聚表体系在低渗透油藏的注入适应性

Injection adaptability of polymer surfactant systems in low permeability reservoirs

定边学庄区延10属于低孔低渗油藏,前期依靠天然能量开采,导致地层能量亏空严重,注水起步较晚,压力无法维持,学庄注水项目区整体压力水平保持较低,其中延10层压力水平保持最低,目前开始中期注水,压力逐步回升,目前压力维持在70%左右;学庄区延10组整体采出程度为13.47%;区块2020年综合含水率81.13%,较开发初期54%有明显提升,延10层从39.2%上升至88.29%,属于高含水率阶段,因此急需采取稳油控水措施。本文主要通过室内实验,验证聚合物在低渗透油藏的封堵调剖堵水能力及适应性研究,并进一步分析聚表体系注入方式变化对采收率的影响,通过岩心X射线扫描驱替实验,对比水驱剩余油和交替注入剩余油的分布,进一步验证了聚表交替提高采收率的机理。

Yan 10 in Xuezhuang district,Dingbian is a low-porosity and low-permeability oil reservoir.In the early stage,it relied on natural energy for exploitation,resulting in a serious formation energy deficit.The water injection started late,and the pressure could not be maintained.The overall pressure level in the Xuezhuang water injection project area remained low.The pressure level of the 10th layer remains the lowest.At present,the medium-term water injection has started,and the pressure has gradually recovered.The current pressure is maintained at about 70%.The overall recovery degree of the Yan 10 group in the Xuezhuang block is 13.47%.The comprehensive water cut in the block in 2020 is 81.13%,which is relatively developed the initial 54% has increased significantly,and the 10th layer has increased from 39.2% to 88.29%,which belongs to the high water cut stage,so it is urgent to take measures to stabilize oil and water.In this paper,laboratory experiments are used to verify the ability and adaptability of polymers for plugging,profile control and water shutoff in low-permeability reservoirs,and further analyze the influence of changes in the injection mode of the polysurface system on the recovery factor.The displacement experiment,comparing the distribution of the remaining oil in water flooding and the alternate injection,further verified the mechanism of alternately increasing oil recovery by clustering.