摘要
吉林油田CO2驱油藏物性差，渗透率差异较大，裂缝相对发育，注入CO2过程中出现气窜，严重影响气驱效果。为此开展CO2泡沫体系研究，扩大气驱波及体积，提高气驱开发效果。室内建立泡沫体系的性能评价手段，优选一种由阴离子表面活性剂与非离子表面活性剂复配而成的CYL泡沫体系，确定现场CYL泡沫体系的最佳加量为0.3%、气液比1:1。物模试验结果表明：裂缝性低渗透岩心中CO2泡沫驱采收率最高53.67%，CO2气驱采收率次之（35.74%），水驱采收率最低（23.42%）。CO2泡沫驱的效果明显好于水驱、CO2驱，现场开展CO2泡沫驱试验，注气压力由措施前的6.0 MPa上升到措施后的8.1 MPa，井组日产油由措施前的7.7 m3增至措施后的10.8 m3，措施效果明显,有效提高气驱开发效果。
Abstract
Jilin oil field reservoir has the characteristics of poor physical property, great permeability contrast and fracture development, so gas channeling take place easily, which can seriously affect the gas flooding efficiency. To solve the problem, a CO2 foam system was developed to expand the gas flooding swept volume, as well as to improve gas flooding efficiency. A performance method for foam system evaluations was established in the lab, the optimum CYL foam system was chosen, composed of anionic surfactant and nonionic surfactant，and the CYL optimum dosage of 0.3% and the gas-liquid ratio of 1:1 was determined. The physical simulated tests showed that in cores with fracture development and low permeability, the oil recovery ratio (ORR)could be achieved the best of 53.67% by CO2 foam flooding, and the ORR of the CO2 gas flooding toke second place(35.74%), while the ORR of the water flooding was the lowest(23.42%). It was sure that the effect of CO2 foam flooding was obviously better than that of water flooding and CO2 gas flooding. In the field application, CO2 foam flooding test made the gas injection pressure increase from 6.0 MPa to 8.1 MPa , as well as the daily oil production of a well group increase from 7.7 m3 to 10.8 m3. The result of the CO2 foam flooding was obvious, and the gas flooding development was improved effectively.
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