Abstract: By using polymers having different molecular weight and cores with different pore size taken from reservoirs in Daqing Oil Field, many core floods have been performed. The behaviors of both solution and propagation in porous media, such as viscosity of polymer solution, resistance and residual resistance factor, incremental oil recovery and mechanical degradation, have been studied as a factor of molecular weight. The injectivity has been studied as a mutual factor of pore size of core and molecular weight. The results show that all those parameters in terms of viscosity of polymer solution, resistance and residual resistance factor, incremental oil recovery and mechanical degradation increase as molecular weight increases. The remaining viscosity of the polymer solution is higher though the polymer with higher molecular weight has bigger viscosity loss caused by mechanical degradation under conditions of Daqing Oil Field. The results also show that no plugging occur in a core when the mid-value of pore radius is over 5 times of the gyration-radius of molecules in the polymer solution. Field results of polymer flooding performed in similar geological and operational conditions indicate that the polymer flooding with higher molecular weight has better response and the polymer produced from producers has higher remaining viscosity and molecular weight than those with lower molecular weight.

Key words: polymer, molecular weight, flooding, mechanical degradation viscosity

摘要： 采用不同分子量的聚合物和不同孔隙大小的岩心进行室内驱油模拟实验,研究了聚合物分子量对聚合物溶液粘度、 阻力系数和残余阻力系数、采收率以及机械降解的影响.研究了油层孔隙结构参数与分子量的相互关系对聚合物注入性 能的影响.结果表明,聚合物分子量愈大,阻力系数、残余阻力系数、采收率和机械降解愈大;但在大庆油田的实际条件下, 剩余粘度大.岩心孔隙半径中值与聚合物分子在水溶液中的均方回旋半径比大于5时不会发生油层堵塞.相近地质条件. 不同分子量,相同操作条件下的矿场聚合物驱结果表明:高分子量的聚合物驱效果好于低分子量的聚合物驱效果,采油井 产出的聚合物分子量大,保留粘度高.

关键词: 聚合物, 分子量, 驱油, 机械降解, 粘度