大庆油田四次采油凝胶颗粒+聚合物驱技术研究

针对大庆油田聚合物驱后油层优势渗流通道发育,层间、层内、平面三大矛盾加剧,而高浓度聚合物驱用量大,但经济效益较差的问题,自主研发PPG凝胶颗粒,攻关了PPG+聚合物驱技术,实现了“堵、调、驱”有机结合。采用仪器检测和物理模拟实验等方法,分析PPG+聚合物体系渗流特性、驱油效果,筛选出最佳体系配方及注入方式。研究结果表明:调驱型PPG具备增黏特性,调驱型PPG+聚合物体系90 d黏度保留率高达78.9%;与单纯聚合物溶液相比,PPG+聚合物体系黏弹性显著增加,具备更强的调堵能力;聚合物驱后先注入0.05倍孔隙体积封堵型PPG+聚合物体系,再注入0.70倍孔隙体积调驱型PPG+聚合物体系可取得最佳驱油效果,可节省24%聚合物用量。预测研究区采用PPG+聚合物驱后可提高采收率8.57个百分点。该研究可为大庆油田四次采油阶段持续高效开发提供技术支撑。

Research on Gel Particles + Polymer Flooding Technology for Quaternary Oil Recovery in Daqing Oilfield

After polymer flooding in Daqing Oilfield, the dominate seepage channels were very developed in the reservoir, the three major interferences, that is interlayer interference, inner layer interference and plane interference, intensified, the consumption of high-concentration polymer for flooding grew, and the economic benefits declined. In view of these problems, PPG gel particles were developed independently, and the PPG+polymer flooding technology were established, realizing the organic combination of "plugging, adjusting and flooding". Through experimental methods such as instrument detection and physical simulation, etc., the seepage characteristics and oil displacement effect of PPG+polymer system were analyzed, and the optimal system formula and injection pattern were screened. The research results show that: PPG for flooding control can increase viscosity, and viscosity retention rate of PPG+polymer system for flooding is as high as 78.9% after 90 days. Compared with pure polymer solution, the viscoelasticity of PPG+polymer system increases significantly, and the system has stronger plugging control properties. The optimal flooding effect can be achieved by firstly injecting PPG+polymer for plugging control with 0.05 PV and then injecting PPG+polymer for flooding control with 0.70 PV, which can save polymer consumption by 24%. After implementing PPG+polymer system for flooding control to the blocks for research and prediction, the recovery rate has increased by 8.57 percentage points. The research can provide technical support for continuous and efficient development of quaternary oil recovery stage.