孤岛油田特高含水期提高采收率技术措施及效果

EOR method and effect at extra high water cut stage in Gudao Oilfield

孤岛油田进入特高含水期后,面临产量递减大、含水上升快和剩余油挖潜难度大等难题,通过应用化学驱和稠油热采技术,使油田采收率大幅度提高,形成了砂岩稠油油藏长期高效开发的技术系列。针对二类油藏油层发育差、原油粘度高的特点,通过深化储层认识、优化注聚合物参数、强化注聚合物全过程动态跟踪治理等措施,单元采收率提高了6%～12%,而且降水增油达到一类油藏效果。针对油水过渡带的稠油油藏,根据其井间剩余油富集、水驱效率低和水侵影响大的特点,实施井网加密、低效水驱转热采和水侵治理等技术,使采收率提高了13.8%。同时,发展了河道砂储层构型和空间剩余油描述技术,配套形成了水平井挖潜提高采收率技术,在后续水驱阶段又提高单元采收率3%～5%,使单元采收率达到55%～60%。

After Gudao Oilfield entered extra high water cut stage,it faces such difficulties as high decline of oil production,quick rising of water cut and difficult recovery of oil remaining. The application of technology of chemical flooding and heavy oil thermal recovery made the recovery efficiency greatly enhanced. Long-term high effective development technology for the sandstone heavy oil reservoir was established. In view of the features of reservoir mal-development and high viscosity of crude oil in type Ⅱ reservoirs,the measures of deepening recognition of reser-voir,optimizing polymer flooding parameter,and enhancing dynamic follow and improvement during the whole process were taken with unit recovery enhanced by 6% to 12% ,and the effect of water decreasing and oil increasing has reached the level of type Ⅰ reservoirs. In the heavy oil reservoirs with oil/water transition zone,according to the features of remaining oil enrichment of inter-well,low efficiency of water flooding and great effect of water invasion,the measures were taken including well pattern thickening,shifting inefficient water flooding into thermal recovery and water intrusion improvement with recovery ratio enhanced by 13.8%. At the same time,river channel sand reservoir configuration and remaining oil description in space were developed and applied for the horizontal well. Unit recovery efficiency was en-hanced by 3% to 5% during subsequent water flooding,aod the unit recovery efficiency is up to 55% ～60%.