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Abstract The passivation and depassivation characteristics of Super 13Cr stainless steel were examined under a range of oxygen partial pressures within a high-temperature (120 ℃) and high-pressure (3 MPa) CO2 atmosphere. We performed comprehensive electrochemical assessments, encompassing open-circuit potential monitoring, electrochemical impedance spectroscopy, and linear polarization resistance analysis, to evaluate the corrosion resistance and passive film stability. The results demonstrate that the addition of low O2 partial pressures enhanced the stability of the passive film, while higher O2 levels led to the loss of the passivation properties of Super 13Cr stainless steel. The study elucidates the pivotal role of oxygen in the corrosion mechanisms affecting Super 13Cr stainless steel, presenting valuable data to enhance for integrity management in severe environmental conditions.

The problem of pipe corrosion in oil and gas field injection wells is prominent， causing serious resource waste and safety hazards in the oil and gas industry， and oxygen corrosion has become one of the main causes of pipe perforation failure.Herein， this article reviewed the research progress on oxygen corrosion of pipes in oil and gas field injection environments in recent years， with a focus on the effects of injection well conditions and injection parameters (such as process conditions， temperature， oxygen content， flow rate， etc.) on oxygen corrosion of metal materials.Meanwhile，the mechanism and protection methods of oxygen corrosion were explored，and the shortcomings in current research were analyzed.Finally，based on the requirements of oil and gas field engineering，suggestions were put forward for future research in this field.

This work proposes an intelligent grey-wolf-optimizer-improved Apriori algorithm (GWO-Apriori) to mine the association rules of hidden dangers in hydrogen pipeline transmission stations. The optimal minimum support and minimum confidence are determined by GWO instead of the time-consuming trial approach. Experiments show that the average support and average confidence of association rules using GWO-Apriori increase by 29.8% and 21.3%, respectively, when compared with traditional Apriori. Overall, 59 ineffective association rules out of the total 105 rules are filtered by GWO, which dramatically improves data mining effectiveness. Moreover, 23 illogical association rules are excluded, and 12 new strong association rules ignored by the traditional Apriori are successfully mined. Compared with the inefficient and labor-intensive manual investigation, the intelligent GWO-Apriori algorithm dramatically improves pertinency and efficiency of hidden danger identification in hydrogen pipeline transmission stations. [ABSTRACT FROM AUTHOR]

The corrosion resistance of pure epoxy resin coatings in oil and gas fields must be enhanced by the addition of filler to meet the demands of the severe service environment, particularly under an environment with high Cl– and CO2 contents. In this work, mica materials with different mesh sizes (400#, 800#, and 1250#) were first modified to enhance compatibility with epoxy resin, and then 35 wt % modified mica was doped into epoxy resin to prepare composite coatings, and the effect of the modified mica mesh on the corrosion resistance of the composite coatings in a high Cl– environment containing CO2 was studied. For these materials, the thermal stabilities of the epoxy resin coatings with modified mica were analyzed using a thermogravimetric analyzer, the service environment was simulated by an autoclave, the electrochemical characteristics were studied using an electrochemical workstation, and the surface characteristics were observed by scanning electron microcopy. The results showed that mica was improved by modification with a silane coupling agent, and that with an increase in the mesh size, the uniform distribution of the mica, open circuit potential, capacitance arc radius, and adhesion of the composited coating first increased and then decreased, while the self-corrosion current density, water absorption, and diffusion coefficient showed the opposite trend. When the mesh size of the modified mica was 800#, the highest charge transfer resistance (7.404 × 108 Ω cm2), and adhesion (7.26 MPa), and the smallest double electric layer capacitance (6.814 × 10–9 F cm–2), composite coating capacitance (3.866 × 10–10 F cm–2), self-corrosion current density (3.441 × 10–10 A cm–2), final saturated water uptake (2.03%), and diffusion coefficient (5.306 × 107 cm2 s–1) were observed, indicating that the composite coating with the 800# modified mica soaked for 240 h still had the best corrosion resistance. Finally, a corrosion resistance evolution mechanism was proposed for composite coatings containing epoxy resin with different mesh sizes of modified mica. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]