三元复合体系在多孔介质运移过程中变化规律研究

Study on migration change rule of alkali/surfactant/polymer system in porous media

为进一步探索三元复合体系在储层中的运移变化规律,针对大庆油田流体性质和地质特征,以油藏工程、表面活性剂化学和油田化学为理论指导,基于复合体系各组分浓度动态测试结果,开展了三元复合体系黏度、界面张力和驱油效果变化规律实验研究和机理分析。结果表明,三元复合驱过程中,聚合物、表面活性剂以及碱呈现出不同的沿程滞留特征,出现色谱分离现象,表面活性剂浓度下降速率远快于聚合物和碱浓度下降速率,整个驱替过程中超低界面张力和高黏度状态仅能够保持大约1/3的井距长度。超低界面张力对三元复合驱阶段采收率的贡献比有限,有大约60%以上原油不是复合体系在超低界面张力状态下采出的。三元复合驱使用体系只要在保持较低界面张力状态的同时兼顾充分的黏度性能,也可能获得同样良好的驱油效果。

In order to further explore the migration rule of alkali/surfactant/polymer（A/S/P）system in the reservoir, guided by the reservoir engineering, surfactant chemistry and oilfield chemistry, and aimed at the fluid properties and geological characteristics,we conducted the research on change rule of viscosity, IFT tension and displacement effect of A/S/P system, and discussed the relative mechanism based on the dynamic testing result of single component concentration of compound system. The results showed that during the displacement process of A/S/P system, the polymer, surfactant and alkali presented different along-range retention characteristics, the chromatographic separation phenomenon occurred, the decrease rate of surfactant concentration was much higher than that of polymer and alkali, and both the ultra-low interfacial tension and high viscosity could only keep the length of 1/3 well distance. The contribution rate of ultra low tension was limited in the A/S/P flooding; about 60 % oil was not recovered by compound system under the condition of ultra low tension. If the A/S/P system can keep lower IFT and give consideration to proper viscosity, we can acquire the better displacement effect.