低渗透油藏空气泡沫复合驱油室内实验研究

Experimental study on air-foam flooding for low-permeability reservoirs

针对低渗透油藏注水开发过程中存在着油井含水上升快,污水处理难度大,产量下降快,油藏采出程度低,生产成本高等问题,对低渗透油藏空气泡沫复合驱提高采收率技术的可行性进行了探讨。通过室内实验对泡沫剂的发泡性、稳泡性、泡沫与原油界面张力性能和稳泡剂的稳泡性能进行评价,优选出最佳泡沫配方;通过驱油实验分别从注入量、气液比、注入压力等方面对低渗透油藏空气泡沫复合驱油工艺参数进行研究。实验结果表明,当气液比在1∶1～3∶1范围变化时,采收率随气液比增加而升高,随着注入泡沫液量的增加而增大,当注入量增加到0.4PV时增加不明显;同时当气液比为3∶1时,采收率随着注入压力增加而增大,直至趋于平稳。因此,空气泡沫复合驱是一种很有前景的提高低渗透油藏采收率方法。

This paper discusses the feasibility of air-foam flooding EOR technology for low permeability reservoirs aiming at the problems occurred during water flooding process such as sharp increasing of water cut,the difficulty to treat produced-water,fast production decline,low degree of reserve recovery,and high production cost. The optimum foam formula is selected through laboratory experiment on the foaminess of frother,the stability of foam,and the interfacial tension between foam and oil. The process parameters of air-foam flooding for low permeability reservoirs have been studied through oil displacement test in respects of injection rate,gas fluid ratio and injection pressure. The experiment result shows that when gas liquid ratio is between 1∶1 and 3∶1,the recovery ratio increases with gas fluid ratio and the amount of injected foam liquid,but the increasing is not obvious when the injected amount increases to 0.4 PV; when the gas liquid ratio is 3∶1,the recovery ratio increases with the increasing of injection pressure. Therefore air-foam combination flooding is a promising recovery technique for low permeability reservoirs.