裂缝性致密油藏CO_2定容混相驱实验研究及应用

Experimental Study and Application of Carbon Dioxide Constant Volume Miscible-flooding in Fractured-tight Reservoir

针对红河油田长8油藏注水开发过程中主向井裂缝性水淹特征严重、侧向井无水驱受效特征、影响油藏采收率的问题,为实现裂缝性致密油藏有效动用,建立了裂缝、基质双重介质条件下CO_2定容混相驱评价模型,并开展红河油田CO_2定容混相驱室内实验研究,分析了CO_2定容混相驱驱替压力传递规律和驱油效果。结果表明:CO_2定容混相驱利用裂缝通道为基质孔隙增能,能够有效提高CO_2和基质孔隙原油的混相程度,比常规驱替方式提高基质驱油效率0.91%~10.11%。CO_2定容混相驱技术在红河油田应用效果良好,井组累计增油1 089.5 t,能够有效提高裂缝性致密油藏基质原油的动用程度。

In view of the serious water flooding of main direction well, invalid water-driving of lateral well, and finally influencing the reservoir recovery in Honghe Oilfield, the evaluation model of CO2 constant volume miscible displacement is established under the condition of double media of fracture and matrix to achieve effective utilization of fractured tight reservoir in this paper. And experiment study of miscible flooding was carried out in Honghe Oilfield. At the same time, the rules of pressure transfer and oil displacement effect of CO2 constant volume miscible displacement were analyzed. The results show that carbon dioxide constant volume miscible-flooding can effectively improve the mixed phase between the carbon dioxide and matrix porosity of crude oil, increasing the matrix pore with fracture channel. Matrix displacement efficiency was improved by 0.91% -10. 11%, compared with the conventional flooding method. Carbon dioxide constant volume miscible-flooding technique has a good application effect in Honghe Oilfield with group total increasing-oil effect about 1089.5t. Carbon dioxide constant volume miscible-flooding can effectively enhance producing degree of matrix of crude oil in fractured-tight reservoir.