任丘雾迷山组油藏目前开采方式调整的数值模拟研究

华北油田任丘雾迷山组油藏是我国已发现的最大的裂缝性潜山油藏，经过２１年的开发，已进入开发后期。１９９４年以来，该油藏实行了全面停注降压开采，获得较好的开发效果。由于该油藏目前压降已接近允许的压降界限值，需要对下一步开采方式进行调整。应用数值模拟方法，对该油藏８种继续降压而产液量不同方案和４种恢复注水保持不同压力水平方案、６种周期注水方案的开采效果进行了模拟研究和预测、对比。根据模拟结果认为，在油藏压降未达到极限压降值之前，继续降压开采仍可发挥油藏弹性能量，但提液或降液开采都会使开发效果变差；在压降达到极限压降值时，应补充注水保持较低压力水平开采，压力水平越低效果越好，但同样不宜提液或降液开采；对于综合含水已达８７．９％的该油藏而言，周期注水方式开采提高采收率的效果不明显。图３参１（郭海莉摘

Numerical simulation study of development adjustment for Wumishan reservoir, Renqiu oil field by pressure drop.

Wumishan reservoir, Renqiu oil field, is the largest fractured buried hill reservoir in China, so far discovered. After 21 years of development, it is now in its later development stage. This reservoir has been developed by overall stop injection and pressure drop technique since 1994, and better results have been obtained. The next development technique should be adjusted further because the reservoir pressure drop now approaches its limit allowed. Eight programs producing at different rate under continuous pressure drop, 4 programs with restoring injection to maintain reservoir pressure at different levels, and 6 programs with cyclic injection are studied by numerical simulation for their development results, being predicted and compared. It is recognized by simulation results that before the reservoir pressure drop reaches its limit, production by pressure drop continuously can utilize the clastic energy further, while the development result will be inferior by production with increasing or decreasing production rate; water injection to maintain reservoir pressure at a low level is required and development results will be better for a lower reservoir pressure level, and increasing or decreasing production rate should be avoided also; for a water cut reaches 87.9% cyclic injection has no significant effect on recovery enhancement.