低渗油藏自乳化驱油体系研制与性能研究

Development and performance evaluation of self-emulsification flooding system for low permeability reservoirs

低渗透油气藏存在着储层物性差、小孔喉、毛管力大以及强贾敏效应,常规水驱工艺的采收率较低。基于此,本文提出一种快速自乳化原油的增效驱油方法,合成出一种具有水溶性的表面活性剂DZRH,将其两性离子表面活性剂混合,利用分子间的协同增效作用,于室内配制出适用于低渗油藏的3000mg·L^(-1)的DZRH/LHSB自乳化表面活性剂复配体系。通过低渗岩芯物理模拟驱替实验表征其驱油性能,实验结果表明,该体系可快速自乳化原油形成平均液滴粒径约为0.2μm的乳状液,并且粒径分布较为均匀;该驱油体系可在较大的浓度和复配摩尔比范围内维持极低的油水界面张力,水溶性良好。该自乳化驱油体系可在水驱后有效启动剩余油,进一步提高原油采收率12.89%~14.56%,可为低渗透油藏提高采收率的研究提供技术支撑。

Low permeability reservoir has poor reservoir physical property,small pore throat,large capillary force and strong jamin effect,so the recovery efficiency of conventional water flooding technology is low.Based on this,this paper proposes a rapid and efficient flooding method for self-emulsification crude oil.A water-soluble surfactant DZRH is synthesized,and the zionic surfactant is mixed.A DZRH/LHSB self-emulsification surfactant compound system of 3000mg·L^(-1) for low permeability reservoir was prepared in laboratory.The oil displacement performance of the system was characterized by physical simulation displacement experiments of low permeability core,The experimental results showed that the system can quickly self-emulsification crude oil into emulsions with an average droplet size of about O.2μm,and the particle size distribution is relatively uniform.The oil displacement system can maintain very low interfacial tension of oil and water in the range of large concentration and compound molar ratio,and the water solubility is good.The self-emulsification oil displacement system can effectively start the residual oil after water flooding,and further improve the crude oil recovery by 12.89%~14.56%,which can provide technical support for the research of enhanced oil recovery in low permeability reservoir.