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

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