弱碱三元复合驱动态特征及其对驱油效果影响

DYNAMIC PERFORMANCE OF ASP FLOODING WITH WEAK BASE AND ITS EFFECT ON OIL DISPLACEMENT

弱碱三元复合体系在油藏多孔介质内结垢不仅会增大流动阻力、减少吸液量，而且会影响油水井生产动态特征，进而影响复合驱增油效果。依据复合驱提高采收率原理，通过分析油水井生产和测试资料，归纳和总结了弱碱三元复合驱动态反映特征。结果表明，成垢作用是造成注入压力升高、吸液量下降、吸液和产液剖面变化的主要原因。在复合驱初期，成垢作用可以改善吸液剖面、扩大波及体积，但中后期它却是加快“吸液剖面反转”的主要因素。分析研究还发现，成垢作用可以改善油井产液剖面、增加中低渗透层剩余油动用程度。

Scaling of the ASP-system in reservoirs with porous medium not only can increase flow resistance and decrease fluid entry rate, but also can influence production performance of producers and injectors, and then impact oil production increase. Based on principle of ASP-flooding, this paper illustrates dynamic characteristics of ASP-flooding with weak base through analysis on production and logging data from producers and injectors. Results indicate that scaling action is the main cause for injection pressure increase, fluid entry rate decrease, and changes of fluid entry and fluid production profiles. In earlier stage, the scaling action can improve fluid entry profile and enlarge swept volume, but it is the main cause to speed up “reversion of the fluid entry profile” in middle and later stages. Analysis also shows that scaling can improve fluid production profile of producers, increase producing degree of remaining oil in medium-low permeability reservoirs