胜利油田普通稠油乳化驱油体系研制及性能评价

Development and Performance Evaluation of Emulsifying Flooding System for Normal Heavy Oil in Shengli Oilfield

针对胜利普通稠油油藏水驱采收率低且热采成本高的问题,乳化降黏驱是提高其采收率、降低生产成本的有效途径。利用微动力乳化实验装置,综合考虑两种表面活性剂TB与AC在不同配比下的乳化能力和降低界面张力能力,构建了两种不同性能的乳化驱油体系:TB(0.3%)和TB+AC(0.3%,质量比3∶2)。通过多重光散射法分析了两种体系和胜利稠油形成乳状液的微观稳定性,然后通过填砂管驱油实验评价了两种乳化体系的驱油性能,并利用玻璃刻蚀模型研究其微观驱油机理。研究结果表明,TB+AC体系具有强乳化能力,与原油形成乳状液的稳定性良好。TB+AC体系可使油水界面张力达到超低数量级(10^(-3)mN/m),TB+AC体系在水驱基础上可提高采收率11.20%。TB+AC体系通过超低界面张力和强乳化性能“拉”残余油,使其发生形变,降低流动阻力和残余油含量;也可进入油膜深处进一步发生乳化作用使油膜扩张破裂来提高采收率。

Aiming at the problems of low water flooding recovery and high thermal recovery cost in Shengli normal heavy oil reservoir,emulsion viscosity reduction flooding is an effective way to improve recovery and reduce production cost.In this paper,considering the emulsifying ability and reducing interfacial tension of two surfactants TB and AC in different ratios,two kinds of emulsion flooding systems with different properties,TB(0.3%)and TB+AC(0.3%,mass ratio of 3:2),were constructed by using micro dynamic emulsification experimental device.The micro stability of the emulsion formed by the two systems and Shengli heavy oil was analyzed by multiple light scattering method.Then,the oil displacement performance of the two emulsifying systems was evaluated by sand-filled tube oil displacement experiment,and the microscopic oil displacement mechanism was studied by glass etching model.The research results showed that the TB+AC system possessed strong emulsification and the obtained emulsion was stable.The TB+AC system could make oil-water interfacial tension decrease to 10^(-3) mN/m.TB+AC system could enhance oil recovery by 11.20%based on water flooding.The system could"pull"the residual oil through ultra-low interfacial tension and strong emulsifying properties to deform it and reduce flow resistance and residual oil content.In addition,the oil film could also be further emulsified to expand and break the film to enhance oil recovery.