Abstract: The feasible research shows that miscible CO₂ flooding can be carried out economically and effectively in the complex small fault blocks.Under the conditions of keeping the minimum miscible pressure by injecting water, a pilot test for miscible CO₂ flooding started in Fu 14 fault block of Jiangsu Oilfield at the end of 1998.After six periods of water-alternating-gas (WAG) testing,the ratio of water and gas volume under reservoir condition is from 0.86:1 up to 2:1.The producing wells have obvious effect of oil increasing,and a new enriched oil zone is formed in the water flooded reservoir.The oil production rate increases from 0.5% to 1.2%,and the water cut declines from 93.5% to 63.4%.Up to now,the area of CO₂ flooding zone has increased by 4%,and the utilization rate of CO₂ for oil recovery is 1240m³ per one ton oil.The test is continuing.The success of the miscible CO₂ flooding in Fu 14 block offers an important basis for enhancing oil recovery in complex small oilfields.

Key words: CO₂, miscible drive, water alternating gas (WAG) injection, recovery, complex small fault block, Jiangsu Oilfield

摘要： 对江苏油田富14断块进行的可行性研究结果表明,复杂小断块油藏可以进行经济有效的CO₂混相驱。江苏油田富14断块在保持最低混相压力的状态下,于1998年末开始进行了CO₂—水交替(WAG)的注入试验。进行了6周期的注入试验后,水气比由0.86:1升至2:1。油井见到了明显的增油降水效果,水驱后油层中形成了新的含油富集带。试验区采油速度由0.5%升至1.2%,综合含水率由93.5%降至63.4%。到目前为止,CO₂波及区采收率已提高4%,CO₂利用率为1240m³/t(油)。试验仍在继续进行。富14断块CO₂混相驱的成功为提高复杂小断块油藏采收率和丰富国内三次采油技术提供了重要的依据。

关键词: CO₂, 混相驱, 水气交替注入, 采收率, 复杂小断块, 江苏油田