Deng Xu, Fu Meilong, Li Jie, Hu Jiani, Li Guojun, Meng Fankun
Hubei Provincial Key Laboratory of Oil and Gas Drilling and Production Engineering, School of Petroleum Engineering, Yangtze University, Wuhan 430100, China.
Shaanxi Yanchang Petroleum Fengyuan Co., Ltd., Yan'an 716000, China.
ACS Omega. 2024 Feb 12;9(8):9655-9665. doi: 10.1021/acsomega.3c09718. eCollection 2024 Feb 27.
Carbon dioxide flooding can accelerate the development of low-permeability reservoirs of the Kexia group in the K region of the T oil field, thus resolving the issue of inadequate water drive effects. This study was focused on the well group 80513 in the K region, and based on the reservoir and fluid parameters, a simulation model of water-sensitive post-CO flooding was constructed to refine the gas injection strategy gradually. The injection rate of the continuous gas injection stage was preferred based on the degree of recovery. Multiindicator and multifactor injection and extraction schemes were established to optimize and analyze the key controlling factors, including the gas injection rate, gas injection period, gas-to-water ratio, and bottom-hole flow pressure, in the carbon dioxide gas-to-water alternation process. Recovery efficiency, oil exchange rate, formation pressure, and carbon dioxide storage rate were used as indicators. After 5 years of continuous CO flooding, the results indicated that switching to CO gas-water alternating flooding was more appropriate for the target block's environment. The best development plan was achieved when the gas injection rates were 1.0 and 1.25 × 10 m·d for continuous gas injection and CO gas-water alternating flooding, respectively, with a gas-water ratio of 1:1, a gas injection cycle of 90 days, and a bottom-hole flow pressure of 25 MPa in the production wells. A comparison between the results revealed that the formation pressure and oil recovery efficiency of this well group significantly increased upon CO flooding, and the parameter optimization results were well suited for controlling the gas flurry, offering a versatile model for future development of the block.
二氧化碳驱油可加快T油田K区块克下组低渗透油藏的开发进程，从而解决水驱效果不佳的问题。本研究聚焦于K区块的80513井组，基于油藏和流体参数，构建了二氧化碳驱后水敏模拟模型，逐步优化注气策略。根据采收程度优选连续注气阶段的注入速度。建立了多指标、多因素的注采方案，以优化和分析二氧化碳气水交替过程中的关键控制因素，包括注气速度、注气周期、气水比和井底流压。采收率、换油率、地层压力和二氧化碳封存率用作指标。连续二氧化碳驱5年后，结果表明，转二氧化碳气水交替驱更适合目标区块的环境。连续注气和二氧化碳气水交替驱的注气速度分别为1.0和1.25×10 m·d、气水比为1:1、注气周期为90天、生产井井底流压为25 MPa时，实现了最佳开发方案。结果对比表明，该井组经二氧化碳驱后地层压力和原油采收率显著提高，参数优化结果非常适合控制气窜，为该区块未来开发提供了通用模型。
