The corrosion behavior of P110 casing steel in simulated concrete liquid and simulated annulus fluid was investigated to reveal the corrosion pattern and protective properties of corrosion products in the two environments. Potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), Mott–Schottky tests, and electrochemical noise (EN) tests were used to study the corrosion behavior of P110 casing steel in simulated concrete liquid and simulated annulus fluid saturated with CO₂. Scanning electron microscopy (SEM) combined with Energy-Dispersive Spectrometer (EDS) mapping was used to characterize the corrosion morphology and elemental distribution of P110 casing steel. The results show that the corrosion resistance of P110 casing steel deteriorates with the increasing immersion days in the simulated annulus fluid, the impedance decreases gradually, and the corrosion-product film shows a loose and porous structure. In the simulated concrete liquid, under the condition of containing a low concentration of Cl⁻, the protection of the corrosion products gradually increases with the extension of immersion days. With the increasing concentration of Cl⁻ and the extension of immersion days, the electrochemical noise resistance and charge transfer resistance of P110 steel decrease gradually, and the protective property of the corrosion-product film decreases, which is capable of forming steady pitting corrosion.

Aiming at low permeability, high water content light reservoir with a recovery rate higher than 20%, an improved air injection enhanced heat flooding technology is applied by combining the combustion reaction flow and flue gas flooding mechanism. The method involves the injection of air into the reservoir, which reacts with the crude oil at temperatures ranging from 220 to 300 °C. This reaction consumes part of the oil, enabling effective evaporation and flow of the remaining oil. This process combines combustion reaction flow with flue gas flooding, using high-temperature oxidation reactions to mobilize residual oil. Experimental results from combustion tube tests demonstrate stable reaction fronts, peak temperatures reaching up to 550 °C, and a significant increase in recovery rates, reaching 73.8% in some cases. Field applications of this technology require maintaining high air flux and burning rates in low-permeability zones to ensure effective heat-driven evaporation. The geological model of the well group shows that the recovery factor of the target block can be increased by more than 20% by air injection based on the water drive recovery factor of 28%–30%. The oil exchange ratio can be less than 4000 sm3/m3 by optimizing the air injection rate and oxygen content. The research results provide technical feasibility for heat flooding to significantly improve oil flow and recovery in low-permeability light oil reservoirs.

氧化镓(Ga₂O₃)纳米材料在紫外透明电极、高温气体传感器、日盲紫外探测器和功率器件等领域具有巨大的应用潜力, 而实现高结晶质量和尺寸形貌可控的Ga₂O₃纳米材料是关键. 本文通过水热法制备了不同尺寸的羟基氧化镓(GaOOH)纳米棒、纳米棒束和纺锤体, 经后期高温煅烧均成功转变为高质量单晶β-Ga₂O₃纳米材料并较好地保留了原始GaOOH的形态特征. 利用X射线衍射(XRD)、拉曼散射光谱(Raman)和场发射扫描电子显微镜(FE-SEM)等表征手段系统研究了前驱液的pH值大小和阴离子表面活性剂浓度对GaOOH和β-Ga₂O₃纳米材料晶体结构和表面形貌的影响, 并深入探讨了不同条件下GaOOH纳米材料的生长机制. 此外, 室温光致发光谱(PL)测试发现不同形貌的β-Ga₂O₃纳米材料均展现出典型的蓝绿色发射峰和尖锐的红光发射峰, 与纳米材料中本征缺陷的存在密切相关. 上述研究结果为未来实现高质量β-Ga₂O₃纳米材料的可控制备提供了有益参考.

Deep oil reservoirs, characterized by high temperature and high pressure, are conducive for enhancing the miscibility between gas and crude oil, thereby improving oil recovery. This paper focuses on a high-water-cut deep oilfield in Xinjiang and experimentally investigates the potential and influencing factors of gas flooding for enhancing oil recovery. These factors include permeability, type of injection gas, injection rate, injection pressure, and injection method. Based on geological characteristics, three types of experimental long-core samples: high permeability, medium permeability, and low permeability, were selected. Hydrocarbon gas injection experiments were conducted after water flooding at conditions of 112 °C and 55 MPa to evaluate displacement effects. Results indicated that high permeability cores exhibited the best displacement, with gas flooding recovery rates 39.53% higher than those from water flooding. Low permeability cores demonstrated a 35.46% increase in oil recovery, significantly surpassing the 29.31% increase observed in medium permeability layers. Among the four flooding media tested, CO2 was found to have the best displacement effect, increasing oil recovery by 33.22%, followed by hydrocarbon gas and associated gas, while N2 was the least effective (7.27%). Higher injection pressures (55 MPa) notably improved the final recovery degree, resulting in a 41.40% increase. Additionally, alternating injections of water and gas enhanced recovery by 13.02% compared to continuous gas injection. A lower injection rate of 0.5 ml/min improved recovery by 7% over 1 ml/min. Therefore, for medium permeability layers under high-water-cut conditions, the optimal gas injection scheme consists of using hydrocarbon gas as the injection medium, with an injection flow of 0.5 ml/min and a pressure of 55 MPa, employing a water–gas alternating injection mode. This study provides valuable experimental and theoretical support for enhancing oil recovery through gas flooding in high-water-cut deep reservoirs.