【作者】 李洪巍；

【导师】 唐伦成；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2003， 硕士

【摘要】 近年来大庆油田开展了大规模三元复合驱矿场试验，取得了比水驱提高石油采收率20％以上的好效果，同时三元复合驱采出液中残留的碱、表面活性剂和聚合物也导致采出液油水乳化严重，使油水分离难度明显加大。 本文系统地研究了大庆油田三元复合驱采出液中残留的碱、表面活性剂和聚合物对三元复合驱采出液乳化强度、油水分离特性、油相体相流变性、水相体相流变性及油水界面性质的影响规律，得出了大庆油田三元复合驱采出液的乳化和稳定机理。 本文中得出的主要研究结论包括： (1)大庆油田三元复合驱采出液中残留的碱、表面活性剂和聚合物导致采出液油水乳化严重，油水乳状液稳定性增强，油水分离难度加大； (2)大庆油田O／W型三元复合驱采出液的乳化机理为：油珠在作用其上的粘性剪切应力的作用下发生破裂，其中采出液中残留的碱和表面活性剂使油水动态界面张力大幅度下降，使油珠抵抗变形的能力下降，容易发生变形和破裂；采出液中残留的聚合物使水相粘度增大，使作用在油珠表面上的粘性剪切应力增大，导致油珠破裂趋势增强； (3)大庆油田O／W型三元复合驱采出液稳定性随其中残留的碱、表面活性剂和聚合物含量增大而增强的主要原因是残留的碱、表面活性剂和聚合物造成三元复合驱采出液油珠粒径减小，乳化强度增大； (4)大庆油田O／W型三元复合驱采出液的稳定机理为： ①碱、表面活性剂和聚合物造成O／W型三元复合驱采出液乳化强度增大油珠粒径减小，使油珠上浮速度和聚结速率下降，同时也使油珠聚结过程中被束缚在油相中的水滴粒径减小，造成O／W型三元复合驱采出液破乳后上层W／O型乳化原油的稳定性增强； ②聚合物对三元复合驱采出液水相的增粘作用使油珠上浮和水膜排液速度降低； ③高碱含量下，碱对油水扩散双电层的压缩作用使油水界面上吸附的原油中的天然界面活性物质、碱与原油中天然物质反应生成的界面活性物质及哈尔滨l_程大学硕十学位论文表面活性剂偏向油相一侧，所产生的空间位阻使0/W型三元复合驱采出液破乳后所形成的W/0型乳化原油中的水滴聚结困难; (5)0/W型三元复合驱采出液的相分离过程可分为油珠上浮、油珠聚结和水滴沉降三个相互平行和互相衔接的子过程; (6)可采用稀释高浓度乳状液制备具有相同初始分散相液滴粒径分布的稀乳状液的方法研究乳状液中各种化学物质和外加物质对乳状液稳定性的影响规律; (7)大庆油田0/W型三元复合驱采出液中残留的阴离子型部分水解聚丙烯酞胺对油珠有显著的絮凝作用，这种作用随聚丙烯酞胺浓度增大而增强，表面活性剂及表面活性剂与碱的协同作用可显著降低聚丙烯酸胺对油珠的絮凝作用。更多还原

【Abstract】 ASP flooding have been widely tested in Daqing Oilfield. While significant decrease of water-cut of produced liquid and increase of oil production have been achieved, residual alkaline, surfactants and polymer in produced liquid have resulted in stable crude oil emulsion, causing great troubles in surface oil-water separation processes.In this work, emulsification and stabilization of o/w ASP flooding produced liquid in Daqing Oilfield were systematically studied on artificial ASP flooding produced liquid and oily water. The influences of alkaline (NaOH), surfactant and polymer (partially hydrolyzed polyacrylamide PAM) on the stability of ASP flooding produced liquid and oily water were tested. Bulk phase rheology and interfacial properties such as interfacial tension, oil droplet Zeta potential and interfacial rheology were tested to reveal the mechanisms of the emulsification and stabilization of ASP flooding produced liquid.Emulsification of o/w ASP flooding produced liquid i.e. breakage of oil droplet is caused by the mechanical shearing force exerted on oil droplets by the surrounding liquid (water). The significant enhancement of the emulsification of chemical flooding produced liquid is mainly caused by the reduction of dynamic oil-water interfacial tension by residual alkaline and surfactant, and the increase of water phase viscosity by residual polymer. Decrease of interfacial tension results in less resistance to oil droplet deformation and thus decrease of energy consumption to break an oil droplet.The enhanced stability of ASP flooding produced crude oil emulsion results mainly from its intensified emulsification by the residual alkaline, surfactant and polymer in it.The stabilization of ASP flooding produced liquid by residual alkaline, surfactant and polymer lies in the enhanced emulsification of produced liquid in which smaller oil droplets are produced, the increase of water phase viscosity by polymer which decreases oil droplet rising velocity and the hindrance of alkaline and surfactant to oil droplet coalescence. Decrease of oil droplet size results inlower o/w ASP flooding produced crude oil emulsion creaming rate and smaller oil droplets in the condense oil droplet layer on top of o/w ASP flooding produced crude oil emulsion, leading to lower oil droplet coalescence rate and smaller water droplets held in oil layer after oil droplet coalescence (tight w/o crude oil emulsion). The increase of water phase viscosity results in slower emulsion creaming, slower draining rate of the water membrane between two approaching oil droplets and thus slower oil droplet coalescence rate in the condense oil droplet layer on top of the o/w crude oil emulsion. In case of high alkaline concentration, alkaline repels the surface-active components on oil-water interface such as indigenous surface-active components in crude oil, the products of chemical reaction between alkaline and indigenous components in crude oil, and the injected surfactant to the oil phase side, resulting in stronger steric hindrance to water droplet coalescence and thus tighter w/o crude oil emulsion on top of o/w chemical flooding produced crude oil emulsion after emulsion creaming and oil droplet coalescence.The phase separation process of o/w chemical flooding produced liquid constitutes of three parallel and successive subprocesses: oil droplet rising (creaming), oil droplet coalescence, and water droplet settling.The influences of indigenous components and injected chemicals on the stabilization of emulsion can be tested by diluting condense emulsion to form dilute emulsions of same droplet size distribution but with different composition.The residual polymer acts to flocculate the oil droplets in ASP flooding produced o/w crude oil emulsion. The flocculating effect of polymer on oil droplets increases with polymer content. The presence of alkaline and surfactant weakens the flocculating effect of polymer on oil droplets.更多还原