弱碱型三元复合驱采出液水相流变性及油水分离特性

Research on water phase rheology and oil-water separation features of the produced liquid by alkalescent ASP flooding

针对目前弱碱型三元复合驱采出液油水分离困难的问题,通过测试模拟采出液的水相弹性模量及热沉降后水相含油量、油层上部含水率和脱出水量,考察了模拟三元复合驱采出液中残留的碱、表面活性剂和聚合物对采出液水相流变性及油水分离特性的影响。结果表明,水相弹性模量主要取决于所含聚合物的相对分子质量和含量,并且随聚合物相对分子质量和含量的增加而增大。当表面活性剂含量相同时,采出液在经过90min热沉降后,脱出水量随水相弹性模量的增大明显降低。水相弹性模量可以代替聚合物含量和相对分子质量这2个因素与脱出水量进行关联。碱、表面活性剂和聚合物含量增大,油层上部含水率和水相含油量均呈现变大的趋势,采出液乳化严重、稳定性提高、油水分离困难。弱碱型三元复合驱采出液可采用热化学脱水工艺实现油水分离。

Oil and water is difficult to separate in the produced liquid by alkalescent ASP flooding. Water elastic modulus of simulated produced liquid and oil content of water phase,water content in oil phase and dehydration quantity after thermal subsidence are tested. The effect of alkali, surfactant and polymer remained on the water phase rheology and oil-gas separation features of the produced liquid by alkalescent ASP flooding are simulated. Studies show that water elastic modulus of the alkalescent ASP flooding mainly depends on the molecular weight of polymer and its content, and increases with them. The quantity of dehydration decreases obviously as the water elastic modulus increases after 90 minute thermal subsidence with the same content of surfactant. Effects of the molecular weight of polymer and its content on the quantity of dehydration can be modeled by the effect of the water elastic modulus on the quality of dehydration. When the content of polymer,surfactant and alkali increase,water content above oil layers and oil content in water phase will increase. The stability of crude oil emulsion increases and separating oil from water become more difficult. Thermo chemical dehydration technology may be applied in oil-water separation of the produced liquid during alkalescent ASP flooding.