利用CO2气驱开采复杂断块油藏“阁楼油”

复杂断块油藏进入高含水后期，位于构造高部位的“阁楼油”难以经济而有效地开发。苏北盆地拥有丰富的天然CO2气源，采用槽船运输、井口增压和高压升温等技术，在溱潼凹陷储家楼油田开展CO2气驱试验。通过数值模拟优选出CO2气驱方案，并于2000年10月开始矿场试验，已注入CO2气132．06万m^3，占油藏孔隙体积的1.59％，已增产原油2545t．综合含水率降低6％，每立方米CO2气换油0．001927t，提高油藏采收率1.07％，效果显著。试验取得了一批宝贵的资料，对CO2气驱的开采过程及生产动态特点有了新的认识。试验结果表明，选择油藏低部位井注入CO2气驱替水驱剩余油，能在油藏高部位形成新的油气富集带，机理清楚，工艺相对简单，见效快，是一种值得推广的复杂断块油藏三次采油方式。图3表3参12

Production of attic oil in complex fault block reservoir by CO2 gas drive

In the late high water cut stage of complex fault block reservoir, the attic oil at the high point of the structure is difficult to be developed economically and effectively. With the abundant natural source of CO2 gas and the techniques of tank boat transportation, wellhead supercharging and high-pressure temperature rise, CO2 gas drive has been conducted in the Chujialou Oilfield, Qintong depression, north Jiangsu Basin. The optimal project of CO2 gas drive is selected by numerical simulation, and the field test began in Oct., 2000. CO2 gas of 132.06×104m3, 1.59 percent of oil reservoir pore volume, has been injected into the reservoir. The oil increment is 2545t, and the water cut is decreased by an average of 6%. The oil draining factor of CO2 is 0.001 927t/m3. Recovery factor has increased by 1.07%. The field test reveals that CO2 injection from well at the lower point of the reservoir can drive the water drive remaining oil and accumulate hydrocarbon at the high point of the reservoir. Meanwhile, more test information about producing process and producing characteristics of CO2 gas drive has been gained. The test results show that production of attic oil in complex fault block reservoir by CO2 gas drive has clear mechanism, relatively simple technique and quick effectiveness. And provides a effective way for tertiary oil recovery of complex fault block reservoir.