渗透率及压力对低渗油藏CO2驱油效率的影响

郭平 黄宇 李向良

1．西南石油大学油气藏地质及开发工程国家重点实验室，四川 成都 610500 中国石化胜利油田分公司地质科学研究院，山东 东营 257000

State Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering, Southwest Petroleum University, Chengdu 610500, China Geological Research Institute, Shengli Oilfield Company, SINOPEC, Dongying 257000, China

注CO2开发油气田是一种有效提高油气采收率的技术手段，但由于CO2驱油成本较高，分析储层是否适合注CO2，其驱油方式的可行性研究至关重要。地层渗透率和压力保持水平对CO2驱油效率影响较大，因此，通过室内长岩心物理模拟实验，研究了在不同渗透率和压力保持水平条件下CO2驱油效率、驱替压差及气体突破时机的变化情况。结果表明：驱替过程中驱替压差随渗透率的降低而增大，驱油效率和气体突破时间也都随渗透率降低而增大；随压力保持水平升高，CO2突破时间越长，驱油效率也越高。

CO2 injection in the development of oil and gas field is an effective technology for EOR. It is essential to analyze the feasibility of CO2 injection for the reservoir due to high cost of CO2 injection. Previous study has showed that the permeability and pressure of reservoir have great influence on CO2 displacement efficiency. Thus, long core tests have been done to study how CO2 displacement efficiency, pressure difference and breakthrough time vary with permeability and pressure of reservoir. The result shows that pressure difference goes up with permeability decreasing within a certain permeability range, CO2 displacement efficiency and breakthrough time is inversely directly proportional to permeability. As pressure becomes high, both CO2 breakthrough time and displacement efficiency are increasing.

10.6056/dkyqt201306022