聚合物驱后地层残留聚合物再利用技术研究

Studies on the reutilization techniques of the residual polymer in formation after polymer flooding

聚合物驱转水驱后含水率上升快,同时地下又残留大量聚合物,以溶液溶解、吸附、捕集的形式存在.为了解决这个问题,提出了向地层注入再利用剂将地层残留聚合物再利用,形成弱冻胶或(和)絮凝体,封堵高渗透层,控制水的窜流,通过提高波及系数提高原油采收率.残留聚合物再利用技术包括固定技术和絮凝技术.研究证实,絮凝技术主要利用地下低质量浓度的聚合物,固定技术主要利用地下高质量浓度的聚合物.絮凝剂可用固体颗粒,优化的絮凝剂为稳定化钠土;固定剂可用聚合物交联剂,优化的固定剂由地层温度和矿化度决定,对孤岛油田地层条件优选为醋酸铬与乳酸铬的混合物(YG107).该技术在双河油田和孤岛油田矿场试验取得了很好效果,是聚合物驱后提高采收率首要的接替技术.

The water-cut quickly increases in the water flooding after polymer flooding,and at the same time,a quantity of residual polymer remains in formation in the forms of solution,adsorption and entrapment.For solving the problem of the water-cut quickly increasing,the reutilization techniques of the residual polymer in formation are put forward.By injecting reutilization agent,the residual polymer forms weak gel or(and)flocculate in formation,and they can shutoff high-permeability formation and increases the sweep efficiency of the water flooding.The reutilization techniques of residual polymer include fixation and flocculation.The flocculation technique mainly makes use of low mass concentration of residual polymer and the fixation technique mainly makes use of high mass concentration of residual polymer.Solid particle can be used as flocculating agent and the excellent flocculating agent is stabilizing clay.Polymer cross-linking agent can be used as fixing agent and the excellent fixing agent is decided by formation temperature and salinity,and for the formation condition of Gudao Oilfield,the mixture of chromium acetate with chromium lactate is excellent fixing agent.The pilot test results in Shuanghe and Gudao Oilfields show that the residual polymer reutilization technique should be the first selected EOR technique after polymer flooding.