrosion-based characteristics. As a result, the corrosion product film becomes denser, and the corrosion rate is lower. [ABSTRACT FROM AUTHOR]

Studying casing corrosion mechanism and seeking alternative corrosion-resistant materials are the fundamental ways to slove the increasingly serious problem of casing corrosion in oilfields. Herein， by simulating the field corrosion conditions of Changqing Oilfield， the corrosion behavior of J55 and 3Cr materials in the environment of a CO2 partial pressure of 1.0 MPa， a H2S partial pressure of 0.3 MPa and a temperature of 60 ℃was studied. Additionally， the morphology and components of the corrosion products of these two materials were analyzed by means of scanning electron microscopy， energy spectroscopy and X-ray diffraction. Results showed that the enrichment of Cr element in the corrosion product film and the formation of Cr(OH)3 improved the stability and compactness of the corrosion products， making 3Cr exhibit better corrosion resistance than J55. In the environment containing both CO2 and H2S， H2S corrosion played a dominant role. The loose corrosion product film formed in CO2 corrosion made the uniform corrosion rates of J55 and 3Cr higher than those in environments containing H2S alone and containing both H2S and CO2.

The corrosion behaviour of J55 steel in typical high-water-cut oil wells and the inhibition effects of different types of corrosion inhibitors were investigated. Using electrochemical experiments, the effects of temperature, Cl−, HCO3−, Ca2+, Mg2+ and pH on the corrosion of J55 steel were studied. Under experimental conditions, the corrosion rate slowed with increasing pH value when the temperature increased from 35 °C to 70 °C. The corrosion rate also increased first and then decreased with increasing Cl−, Ca2+ and Mg2+ ion concentrations, which notably affected the distribution of corrosion pits on the surfaces of the steel. The protection performances of various corrosion inhibitors and corrosion products were evaluated through electrochemical measurements. The results showed that the CT-2, UT2-2 and YC-2 inhibitors had obvious effects on the corrosion prevention of the J55 steel. In particular, the corrosion inhibition efficiencies of the three kinds of carbon steel were remarkable and exceeded 84% when the UT2-2 concentration reached 0.18 g/L. [ABSTRACT FROM AUTHOR]

In this study, Corydalis yanhusuo extract acts as a green inhibitor for J55 steel in 3.5% NaCl solution saturated with CO2. Rapid resolution liquid chromatography shows the concentrations of Palmatine to be 0.6358 g/L, Tetrahydropalmatine 0.7715 g/L, and Corydaline 0.3755 g/L. Potentiodynamic polarization results suggest that Corydalis yanhusuo extract is a mixed-type inhibitor. The inhibition efficiency of Corydalis yanhusuo extract increases with the increase of concentration and reaches 92.36% at 5%v/v but decrease with the increased temperature. The inhibition efficiency is 69% at 80°C. The protective film formed on the metal surface was confirmed by Fourier transforms infrared spectroscopy, UV–visible, scanning electrochemical microscope and scanning electron microscope methods. The quantum chemical calculations predicate that Palmatine acts as the major component for inhibition performance.

In this study, Corydalis yanhusuo extract acts as a green inhibitor for J55 steel in 3.5% NaCl solution saturated with CO2. Rapid resolution liquid chromatography shows the concentrations of Palmatine to be 0.6358 g/L, Tetrahydropalmatine 0.7715 g/L, and Corydaline 0.3755 g/L. Potentiodynamic polarization results suggest that Corydalis yanhusuo extract is a mixed-type inhibitor. The inhibition efficiency of Corydalis yanhusuo extract increases with the increase of concentration and reaches 92.36% at 5%v/v but decrease with the increased temperature. The inhibition efficiency is 69% at 80°C. The protective film formed on the metal surface was confirmed by Fourier transforms infrared spectroscopy, UV–visible, scanning electrochemical microscope and scanning electron microscope methods. The quantum chemical calculations predicate that Palmatine acts as the major component for inhibition performance. [ABSTRACT FROM AUTHOR]

In this study, Corydalis yanhusuo extract acts as a green inhibitor for J55 steel in 3.5% NaCl solution saturated with CO2. Rapid resolution liquid chromatography shows the concentrations of Palmatine to be 0.6358 g/L, Tetrahydropalmatine 0.7715 g/L, and Corydaline 0.3755 g/L. Potentiodynamic polarization results suggest that Corydalis yanhusuo extract is a mixed-type inhibitor. The inhibition efficiency of Corydalis yanhusuo extract increases with the increase of concentration and reaches 92.36% at 5%v/v but decrease with the increased temperature. The inhibition efficiency is 69% at 80°C. The protective film formed on the metal surface was confirmed by Fourier transforms infrared spectroscopy, UV–visible, scanning electrochemical microscope and scanning electron microscope methods. The quantum chemical calculations predicate that Palmatine acts as the major component for inhibition performance. [ABSTRACT FROM AUTHOR]

Highlights • J55 steel protection in oil field formation water saturated with carbon dioxide by ATs molecules. • Potentiodynamic polarization curves reveal that the actions of inhibitors are mixed type but cathodically predominat. • Examination of surface morphology by SEM, SECM and AFM. • Correlation of experimental results with Quantum chemical, molecular dynamic stimulation, radial distribution functions and mean-square displacement results. Abstract Present paper deals with the performance of imidazoline derivatives (ATs) as corrosion inhibitor for J55 steel in oil field formation water saturated with CO 2. The inhibition effectiveness of AT-1 was found to 90% at 400 mg/L. Inhibitors addition decreases cathodic as well anodic current densities, and significantly strengthens impedance parameters. Contact angle and SEM/AFM/SECM measurements predicts the hydrophobicity and surface morphology of steel, respectively. Density functional theory (DFT) and molecular dynamic simulation (MD) calculations were performed to investigate the adsorption mechanism of ATs. Radial distribution function (RDF) and the mean-square displacement (MSD) were used to study inhibitor/metal interactions and migration rate of corrosive species, respectively. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

As the core technology of petroleum extraction engineering in the 21st century, Solid Expandable Tubular (SET) technology is applied to drilling, well completion, and cementing. However, the expansion process for tubulars in site operation may well lead to stress concentration, leakage, or even fracture failure in thread joints of the tubular assembly due to the irregular deformation of thread teeth. With the aim of studying the issue with regard to the thread joint of J55 steel expandable tubulars, this study extended a series of finite element models using the commercial software ABAQUS to investigate the structural response of tubulars during the expansion process. The simulation results include the stress evolution, deformation of the thread joint of the tubular assembly, and the effect of expansion cone geometry on the expansion consequences. A laboratory experiment was performed to validate the validity of the simulated solution. It was found from results that both the axial and hoop compressive stress concentrations were generated in the thread teeth edges near the contact surfaces of threads during the expansion process due to the mutual squeezing of box and pin thread teeth. An increase of the tubular diameter led to a reduction of wall thickness and axial length due to the law of volume-constancy. The expansion process resulted in a deterioration of the contact condition between the thread teeth. A cone angle of 9° and sizing section length of 65–75 mm were the optimal choice of the geometric size of the expansion cone according to their superior analytical results. [ABSTRACT FROM AUTHOR]

Fluvoxamine (FLU), a non-toxic compound was investigated as an alternative anti-corrosive additive for inhibition of J55 steel corrosion in acidic oil well treatment fluids. The aggressive fluid was simulated using 15% and 1 M HCl. Corrosion of the steel was monitored by Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), Linear Polarization Resistance (LPR), Electrochemical Frequency Modulation (EFM) and Weight Loss (WL) techniques. UV–Vis spectroscopy provided evidence of formation of a complex surface film due to adsorption of FLU on the J55 steel surface. The adsorption process was both physical and chemical in mechanism as best approximated by the Langmuir adsorption isotherm. The adsorption was also spontaneous and exothermic in the direction of increase in entropy of the bulk phase. Maximum inhibition efficiency was obtained with 1.0 μM FLU and decreased from 91.5% to 78.0% when concentration of HCl was increased from 1 M to 15% at 30 °C. Effectiveness of FLU declined with an increase in temperature and improved with an increase in concentration of FLU. Blending of FLU with some intensifiers improved the efficiency from 68% and 40% to 88% and 72% in 1 M and 15% HCl respectively at 90 °C. EIS measurement reveals that the corrosion process was controlled by charge transfer process. PDP measurements showed that FLU acts as a mixed type inhibitor. Inhibition efficiency values obtained from the different techniques were comparable. SEM micrographs of J55 steel surface indicate good surface protection of FLU. Theoretical calculations were performed using Material Studio Acceryls 7.0 to relate electronic properties of FLU with its structure. [ABSTRACT FROM AUTHOR]

The corrosion inhibition performance of three novel imidazole derivatives namely 2-(4-methoxyphenyl)-4,5-diphenyl-imidazole (M-1), 4,5-diphenyl-2-( p -tolyl)-imidazole (M-2) and 2-(4-nitrophenyl)-4,5-diphenyl-imidazole (M-3) for J55 steel in CO 2 saturated brine solution was studied by weight loss method, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, scanning electrochemical microscopy (SECM), contact angle, scanning electron microscope (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and quantum chemical calculation. M-1 exhibited the best inhibition efficiency of 93% at 400 mg/L concentration. The adsorption of the imidazole derivatives obeyed the Langmuir adsorption isotherm. Contact angle measurement reveals the hydrophobic nature of J55 steel in presence of inhibitors. Quantum chemical calculation well supports the experimental results. [ABSTRACT FROM AUTHOR]

Corrosion inhibition of J55 steel in 3.5 wt.% NaCl solution saturated with CO 2 by the three Porphines 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (P1), 5,10,15,20-Tetraphenyl-21H,23H-porphine (P2), 5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine (P3), electrochemical impedance spectroscopy (EIS), Contact angle measurement, scanning electrochemical microscopy (SECM), and atomic force microscopy (AFM). Adsorption of such Porphines on the J55 steel surface obeyed to the Langmuir adsorption isotherm. Atomic force microscopy (AFM), SECM, and Contact angle results confirm the formation of inhibitor film on J55 steel surface thereby mitigating corrosion. [ABSTRACT FROM AUTHOR]

1,2,4,7,9,10-Hexaazacyclo-pentadeca-10,15-dien-3,5,6,8-tetraone (HPT) a macrocyclic compound has been studied using electrochemical methods and scanning electrochemical microscopy (SECM) techniques. The R ct values increased and C dl values decreased with the increase in concentration of the inhibitor. The corrosion inhibition of J55 steel in 3.5 wt.% NaCl solution saturated with CO 2 by polarization studies revealed that HPT acted as a mixed type inhibitor. The adsorption of HPT on the J55 steel surface obeyed the Langmuir adsorption isotherm. The thermodynamic parameters ( K ads , Δ G ° ads ) were also computed and discussed. [ABSTRACT FROM AUTHOR]

The influence of polymer of 2-(methoxycarbonyl)-1-propene (MMA) monomer and poly N -vinyl-2-pyrrolidone (NVP) monomer namely poly(methyl methacrylate- co - N -vinyl-2-pyrrolidone) or P(MMA- co -VP) on corrosion of J55 steel in 3.5 wt.% NaCl solution saturated with CO 2 was evaluated using Fourier transform infrared spectroscopy (FTIR), Tafel polarization, electrochemical impedance spectroscopy (EIS), UV–visible, and scanning electron microscopy (SEM). Results obtained showed that polymer is a mixed type inhibitor as the maximum— E corr displacement is 58 mV. The adsorption of the extract on the J55 steel surface obeyed the Langmuir adsorption isotherm. SEM and UV–visible spectroscopy studies reveal that the surface of metal is quite unaffected after the use of P(MMA- co -VP) in 3.5% NaCl solution saturated with CO 2 . [ABSTRACT FROM AUTHOR]

• The effect of Vincamine (VCA) as inhibitor for the corrosion of J55 steel in 1 M HCl was examined utilizing gravimetric and electrochemical methods. • Surface morphology was studied using fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. • Polarization results indicated that VCA exhibited mixed-type corrosion inhibitor characteristics. • The adsorption of VCA on the surface of J55 steel followed the Langmuir isotherm. • Quantum chemical studies and molecular dynamics (MD) simulation were used to relate the restraint capability of VCA with its electronic structural parameters. The effect of Vincamine (VCA) as an inhibitor for the corrosion of J55 steel in 1 M HCl was examined utilizing gravimetric and electrochemical methods. Surface morphology was studied using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The outcome showed that VCA hindered the dissolution of J55 steel in the acidic medium. From the gravimetric method, results showed that inhibition efficacy depended on the concentration of VCA and the temperature of the medium. Electrochemical impedance spectroscopy (EIS) studies revealed a rise in resistance of charge transfer, with a corresponding decline in the capacitance of double layer when there is a rise in the concentration of VCA. Polarization results indicated that VCA exhibited mixed-type corrosion inhibitor characteristics. The range of inhibition efficiencies obtained is; 79.4 to 90.2% for EIS studies, 76.0 to 91.4% for weight loss and 77.4 to 88.6% for polarization studies at 30 °C. SEM, FTIR, and AFM investigations established the adsorption of VCA on the surface of J55, thereby reducing the deterioration reaction. The adsorption of VCA on the surface of J55 steel followed the Freundlich adsorption isotherm. The adsorption characteristics were theoretically evaluated by quantum chemical studies and molecular dynamics (MD) simulation to relate the restraint capability of VCA with its electronic structural parameters. [ABSTRACT FROM AUTHOR]

Benzimidazole derivatives were synthesized, characterized, and tested as a corrosion inhibitor for J55 steel in a 3.5 wt % NaCl solution saturated with carbon dioxide. The experimental results revealed that inhibitors are effective for steel protection, with an inhibition efficiency of 94% in the presence of 400 mg/L of inhibitor. The adsorption of the benzimidazole derivatives on J55 steel was found to obey Langmuir's adsorption isotherm. The addition of inhibitors decreases the cathodic as well anodic current densities and significantly strengthens impedance parameters. X-ray photoelectron spectroscopy (XPS) was used for steel surface characterization. Density functional theory (DFT) and molecular dynamic simulation (MD) were applied for theoretical studies. [ABSTRACT FROM AUTHOR]

Benzimidazole derivatives were synthesized, characterized, and tested as a corrosion inhibitor for J55 steel in a 3.5 wt % NaCl solution saturated with carbon dioxide. The experimental results revealed that inhibitors are effective for steel protection, with an inhibition efficiency of 94% in the presence of 400 mg/L of inhibitor. The adsorption of the benzimidazole derivatives on J55 steel was found to obey Langmuir's adsorption isotherm. The addition of inhibitors decreases the cathodic as well anodic current densities and significantly strengthens impedance parameters. X-ray photoelectron spectroscopy (XPS) was used for steel surface characterization. Density functional theory (DFT) and molecular dynamic simulation (MD) were applied for theoretical studies.