低渗透油藏乳化调驱体系适应性实验

Experimental study on the adaptability of emulsion control and flooding system in low permeability reservoirs

低渗透油藏采用常规的注水开发,效果并不理想,乳化调驱技术为低渗透油藏提高采收率提供了新思路。通过室内实验,探究了储层渗透率、体系浓度、注入时机、注入量、注入方式等因素对乳化调驱体系驱油效果的影响,同时结合微观可视化等实验手段明确了乳化调驱体系提高采收率机理。实验结果表明,乳化调驱体系提高采收率的本质是通过改变储层的润湿性,使微观孔隙中的各类残余油得到有效动用;随着油田开发指标逐年变差,乳化体系驱油效果具有小幅提升;相比于笼统段塞注入,采用段塞交替注入的方式驱油效果更好;当储层含水较高时,乳化调驱体系的驱油能力将会受到抑制。总之,对于注水开发效果不佳的低渗透油藏,乳化调驱体系能更好地驱替细小孔隙中的残余油,研究成果为乳化调驱体系的现场应用提供了理论依据。

As the conventional water injection development is not ideal for low permeability reservoirs,the emulsion profile control and flooding technology is adopted for EOR.Through laboratory experiments,the influence of reservoir permeability,system concentration,injection timing,injection volume,injection mode and other factors on the oil recovery effect of emulsified profile control and flooding system is studied,and then the EOR mechanism is clarified by combining microscopic visualization and other experimental means.The experimental results show that the essence of EOR is to change the wettability of the reservoir,so that different kinds of residual oil in the microscopic pores can be produced.With the decrease of reservoir permeability,the oil recovery effect has a slight improvement.Compared with general slug injection,the experimental group with alternate slug injection has better oil recovery effect.However,when the water content is high,the oil recovery ability will be inhibited.In conclusion,for low-permeability reservoirs with poor water injection development effect,the emulsion profile control and flooding system can better recover residual oil in fine pores,and the research results provide a theoretical basis for field application of the emulsion profile control and flooding system.