低渗透油藏CO₂驱注入时机研究

 Study on injecting time of CO₂ flooding in low permeability reservoir

 钟张起 2 史运芳² 刘鹏程¹ 彭波³ 庄永涛¹

 1．中国地质大学（北京）能源学院，北京 100083 2．中国石化中原油田分公司采油二厂，河南 濮阳 457532 3．中国石化中原油田分公司科技部，河南 濮阳 457001

School of Energy Resources, China University of Geosciences, Beijing 100083, China No.2 Oil Production Plant, Zhongyuan Oilfield Company, SINOPEC, Puyang 457532, China Scientific and Technological Department，Zhongyuan Oilfield Company，SINOPEC, Puyang 457001，China

 根据吉林油田某区块的油藏条件，运用数值模拟软件，研究CO₂不同注入方式下的驱油效果。数模结果显示，与水驱和连续注气方式相比，交替驱能大幅提高原油采收率。衰竭开采后进行气水交替驱时，随着注入时机的推迟，采收率先是快速增加，然后逐渐降低，不过采收率变化幅度较小。注水开发后进行气水交替驱时，随着注入时机的推迟，采收率先是快速降低，然后逐渐增加，采收率降低幅度较大。注水开发后，经过一段时间焖井，再进行气水交替驱，焖井时间与采收率关系比较复杂，最佳焖井时间可以通过数值模拟得到。

 According to the reservoir condition of certain block in Jilin Oilfield, the displacement efficiency in different displacement modes has been studied with numerical simulation software. The result of numerical simulation shows that the gas-alternating-water flooding can significantly enhance oil recovery compared with continuous CO₂ flooding and waterflooding. In the alternate displacement process after depletion, as the injecting time delays longer, the oil recovery first rises rapidly, and then declines gradually, but the amplitude of fluctuation is small. In the alternate displacement process after waterflooding, as the injecting time delays longer, the oil recovery first declines rapidly, and then rises slowly, having an obvious amplitude of fluctuation. After waterflooding, there is a period of well shut-in time, then, the alternate displacement begins. The optimal well shut-in time can be determined by numerical simulation.

10.6056/dkyqt201203018