N80 Steel Research Articles

Investigation of the Tribological Properties and Corrosion Resistance of Multilayer Si-DLC Films on the Inner Surfaces of N80 Steel Pipes

In order to solve the problem of the corrosion and wear of N80 metal pipelines exposed to corrosive media and abrasive sand during the development of petroleum resources, the proposed solution involves utilizing HC-PECVD technology to deposit a series of multilayer Si-DLC films with varying thicknesses on the inner surfaces of the N80 steel pipes. This investigation systematically explored the microstructure, mechanical properties, tribological features, and corrosion resistance of the multilayer Si-DLC films. Remarkably, after coating the multilayer (Si-DLC)40 film on the inner wall of the N80 tube, the friction coefficient decreased from 0.7~0.75 to 0.2~3, and the wear rate decreased by two orders of magnitude. In addition, the corrosion current decreased by 50%, and the impedance doubled in a 3.5 wt% NaCl solution saturated with CO2. Thus, the multilayer (Si-DLC)40 film on the inner wall of the N80 tube exhibited superior tribological properties and exceptional corrosion resistance. These findings are anticipated to furnish valuable data and technical insights for mitigating corrosion in N80 steel pipes during petroleum exploitation.

A long-term effective solid capsule with matrix-type structure for the anticorrosion in oil and gas fields

The oil and gas industry frequently uses liquid corrosion inhibitors to reduce equipment and pipeline corrosion. However, this approach requires frequent additions, which are costly in terms of labor and materials. Solid corrosion inhibitor capsules (SCICs) have become an optimal alternative, as they provide long-term corrosion protection. However, the current encapsulation materials need to be modified for improving encapsulation capability. In this study, lauryl acrylate (LA) was grafted onto Ethylene-vinyl-acetates (EVA) to reduce its crystallinity and increase the interface force between EVA and oleic imidazoline (OIM). OIM was then encapsulated using the grafted EVA (EVA-g-LA) to form matrix-type solid capsules that possess the high encapsulation efficiency and long service life. The analysis with a UV–Vis spectrophotometer revealed that OIM had a stable release process from the SCIC matrix. Over a period of 91 days, the released OIM still had a high corrosion inhibition efficiency towards N80 steel (>80%). Using the prepared SCIC can reduce annual anticorrosion costs in oil and gas fields by 70%.

Inhibition Localized Corrosion of N80 Petroleum Pipeline Steel in NaCl-Na2S Solution Using an Imidazoline Quaternary Ammonium Salt

In this paper, the local corrosion inhibition effect of imidazoline on N80 oil pipeline steel in a NaCl-Na2S solution was studied by the simulated blocking tank cell method, and the corrosion processes of the cathode and anode in the blocking zone were simulated. The blocking corrosion behavior of the pipeline tubing steel N80 in simulated corrosion solutions without and with different concentrations of an imidazoline corrosion inhibitor was studied by chemical analysis and electrochemical analysis. The results show that in the three solution systems, after the anode polarization of the occluded cell, the solution in the occluded region is acidified, the pH value decreases sharply, the migration of Cl− and S2− increases, and the concentration is increased in the blocked area. After adding the imidazoline corrosion inhibitor, the imidazoline inhibitor can reduce the migration of small-radius anions (Cl− and S2−) to the occluded area, inhibit the acidification of the solution in the occluded area, and prevent the dissolution of metals in the occluded area. As a result, the corrosion of the occluded area is slowed down due to the change in the chemical and electrochemical state of the occluded area. In the three corrosion solution systems of 2% Na2S + 5% NaCl, 2% Na2S + 8% NaCl, and 2% Na2S + 10% NaCl, the imidazoline corrosion inhibitor can form an adsorption film on the metal surface, thereby increasing the polarization resistance and decreasing the corrosion rate. The addition of an imidazoline corrosion inhibitor can significantly increase the kinetic constant of anode polarization, which can effectively inhibit the local corrosion of N80 steel in these corrosion systems.

Synthesis of alkynyl alcohol derivatives and its corrosion inhibition on N80 steel in 5 M HCl

AbstractAlkynyl alcohol derivatives (N‐14) were synthesized by 2‐chloromethyl pyridine, propargyl alcohol and bromotetradecane and the structure was confirmed by 1H NMR, 13C NMR, MS and FTIR. The corrosion inhibition performance was evaluated by weight loss, Tafel polarization, EIS measurements and DFT quantum calculations. The results proved that N‐14 effectively inhibited the acid corrosion of N80 steel. The corrosion inhibition of N‐14 increased with its concentration and decreased with increasing temperature. A maximum of 99.56% inhibition efficiency was achieved using 5 × 10−5 mol/l of N‐14 at 60°C. Thermodynamic parameters showed that the adsorption of N‐14 on N80 steel is spontaneous and exothermic, conforming to Langmuir's adsorption. Electrochemical results showed that N‐14 behaved as a mixed‐type inhibitor. In addition, corrosion products produced on N80 steel surface were researched by SEM, XRD, UV and contact angle. At the same time, the corrosion inhibition mechanism was discussed.

Graphene oxide composite as a novel corrosion inhibitor for N80 steel in 15 % HCl: experimental and quantum chemical examinations

Abstract Graphene oxide (GO) consists of many functional groups containing oxygen that helps in its chemical modifications. Thus, we have explored the synthesis, and corrosion inhibition application of n-butylamine (nBA) functionalized GO, i.e., GO-nBA for N80 steel in the acidizing environment (15 % HCl). NMR and TEM characterized the GO-nBA. The performance of GO-nBA was evaluated via chemical and electrochemicals methods that are supported by surface examination techniques. The PDP results supports the mixed nature of protection ability of GO-nBA. Additionally, the excellency of GO-nBA is confirmed by the value of 93.93 % efficiency. The surface study furthermore represents smooth texture with the addition of GO-nBA. The computational analysis reveals excellent inhibitive performance of GO-nBA.

Ecofriendly β-N-butyl amino propionic acid as green corrosion inhibitor for N80 steel in CO2-saturated brine water

Ecofriendly β-N-butyl amino propionic acid as green corrosion inhibitor for N80 steel in CO2-saturated brine water

The power of novel morpholinyl Mannich bases to protect N80 steel against corrosion in acidic environment: DFT and SAR investigations

In this research article, we investigate the corrosion inhibition properties of two novel morpholinyl mannich bases namely 3-morpholino-1-phenylpropan-1-one (MB1) and 3-morpholino-1-phenyl-3-(pyridin-4-yl) propan-1-one (MB2). To establish a link between their corrosion inhibition efficacy and molecular characteristics, we employ a comprehensive approach involving the calculation of DFT-derived global and local reactivity parameters, as well as structure-activity relationship (SAR) indices. The obtained values of the global reactivity indices including dipole moment, energy gap, hardness, and softness show a positive correlation with the experimental data earlier reported. Fukui functions give a comprehensive reactive scheme exhibiting the atoms responsible for the electronic transfer. SAR parameters such as molecular volume (V), surface area (SA), and the polarizability (α) were found to be in good accordance with the experimental inhibition effectiveness order.

Study on wear resistance and toughness of calcium ion crosslinked cellulose nanofibers/multi-walled carbon nanotubes/hexagonal boron nitride hybrid reinforced Ni[sbnd]B composite coatings on N80 steel

This study developed a novel NiB/Ca-CNFs/MWCNTs/h-BN coating on N80 steel. The disadvantages of hexagonal boron nitride (h-BN) were improved by creatively combining multi-walled carbon nanotubes (MWCNTs), cellulose nanofibers (CNFs), and calcium ion cross-linking strategies. This led to the creation of Ca-CNFs/MWCNTs/h-BN hybrids, which were then doped into NiB coatings by varying pulse current densities. The results demonstrated that the surface morphology, mechanical properties, and toughness of the composite coating are all influenced by the Ca-CNFs/MWCNTs/h-BN doped at various current densities. Meanwhile, the NiB/Ca-CNFs/MWCNTs/h-BN (4 A/dm2) coating has the greatest microhardness (902.42 Hv) and the smallest friction coefficient (0.487) under reciprocating dry sliding friction conditions of Si3N4 friction balls. In addition, the results of nanoindentation and tensile tests show that the elastic modulus of NiB/Ca-CNFs/MWCNTs/h-BN (4 A/dm2) composite coating is 194.096 MPa and the tensile elongation is 12.2 %.

Temperature and Reaction Time’s Effects on N80 Steel Corrosion Behavior in Supercritical CO2 and Formation Water Environments

In the present study, an immersion experiment was carried out to examine how N80 steel corrodes when exposed to formation water containing dissolved CO2 and supercritical CO2 (Sc-CO2) along with water vapor. We employed electrochemical and surface analysis methods to examine the influence of various factors, including the temperature and duration of immersion, on the extent of corrosion. The results show that the corrosion patterns of N80 steel in a supercritical CO2 environment and CO2-saturated formation water differed significantly. The presence of similar corrosion features was suggested by the constant structure of the corrosion products identified in the formation water. However, the morphology of the corrosion product was complex in the supercritical CO2 environment, exhibiting features of pitting and localized corrosion. Furthermore, a non-linear trend in the corrosion rate was observed between 40 °C and 120 °C. Specifically, the rate of corrosion declined from 40 °C to 80 °C, but it then resumed its growth from 80 °C to 120 °C. These findings suggest that very high temperatures could lead to the destruction of corrosion products and subsequently enhance the corrosion process.

Protection of N80 steel from erosion-corrosion of geothermal water by nanoparticle-modified expoxy resin coatings

In order to investigate the erosion-corrosion resistance of nano-SiO2/EP composite coating and TiO2/EP composite coating in a geothermal environment, the coatings were subjected to potentiodynamic polarization curve tests, AC impedance tests, weightlessness tests, under different immersion time in geothermal water. The micro-morphology of the coating after erosion-corrosion was observed to evaluate the protective effect of the modified EP coating on N80 steel. The result showed that the addition of nanoparticles can improve the corrosion resistance of EP coatings to a certain extent, and the optimum addition amount of nanoparticles is 3%. In geothermal water containing sand, the corrosion inhibition efficiency of EP coatings modified by nanoparticles was above 99.99% except for the 1 wt% SiO2/EP composite coating. When the nanoparticle content is 1 wt%, the protective effect of nano-SiO2/EP composite coating is better than that of TiO2/EP composite coating, but the protective effect is opposite when the nanoparticle content is 3% and 5%, respectively.

Experimental study of CO2/O2 corrosion on pipelines during carbon capture, utilization and storage process

In this paper, high-temperature and high-pressure corrosion test was used to simulate the corrosion process of multi-component thermal fluid (CO2/O2/H2O) on oil pipes (N80 steel), casings (J55, TP90H, P110 steel, and transportation pipelines (20# steel) in the process of CCUS technology application. The results show that during the entire corrosion process, the oil layer casing and surface casing are corroded most seriously in this environment, and the corrosion forms of these five steel materials in the CO2/O2 environment are uniform corrosion and local corrosion, and the corrosion products mainly consist of FeCO3, Fe2O3, Fe3O4 and FeOOH crystals. These oxides form a double-layer film structure on the surface of the steel. The inner layer is denser and consists mostly of FeCO3 crystals, which has better protection against further corrosion of the internal steel. The outer layer is loose and porous, and its components are mostly FeCO3 crystals. Fe2O3, FeOOH, Fe3O4 and FeCO3 crystals, have poor corrosion protection for internal steel. Due to the difference in corrosion products of the inner and outer film layers, relatively obvious local corrosion appeared on the surfaces of the 5 steel materials.

Corrosion Evolution mechanism of N80 tubing steel under supercritical CO2 and H2S environment

The corrosion evolution mechanism of N80 tubing steel in 8 MPa supercritical CO2 and 0.1 MPa H2S environment was investigated. The results show that although the corrosion rate of N80 steel decreases with the prolonged corrosion time, it still maintains a high level of about 1.06 mm/y after a long period of 360 h. As the corrosion progresses, the corrosion products change from FeS to a mixture of FeS and FeCO3. The corrosion form of N80 steel changes from uniform corrosion to localized corrosion. The origin credited for localized corrosion is the detachment of large particles of FeS in the early corrosion stage. A double-layer film consisting of an outer layer of FeS and an inner layer of FeCO3 forms in the area of corrosion pits after a prolonged period of corrosion, which provides protection for the substrate, thereby causing the decrease of localized corrosion rate of N80 steel.

Influence of temperature on corrosion behavior of N80 Steel in multiple thermal fluid environment

During offshore oil production, O2 could be introduced into the multiple thermal fluid, and the temperature of the wellbore can reach up to 200°C, which may result severe corrosion of tubing. However, the corrosion mechanism of downhole pipes in such aggressive environment remains unclear in the high-temperature and high-pressure CO2-O2-H2O mixed environment. Herein, we investigated the corrosion behaviour of N80 steel with different temperatures in CO2-O2-H2O environment. The influence of temperature on composition and structure of the corrosion product film of N80 steel was characterized by scanning electron microscope, energy-dispersive spectroscopy and X-ray diffraction. The results show that the corrosion rates of N80 steel performed a downward trend with the increase of the temperature, but it increased slightly at 180°C. The corrosion rate of N80 steel was up to 1.6 mm/y at 60°C, owing to the damage to corrosion product film by O2 and reduced its protection at lower temperature. As the temperature increased, the formation of Fe3O4 enhanced the protection of the inner corrosion product film, thereby greatly reducing the corrosion rate. However, the product of (FeCa)CO3 in the corrosion film completely lost its protection at 180°C, and the corrosion rate increased slightly to 0.84 mm/y. With the temperature increased to 240°C the corrosion rate of N80 steel reduced to 0.24 mm/y on account of the formation of dense and complete Fe3O4.

Research on organic polyacid system suitable for water injection wells in low permeability reservoirs

Abstract Currently, the pollution and clogging problems of injection wells in low-permeability reservoirs are becoming more and more serious, leading to a series of issues, such as the decline of fluid production in wells and the increase of pressure in injection wells. To cope with these challenges, SY organic polyacid solution was developed in this paper and its dissolution efficiency was thoroughly investigated. The experimental results show that SY organic polyacid solution has a high dissolution rate of 88.7%, which exhibits excellent scale dissolution effect, and the solvent's dissolution has a good slow-release performance to ensure the long-lasting action time. At the same time, the corrosion rate of the solvent on the N80 steel sheet is only 0.6291 g/m²-h, much lower than the industry standard, which effectively protects the safety of the construction pipeline and production column. In addition, the dissolution rate of SY organic polyacid on clay reaches 10.14% in five minutes, indicating that it prevents the ground collapse caused by excessive dissolution of clay and has good profound penetration ability. In summary, using SY organic polyacid solution can effectively solve multiple problems such as reservoir mud, inorganic scale, organic scale and water injection fouling oil, which provides an effective solution for the contamination and clogging of water injection wells in low permeability reservoirs.

PH‐Responsive Chitosan Microspheres Loaded with Gemini Imidazolium‐Based Ionic Liquids as Smart Corrosion Inhibitors for N80 Steel in Hydrochloric Acid Solution

Chitosan microspheres (CSM) loaded with synthesized Gemini imidazolium‐based ionic liquids ([C2(Bim)2]Cl2@CSM and [C6(Bim)2]Br2@CSM) are constructed as smart corrosion inhibitors to protect N80 steel in hydrochloric acid solution. The optimal inhibition efficiency of [C2(Bim)2]Cl2 and [C6(Bim)2]Br2 at 300 mg L−1 reaches 94.68% and 95.96%, respectively, indicating mixed‐type inhibition behavior. On this basis, the prepared [C2(Bim)2]Cl2@CSM and [C6(Bim)2]Br2@CSM can proactively identify corrosive environments and protect the metal. The microspheres are pH‐responsive owing to the presence of Schiff‐base C═N bonds and the loaded inhibitors can be released rapidly in acidic environment. Released inhibitors are delivered to corroded sites and synergistically interact with decomposed microspheres for enhanced corrosion inhibition effect.

In-situ studies of rust layer formed on OCTG N80 steels alloyed with rare earth elements

In this study, the effect of rare earth (RE) alloying on the rust formed on N80 steels was investigated with in-situ micro-Raman spectroscopy and optical microscopy. Under potentiostatic tests at potentials representing accelerated conditions, there was formation of goethite phase on N80RE, while this protective and stable rust layer was not found on N80. The presence of goethite might explain the smaller corrosion rate of N80RE than N80 at later stages of corrosion, although the initial corrosion rate of N80RE was greater, which was probably due to RE modified inclusions.

Synergistic mechanism of ternary green corrosion inhibitors for N80 steel in 20 wt% HCl solution: Encapsulation and transportation of vanillin through micelles formed by ionic liquids

The encapsulation and directional transport to iron surface of green and poorly water-soluble vanillin were achieved by self-assembled micelles of ionic liquids formed by 1-hexadecyl-2,3-dimethyl imidazolium bromide and sodium dodecyl benzene sulfonate. The anti-corrosion performance of the system for N80 steel in 20 wt% hydrochloride solution at 90 ℃ was studied by weight-loss method, electrochemical tests, and surface analysis. The reaction activity of corrosion inhibitors and self-assembled film formation mechanism at high temperature were revealed by quantum chemistry and molecular dynamics simulation. The results shows that the system exhibits excellent synergistic corrosion inhibition effect via hydrogen bond, electrostatic interaction, and hydrophobic effect.

Investigating the steel–cement interface in high-temperature, high-pressure carbon dioxide environments

Abstract This study investigates the impact of high-temperature, high-pressure carbon dioxide on the steel-cement interface, crucial in engineering structures and carbon capture storage systems. Experiments conducted on N80 steel and ordinary portland cement in synthetic aquifer brine revealed that CO2 exposure significantly exacerbates steel corrosion and cement degradation. The corrosion current density of steel increased to 1.2 μA/cm2 after six months in CO2, compared to 0.3 μA/cm2 in unexposed samples. Cement samples showed a marked decline in mechanical properties, with hardness reducing from 1.25 GPa (giga-Pascal) in control samples to 0.65 GPa after six months. The steel—cement interface integrity also diminished, as evidenced by a decrease in acoustic impedance from 45.0 M-Rayl to 34.0 M-Rayl over six months. These results emphasize the need for advanced materials and strategies to enhance the durability and safety of structures in CO2-rich environments.

Laboratory Evaluation of a Low-Damage Authigenic Mud Acid System for Bai-823 Well Block.

Aiming at the problem of single and poor adaptability of Bai-823 plugging removal system, an authigenic mud acid system using methyl formate, ammonium chloride, and ammonium fluoride as raw materials is proposed, which can adapt to the temperature of 60-80 °C of the target reservoir and sandstone lithology. The acid-generating capacity of the authigenic acid system at different temperatures was evaluated. The results showed that the H+ concentration remained at 3.35 mol/L after 180 min at 80 °C, which indicated that authigenic acid could generate acid continuously and thus be competent for acidizing and plugging removal of further wells. The corrosion rate of authigenic acid to N80 steel was further investigated. When 2 wt % SA1-3B corrosion inhibitor was used, the corrosion rate was only 0.15 g/(m2·h). At the same time, the corrosion capacities of authigenic acid to rock core and scale samples were studied, which were 19.38 and 93.81%, respectively, indicating that the authigenic acid system realized pipeline and reservoir friendliness when it was able to effectively remove plugging. Finally, a core displacement experiment was carried out to simulate reservoir acidizing for plugging removal. The results showed that the core permeability increased from 1.00 to 1.63 after acidizing modification with authigenic acid. All of the above studies show that a kind of authigenic mud acid has been successfully prepared, and a new idea for the authigenic acid system has been proposed.

Corrosion behavior and mechanism of N80 steel caused by sulfate reducing bacteria in CO2-saturated shale gas field produced water at 60 ℃

The corrosion of steel caused by sulfate reducing bacteria (SRB) in shale gas environment is one of the big factors leading to the severe failure of pipeline steel. However, the related studies of SRB corrosion especially at a high temperature are still poor. This paper aims to investigate the effects of SRB on the corrosion behavior of N80 steel in CO2-saturated simulated shale gas produced water at 60 °C by weight loss, 3D microscope,electrochemical impedance spectroscopy (EIS) and polarization curves and so on. Results showed that the corrosion rate of N80 steel in the presence of SRB was greater than that of the abiotic control specimen. SRB cells and the inhibitive organics could have a competitive adsorption on the steel surface. The adsorption of inhibitive organics on steel in the abiotic condition caused a slight corrosion of the control specimen. While the adsorption of SRB cells as well as the subsequent formation of biofilm have accelerated the localized corrosion of specimen. Therefore, steel corrosion is accelerated in the presence of SRB at a high temperature.