关键词: 驱油体系, 油藏适应性, 分子聚集体尺寸, 分子聚集体形态, 渗透率极限

Abstract:

For the success of the implement of chemical flooding in Daqing oilfield, the viscosity, molecule coil size and molecular configuration of polymer solution, polymer/surfactant compound system, strong base alkali-surfactant-polymer（ASP） system and weak base ASP system, and the permeability range of the shale core and its influencing factors were studied under the same condition. The results showed that under the same condition, the viscosity and molecule coil size were in a descending order as: polymer/surfactant dual system, polymer solution, weak base ASP system, and strong base ASP system. While for the core permeability limit, the order was: polymer/surfactant dual system, strong base ASP system, polymer solution, and weak base ASP system. The reason was the bigger the molecule coil size was, the higher the core permeability that the oil-displacement systems could get through and the greater the permeability limit would be. But the strong base ASP system could react with the minerals in the cores, which resulted in the blocking of the core pores and the increase of permeability limit. The viscosity and permeability range of four kinds of oil-displacement system decreased with the increase of the shear strength, but the shearing action led to the oriented arrangement of the polymer molecules, the change law of polymer molecules in the oil-displacement system after shearing action was unobvious.

Key words: oil-displacement system, reservoir adaptability, molecular coil size, molecular configuration, permeability limit