聚合物分子聚集态对液流转向效果影响及其作用机理

Influences of Polymer Molecular Aggregation on Fluid Diversion Effect and Its Mechanism Analysis

对4种调驱剂聚合物纳米球、部分水解聚丙烯酰胺(HPAM)溶液、Cr3+聚合物凝胶和聚合物表面活性剂的黏度、分子线团尺寸、微观聚集态、驱油效果及其液流转向效果进行了研究和机理分析。结果表明,浓度相同时,调驱剂的黏度从大到小依次为:聚合物表面活性剂】Cr3+聚合物凝胶】HPAM溶液】聚合物纳米球(约2 m Pa·s)。水驱至含水40%后转注0.38 PV调驱剂,采收~增幅从大到小依次为:Cr3+聚合物凝胶(14.5%)】HPAM溶液(10.2%)】聚合物表面活性剂(6.8%)】聚合物纳米球(-5.1%)。液流转向效果实验结果表明,调驱结束时,Cr3+聚合物凝胶、HPAM溶液、聚合物表面活性剂、聚合物纳米球调驱后的低渗透层采收~增幅分别为:24.7%、16.5%、10.3%、3.1%,低渗透层分流~分别为:20.8%、12.4%、9.7%、3.2%。聚合物分子聚集态是影响黏度及液流转向效果的主要因素。聚合物纳米球、HPAM溶液、Cr3+聚合物凝胶和聚合物表面活性剂的水动力学半径Rh(0.267、0.066、0.079和0.771μm)均小于0.46R(R为岩石孔喉半径),理论上难以形成稳定封堵,其聚集态分别为颗粒状、线网状、局部网状和区域性网状。Cr3+聚合物凝胶在岩石孔喉内的滞留量和流动阻力最大。聚合物表面活性剂黏度较高,但与岩石的孔喉配伍性较差,易在注入端面发生堵塞。

Experiments were conducted to study the viscosity,molecular configuration dimension,molecular aggregation,effect of flooding and fluid diversion of four kinds of flooding agents,and the mechanism was analyzed briefly. The results showed that the flooding agents were arranged according to the viscosity at same concentration in following order:polymeric surfactant>Cr3 +polymer gel>HPAM solution>polymer nanosphere(about 2 m Pa·s). When the water content of water flooding was 40% and then0.38 PV flooding agent was injected,the flooding agents were arranged according to the increase recovery rate in following order:Cr3 +polymer gel(14.5%)>HPAM solution(10.2%)>polymeric surfactant(6.8%)>polymer nanosphere(-5.1%). The results of fluid diversion experiment showed that,at the end of chemical flooding,the increase recovery rate of Cr3 +polymer gel,HPAM solution,polymeric surfactant and polymer nanosphere in low permeability layer was 24.7%,16.5%,10.3% and 3.1%,and the diversion rate of that in low permeability layer was 20.8%,12.4%,9.7% and 3.2% respectively. The molecular aggregation of flooding agent played a major role in its apparent viscosity and the effect of fluid diversion. The hydrodynamic radius(Rh)of polymer nanosphere,HPAM solution,Cr3 +polymer gel and polymeric surfactant was 0.267,0.066,0.079 and 0.771 μm,which were all less than 0.46R(radius of pore throat). It's difficult to form stable block in pore throat theoretically. Among of them,which had granular,wire network,local network and regional network of molecular aggregation respectively,the retention and flow resistance of Cr3+polymer gel was the largest in rock pore throat. Polymeric surfactant had a high apparent viscosity. However,it had a poor compatibility with the pore throat of rock,and it was more likely to block the injection side.