Research Institute of Natural Gas Technology

A novel Ca(2+) ion responsive particulate emulsifier, which is based on copolymer nanoaggregates, is reported in this work. Results from dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM) indicate that the formation of poly (4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA) nanoaggregates is strongly dependent on Ca(2+) concentration. The PSSMA copolymer only aggregates above a critical Ca(2+) concentration (0.2 M) with an average diameter of 10-40 nm. After dilution with water, PSSMA nanoaggregates are rapidly redissolved again. On the basis of the properties of PSSMA nanoaggregates, Ca(2+) ion responsive Pickering emulsions were successfully prepared. At high Ca(2+) concentrations, the emulsions with high stability against coalescence can be prepared with the size in the submicrometer range as determined by DLS. Cryo-TEM and dynamic interfacial tension results confirm the adsorption of PSSMA nanoaggregates at the interface, which is the key to the stability of the emulsions. More importantly, rapid demulsification can be achieved by dilution with water on demand. It is because, upon dilution with water, PSSMA nanoaggregates undergo a transition from stable nanoaggregates to individual polymer chains, which leads to interfacial desorption of nanoaggregates and rapid demulsification of emulsions. Thus, this finding presents a new manipulation on emulsion stability and is expected to provide a useful guidance in the fields of oil recovery, food science, environment protection, and so on.

The ingress of oxygen into pressure vessels used in oil & gas production and transportation could easily result in serious corrosion. In this work, the corrosion behaviors of Q345R steel at the initial stage in 1 wt.% NaCl solution were investigated using electrochemical techniques. The effects of oxygen concentration, temperature and pH on corrosion behaviors were discussed. Simultaneously, a numerical model based on the mixed potential theory was proposed. The results show that the proposed model accords well with the experimental data in the pH range from 9.0 to 5.0. In this pH range, the oxygen reduction reaction, H⁺ reduction, water reduction, and iron oxidation can be quantitatively analyzed using this model. However, this model shows a disagreement with the experimental data at lower pH. This can be attributed to the fact that actual area of reaction on the electrode is much smaller than the preset area due to the block effect resulted from hydrogen bubbles adsorbed on the electrode surface.

Abstract Aiming at the current situation that the existing acidizing corrosion inhibitors are difficult to apply in high temperature, high concentration acid, and other complex conditions, this article uses nano-SiO 2 as the core and preferably functional monomers to synthesize nano-SiO 2 @octadecylbisimidazoline quaternary ammonium salt (nano-SiO 2 @OBQA). Analytical methods such as nuclear magnetic resonance, infrared, and scanning electron microscopy were used for characterization. The corrosion inhibition performance of the N80 steel sheet by nano-SiO 2 @OBQA in 20% concentrated hydrochloric acid was studied using the high-temperature corrosion testing machine and adsorption isotherm model combined with quantum chemistry calculations to explore its mechanism of action. The results show that nano-SiO 2 @OBQA has good high-temperature resistance. When the temperature is 180℃ and the dosage of nano-SiO 2 @OBQA is 4%, the corrosion inhibition rate is 61.42 g·m −2 ·h −1 . Studies have shown that the adsorption of nano-SiO 2 @OBQA on the surface of the N80 steel sheet follows the Langmuir isotherm adsorption model, which is spontaneous chemical adsorption.

Sulphide gas is an impurity that affects the quality of natural gas, which needs reasonable storage and transportation. In this work, we investigated the adsorption structure and electronic behavior of hydrogen sulfide (H2S), carbonyl sulfur (COS), and methyl mercaptan (CH3SH) on sulphide gas molecules on pure and vacant α-Fe2O3(001) surfaces by density functional theory with geometrical relaxations. The results show that H2S and CH3SH are mainly adsorbed in the form of molecules on the pure Fe2O3(001) surface. On the vacant α-Fe2O3(001) surface, they can be adsorbed on Fe atoms in molecular form and by dissociation. The absolute value of the adsorption energy of H2S and CH3SH on the vacancy defect α-Fe2O3 surface is larger, and the density of states show that the electron orbital hybridization is more significant, and the adsorption is stronger. The charge differential density and Mulliken charge population analysis show that the charge is rearranged and chemical bonds are formed. The affinity of H2S to the vacancy α-Fe2O3(001) surface is slightly higher than that of CH3SH, while COS molecules basically do not adsorb on the α-Fe2O3(001) surface, which may be related to the stable chemical properties of the molecules themselves.

Abstract The development and stimulation of oil and gas fields are inseparable from the experimental analysis of reservoir rocks. Large number of experiments, poor reservoir properties and thin reservoir thickness will lead to insufficient number of cores, which restricts the experimental evaluation effect of cores. Digital rock physics (DRP) can solve these problems well. This paper presents a rapid, simple, and practical method to establish the pore structure and lithology of DRP based on laboratory experiments. First, a core is scanned by computed tomography (CT) scanning technology, and filtering back-projection reconstruction method is used to test the core visualization. Subsequently, three-dimensional median filtering technology is used to eliminate noise signals after scanning, and the maximum interclass variance method is used to segment the rock skeleton and pore. Based on X-ray diffraction technology, the distribution of minerals in the rock core is studied by combining the processed CT scan data. The core pore size distribution is analyzed by the mercury intrusion method, and the core pore size distribution with spatial correlation is constructed by the kriging interpolation method. Based on the analysis of the core particle-size distribution by the screening method, the shape of the rock particle is assumed to be a more practical irregular polyhedron; considering this shape and the mineral distribution, the DRP pore structure and lithology are finally established. The DRP porosity calculated by MATLAB software is 32.4%, and the core porosity measured in a nuclear magnetic resonance experiment is 29.9%; thus, the accuracy of the model is validated. Further, the method of simulating the process of physical and chemical changes by using the digital core is proposed for further study.

Polyaniline-coated Ti 3 C 2 Tx particles (TPi) endowed the electrophoretic deposited epoxy coating with efficient physical shielding and corrosion inhibition capacities to improve the corrosion protection ability. Ti 3 C 2 Tx of few/single layers was prepared and TPi particles were synthesized by in-situ polymerization of polyaniline on Ti 3 C 2 Tx surface. Characterization results indicated the successful synthesis of TPi material. TPi/epoxy coating was prepared on P110 steel sheet through cathodic electrophoretic deposition method, and the protection ability was tested by electrochemical impedance spectroscopy (EIS) and saline immersion test. EIS results of the complete coating showed that impedance modulus at low frequency (0.01 Hz) of TP7 coating was 3.92 × 10 8 Ω cm 2 after soaking for 20 d, which was higher than 2.82 × 10 6 Ω cm 2 of neat epoxy coating (NEP), indicating better protection performance. The results of impedance spectrum of scratched coating showed that TP7 coating had obvious corrosion inhibition effect, which was attributed to the passivation effect of polyaniline to promote the conversion of loose corrosion products into dense layers. This research provided a new approach to apply Ti 3 C 2 Tx into the electrophoretic deposited epoxy coating with corrosion inhibition effect.

The transmission medium of natural gas gathering and transportation pipelines usually contains corrosive gases, which will cause serious corrosion on the inner wall of the pipelines when they coexist with water. Therefore, it is necessary to add corrosion inhibitor to form a protective film to protect the pipeline. The distribution of corrosion inhibitors in a gathering and transportation pipeline in Moxi gas field was studied by combining experiment and simulation. The Pearson function was used to calculate the experimental and simulation results, and the correlation was more than 80%, indicating a high degree of agreement. The simulation results show that: ① The larger the pipe angle, filling speed and gas flow rate, the smaller the particle size, the better the distribution of corrosion inhibitor particles in the pipe. The filling amount will affect the concentration, but the distribution trend is unchanged; ② A method to determine the filling mode based on the loss was proposed, and for this pipeline, the loss of corrosion inhibitor was determined to be 5.31 × 10−3 kg/s, and the filling amount was recommended to be adjusted to 20 L/h, which has certain guiding significance for the actual filling strategy of pipeline corrosion inhibitor.

Aiming at the challenge that environmental protection and high-temperature fluid loss reduction performance of the traditional water-based drilling fluid treatment agent are difficult to balance, our studies added psyllium husk as a high-temperature-resistant and environmentally friendly filtrate reducer to a water-based drilling fluid. The composition, physical and chemical properties, and microstructure of psyllium husk are characterized. Then, the effects of psyllium husk after hot rolling at different temperatures on the rheological properties and fluid loss properties of bentonite-based slurry are evaluated. The results show that the psyllium husk added to the bentonite-based slurry can effectively improve the rheological properties and fluid loss properties of the bentonite-based slurry, and the temperature resistance can reach 160 °C. After hot rolling at 160 °C, adding 1 w/v % psyllium husk can reduce the API fluid loss and high-temperature and high-pressure fluid loss of the bentonite-based slurry by 76.04 and 56.91%, respectively, showing excellent fluid loss reduction performance at high temperatures. The branched structure and uronic acid of psyllium husk can inhibit the degradation of its own molecular structure to a certain extent, which is the fundamental reason why psyllium husk still has excellent fluid loss reduction performance at high temperatures. Psyllium husk is expected to replace some traditional synthetic polymers and be used in environmentally friendly high-temperature-resistant water-based drilling fluids.

Abstract A bimannich-based TZBM containing a thiazole ring was obtained by synthesis of mannich bases. TZBM featured a stable structure at 260 °C, and corrosion inhibition effect on carbon steel in a gas–liquid environment with Cl − + H 2 S + CO 2 at 180 °C. By analyzing the weight loss of steel exposed to different TZBM concentrations, the coverages of the inhibitor adsorbed on the surfaces were determined, and the results conformed to Langmuir isotherm model. Furthermore, the negative Gibbs free energy indicated that the adsorption was a spontaneous process. Graphical Abstract

ABSTRACT A water‐miscible nonionic surfmer (AC‐TX100) was synthesized based on Triton X‐100 and acryloyl chloride. Then, a terpolymer P(AM/AA/AC‐TX100) was synthesized by free radical polymerization in aqueous solution and intended to be used as drag reducing agent (DRA). The DRA was defined to be P(AM 87.32 /AA 12.46 /AC‐TX100 0.22 ) according to 1 H NMR and elemental analysis, the molecular weight was 2.12 × 10 6 g/mol according to scattering method. DRA shows excellent performance in drag reduction (DR). The highest DR rate of 76% can be obtained when DRA concentration is 0.023% in fresh water; while in brine containing 3% NaCl, DR rate decreases, and it is necessary to increase the concentration to 0.05% to ensure that DR rate is higher than 70%. SEM and cryo‐TEM show that DRA forms a network structure in aqueous solution, and the tightness of this structure has a direct influence on DR performance. Specifically, DRA molecules stretch into the whirlpools generated by water at high flow rates, reducing the quantity and intensity of whirlpools, thereby lowering the energy loss and the friction. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48362.

Digital rock physics (DRP) is a paramount technology to improve the economic benefits of oil and gas fields, devise more scientific oil and gas field development plans, and create digital oil and gas fields. Currently, a significant gap is present between DRP theory and practical applications. Conventional digital-core construction focuses only on simple cores, and the recognition and segmentation effect of fractures and pores of complex cores is poor. The identification of rock minerals is inaccurate, which leads to the difference between the digital and actual cores. To promote the application of DRP in developing oil and gas fields, based on the high-precision X-ray computed tomography scanning technology, the U-Net deep learning model of the full convolution neural network is used to segment the pores, fractures, and matrix from the complex rock core with natural fractures innovatively. Simultaneously, the distribution of rock minerals is divided, and the distribution of rock conditions is corrected by X-ray diffraction. A pore–fracture network model is established based on the equivalent radius, which lays the foundation for fluid seepage simulation. Finally, the accuracy of the established a digital core is verified by the porosity measured via nuclear magnetic resonance technology, which is of great significance to the development and application of DRP in oil and gas fields.

In this study, propylamine and ethylenediamine intercalated α-ZrP nanocomposites (denoted by P-α-ZrP and E-α-ZrP, respectively) were synthesized. The effects of propylamine and ethylenediamine intercalated α-ZrP nanocomposites and their reinforcements on the corrosion resistance and mechanical properties of Ni-B coatings were investigated and compared. The morphology and structure of the three composites were characterized using transmission electron microscopy , atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, infrared spectroscopy, thermogravimetric analysis , and particle size analysis . Both propylamine and ethylenediamine intercalation increase the layer spacing of α-ZrP, but do not change the lamellar structure of α-ZrP. The EIS test results show that both Ni-B/P-α-ZrP and Ni-B/E-α-ZrP composite coatings have significantly lower corrosion rates than Ni-B and Ni-B/α-ZrP composite coatings. Compared to Ni-B/α-ZrP, the corrosion rates are reduced by 32 % and 76 % respectively. The R ct values for Ni-B/P-α-ZrP and Ni-B/E-α-ZrP composite coatings are also distinctly higher than Ni-B/α-ZrP, with Ni-B/E-α-ZrP having the highest values. In addition, Ni-B/P-α-ZrP and Ni-B/E-α-ZrP composite coatings are both harder than Ni-B/α-ZrP and have lower average coefficients of friction and wear rates than Ni-B/α-aZrP. Among them, the Ni-B/E-α-ZrP composite coating has the highest microhardness (1163.64 ± 21.20 HV) and the best wear resistance. The wear rate is reduced by 87 % and 65 % compared to Ni-B and Ni-B/α-ZrP composite coatings respectively. In conclusion, both P-α-ZrP and E-α-ZrP are better than α-ZrP in terms of enhancement, with E-α-ZrP being the best.

The lithium resource is a crucial national strategic asset, and China's salt lakes are abundant in lithium. Efficient extraction of lithium from these salt lakes holds immense significance. Among the various methods available for the extraction of lithium from salt lakes, the adsorption method stands out due to its high selectivity, economic viability, and advanced process maturity. The key lies in developing high-performance adsorption materials, with lithium titanium oxide (LTO)-type lithium-ion sieves (LIS) being considered promising candidates. Therefore, we have concentrated on the structure and adsorption mechanism of titanium-based ion sieves and the preparation methods of different titanium oxide precursors in this review. Moreover, two modification methods, i.e., ion doping and surface coating, are discussed. Lastly, the insufficiency of current research is proposed, and the optimization and application of titanium-based LIS are prospected.

Improving the dispersibility and compatibility of nanomaterials in water-borne epoxy resins is an important means to improve the protection ability and corrosion resistance of coatings. In this study, glycine-functionalized Ti 3 C 2 T x (GT) was used to prepare an epoxy composite coating. The results of Fourier transform infrared spectroscopy and X-ray diffraction showed that glycine was successfully modified. The scanning electron microscopy and transmission electron microscopy results showed that the aggregation of Ti 3 C 2 T x was alleviated. Electrochemical impedance spectroscopy test results show that, after 60 days of immersion, GT coating still shows the best protection performance, and the composite coating | Z | f = 0.01 Hz is 3 orders of magnitude higher than that of the pure epoxy coating. This is mainly because, after adding glycine, the −COOH group on the surface of glycine binds to the −OH group on the surface of Ti 3 C 2 T x, improving the aggregation of Ti 3 C 2 T x itself. At the same time, the −NH group of glycine can also participate in the curing reaction of epoxy resin to strengthen the bonding strength between the coating and the metal. The good dispersion of GT in epoxy resin makes it fill the pores and holes left by epoxy resin curing and strengthen the corrosion resistance. The easy availability and green properties of glycine provide a simple and environmentally friendly method for the modification of Ti 3 C 2 T x .

Abstract A shale gas gathering and transportation pipeline in a good block in Sichuan Province started leaking after less than a year of operation. To investigate the causes of corrosion of the sulfate‐reducing bacteria (SRB), optical microscopy, scanning electron microscopy, and X‐ray diffraction were used to analyze the corrosion and perforation of the shale gas surface pipeline in conjunction with bacterial corrosion simulation experiments. The results showed that the pipeline material (L360N) conformed to the requirements of the American Petroleum Institute 5 L standard and that extracellular polymeric substances were present in the corrosion pits. The corrosion products mainly included FeCO 3 , FeS, CaCO 3 , MgCO 3 , and Fe mineralization. At 40°C, the uniform corrosion rate of L360N in the simulation experiment was 0.234 mm/a, and the local corrosion rate was 0.458 mm/a. SRB, saprophytes, and iron bacteria were detected in the on‐site water medium and corrosion products, indicating that the main causes of shale gas pipeline corrosion are bacterial and CO 2 corrosion.

Methane (CH 4 ) pyrolysis via molten media catalysis presents a transformative coke-free pathway for carbon-neutral hydrogen production and high-value carbon capture, yet its industrial scalability remains constrained by energy-intensive ultrahigh temperature requirements. Recent breakthroughs in multicomponent molten systems (i.e., binary, ternary, and quaternary) have shown great potential for effective CH 4 pyrolysis at a moderate temperature, opening up exciting possibilities for the industrialization of CH 4 pyrolysis. However, the combinatorial complexity of element selection and atomic disorder in molten media, coupled with the limitations of empirical experimentation and conventional computational methods, present great hurdles for multicomponent molten catalysts design. With the development of artificial intelligence and data technology, the data-driven strategy offers a promising alternative to the traditional experiment/theory approach. From this perspective, we expound and emphasize the data-driven approach for enhancing molten media catalysts discovery and advancing the industrialization development of CH 4 pyrolysis. We discuss the capacity of this approach to explore the design space along with several data-guided strategies tackling the existing challenges associated with molten catalysts design.

Abstract ZnO nanomaterials with the stereochemical structure were becoming a research focus in the scope of photocatalytic materials, but the ZnO was sensitive to UV light rather than the solar light source, which considerably prohibited its extended application. ZnO nanomaterials coupled with other nanomaterials could generate the alternative composite heterojunction nanomaterials to promote the photocatalytic activity. Herein, we reported two facile and feasible synthesis methods to fabricate TiO 2 /ZnO cube nanocomposites and Ag/ZnO hollow spheres by hydrothermal reaction and chemical deposition, respectively. In this regard, these composited nanomaterials have been successfully fabricated with high purities, good morphology, and crystal structure. Noticeably, in contrast with TiO 2 /ZnO and Ag/ZnO bulk nanocomposites, the Ag/ZnO hollow spheres could offer the higher activity for RhB degradation under the visible light. Moreover, the photocatalytic performance of Ag/ZnO for RhB degradation could be improved synergistically, and the effect of RhB degradation was highest when the Ag mass ratio was modulated at 10% in the sample. Furthermore, it remained a high photocatalytic efficiency even after four cycles. This protocol provided an approvable approach to fabricate efficient photocatalysts with persistent photostability in the wastewater treatment process.

This study describes the preparation of Ni–P–Cr3C2 composite coatings using pulsed electrodeposition, with varying Cr3C2 concentrations (0, 1, 2, 3, 4, and 5 g/L). Subsequently, the Ni–P–Cr3C2 composite coatings are heat-treated at different temperatures (200, 400, and 600 °C) using the characteristic of Cr3C2 oxidizing to Cr2O3 at high temperatures. The Ni–P coatings, Ni–P–Cr3C2 composite coatings, and heat-treated-state Ni–P–Cr3C2 composite coatings are compared and discussed. The results show that the hardness, wear resistance, and corrosion resistance of the composite coatings are optimized when the Cr3C2 content is 3 g/L and the heat-treatment temperature is 400 °C. This is due to the presence of oxides such as Cr2O3 on the surface of the composite coatings after heat treatment at 400 °C. By efficiently enhancing the coating’s densification to the substrate, these oxides raise the composite coating’s resistance to corrosion and wear. The Ni–P–Cr3C2 composite coating in its heat-treated makeup at 400 °C is found to have long-term corrosion resistance in the 3.5 wt % NaCl solution immersion test. This study provides a new idea in the field of corrosion.

In this study, we investigated the corrosion resistance and passive film characteristics of AlCoCrFeNi2.1 high entropy alloy (HEA) and 2205 duplex stainless steel (DSS) when exposed to a simulated oilfield produced fluid. Our findings reveal that AlCoCrFeNi2.1 HEA exhibits a nobler self-corrosion potential (-340 mVSHE) and a lower self-corrosion current density (3.6 μA/cm2), in comparison to 2205 DSS, exhibiting better overall corrosion resistance, albeit with a narrower stable passivation interval. Long-term immersion tests establish that AlCoCrFeNi2.1 HEA primarily experiences overall corrosion, while 2205 DSS mainly undergoes localized corrosion, notably characterized by pitting corrosion. The predominant elements in the passive film on AlCoCrFeNi2.1 HEA are Al (13.4 at.%), supplemented by varying amounts of Fe (2.4 at.%), Cr (4.8 at.%), Ni (2.2 at.%), and Co (1.3 at.%). In contrast, the passive film formed on 2205 DSS consists solely of Fe (7.9 at.%) and Cr (5.0 at.%). The absence of the corrosion-resistant elements Mo and Ni in the passive film of 2205 DSS may account for its inadequate corrosion resistance.

Herein, a novel graphitic carbon nitride@graphene oxide (g-C3N4@GO) composite nanofiller is fabricated based on π–π conjugation between carbon nitride and graphene oxide, and is applied to enhance the anti-corrosion behaviour of waterborne epoxy paints. The prepared hybrid filler is compounded with water-based epoxy resin by mechanical blending, and the composite is prepared using high-pressure spraying. The fabricated coating is evaluated for its anti-corrosion performance via electrochemical impedance spectroscopy and neutral salt spray tests. These tests demonstrate that the g-C3N4@GO composite coating exhibits excellent corrosion resistance.