水平井置胶成坝深部液流转向物理模拟

Physical modeling of in-depth fluid diversion by "gel dam" placed with horizontal well

针对正韵律厚油层注水开发过程中注入水沿底部高渗层无效循环问题,提出水平井置胶成坝深部液流转向技术思路,即在正韵律厚油层底部的高渗透、强水洗油层部位钻(侧钻)水平井,通过水平井注胶,形成"胶坝",使注入水转向驱替上部低渗透层,扩大水驱波及体积,提高上部低渗透层储量的动用程度,从而起到挖潜和提高水驱采收率的作用。应用二维可视非均质填砂模型水驱油物理模拟实验,研究水平井胶坝对改善正韵律厚油层水驱效果的影响。实验结果表明,在高渗透油层建"挡水坝",增油降水效果明显,1个"挡水坝"模型,能够提高原油采出程度17.6%;2个"挡水坝"模型,能够提高原油采出程度27.3%。水平井置胶成坝深部液流转向技术突破了堵剂深部放置的技术瓶颈,能大幅度提高正韵律厚油层水驱波及程度。

In view of the ineffective cycling issue of injected water through the high permeability zones during water flooding process in positive rhythm reservoirs,the ＂gel dam＂ in-depth fluid diversion technique is proposed.The technique involves the injection of gel by horizontal or sidetracking wells drilled in the more permeable and strongly swept zones of thick positive rhythm reservoirs.The injected water then will bypass the ＂gel dams＂ and be diverted into the upper unswept or poorly swept low permeability zones.As a result,the swept efficiency and oil recovery of the upper low permeability zones can be both increased.A 2D visible sandpack physical model was set up,and a video camera was used to visualize ＂gel dam＂ in-depth fluid diversion effects.The results of the experiments indicated that,with one or two ＂gel dams＂,the sweep volume and ultimate oil recovery were both increased greatly,and the water cut ascending velocity was decreased.Compared with the physical model without ＂gel dam＂,the ultimate oil recoveries of those with one or two ＂gel dams＂ increased by 17.6% and 27.3%,respectively.By ＂gel dam＂ in-depth fluid diversion technique,the difficulties in the in-depth placement of plugging agents will be solved,and the swept efficiency of positive rhythm reservoir can be increased significantly.