关键词: 聚合物, 分子量, 驱油, 机械降解, 粘度

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