低界面张力氮气泡沫驱提高采收率实验

EORE xperiments of N₂ Foam Flooding with Low Interfacial Tension

刘勇 唐善法 薛汶举

LIU Yong TANG Shanfa XUE Wenju

通过泡沫综合性能评价及油水界面张力测试，优选了低界面张力氮气泡沫体系，优化了注入参数，对比了泡沫驱、聚合物驱、低交联聚合物驱、聚合物/表面活性剂二元复合驱提高采收率的效果，并模拟现场油田进行了聚合物驱和聚合物/表面活性剂二元复合驱后低界面张力氮气泡沫驱实验。优选的低界面张力氮气泡沫体系配 方为：0.3% 复合起泡剂（椰油酰胺甜菜碱DK+烷基醇胺PM（5∶1））+ 0.1% 稳泡剂PA（天然高分子衍生物），该体系与原油间的界面张力为0.0531mN/m，泡沫综合指数Fq 为10312.5 mL·min；最佳气液比为1.5∶1，注入方式为共混注入，注入速度72mL/h。驱油实验表明，该低界面张力氮气泡沫驱体系的驱油效果（提高采收率11 .4%）优于表面活性剂/聚合物（SP）二元复合驱（提高采收率9.61%）、低交联聚合物驱（提高采收率7.13%）、聚合物驱（提高采收率6.37%）；在模拟该油田水驱（采出程度36%）、聚合物驱（采出程度45%）及二元复合驱（采出程度47%）后，低界面张力氮气泡沫驱仍可提高采收率10.8%。图2 表6 参11

Through the measurement of foam comprehensive performance and oil-water interfacial tension ，N2 foam flooding with low interfacial tension was obtained and the injection parameter was optimized ；furtherly ，the EOR effect of foam flooding，polymer flooding，low crosslinked polymer flooding and SP flooding was compared ，and the low interfacial tension nitrogen foam flooding experiments were conducted after simulated oilfield polymer flooding and SP flooding.The recipe of the optimized low interfacial tension strvng foam system was as follows ，0.3% complex foaming agent（cocamidopropylbetaine（DK）+ alkanolamine （PM）（5∶1））and 0.1% natural polymer derivative （PA），and the interfacial tension between the system and the crude oil was of 0.0531mN/m，the foam comprehensive performance Fq was of 10312.5 mL·min，the best injection-gas-liquid ratio was 1.5∶1，the injection ways was that solution and nitrogen was injected at the same time，and the injection velocity was 72mL/h. The oil displacement experiments showed the enhanced oil recovery （11 .4%）of the low interfacial tension N2 foam flooding system was better than that of SP binary compound flooding（9.61% ），that of the low cross-linking polymer flooding（7.13% ）and that of polymer flooding（6.37%）. Moreover ，the oil recovery was still enhanced by 10.8% through the low interfacial tension N2 foam flooding after simulated oilfield completing water flooding（oil recovery 36%），polymer flooding（oil recovery 45%）and binary compound flooding （oil recovery 47%）