反韵律油藏泡沫驱提高采收率研究

Enhancing Oil Recovery by Foam Flooding in Inverted Layered Reservoirs

以胜坨油田二区古近系Es2^8（2-4）单元为目标，以精细油藏描述为基础，建立三维地质模型，研究特高含水后期反韵律油藏剩余油分布特征。针对油藏动态非均质性严重、主力层顶部剩余油相对富集及高温高盐等特点，研制了低张力泡沫体系，在油藏温度85℃、地层水矿化度18500mg／L、钙镁离子质量浓度505mg／L条件下，起泡体积202mL，半衰期132min，界面张力3×1^-30mN／m，在发挥泡沫体系选择性封堵油藏高渗条带、扩大驱替波及面积的同时，其高界面活性有效提高了洗油效率，室内填砂模型驱油试验提高采收率25．0％，为反韵律油藏大幅度提高原油采收率提供了技术方法。

Aimed at the reservoir of Es8(2~4)2in Block Sheng 2of Shengtuo Oilfield,a 3-D geological model was established based on fine reservoir description,the characters of remaining oil distribution in inverted layered reservoirs were studied at the late stage of super-high water-cut of the reservoirs.Low interfacial tension foam flooding system was developed to solve the problems of serious heterogeneity,remaining oil being relatively accumulated on the top of main producing strata and high temperature and high salinity.Under conditions of reservoir temperature of 85℃,formation water salinity of 18500mg/L and Ca2+Mg2+content 505mg/L,its foaming volume was 202mL,half-life period was132min,interface tension was 3×10-3 mN/m.The foam system had superiority of shutting off high permeability formation selectively,expanding swept area,at the same time,its high interfacial activity could improve the efficiency of oil washing.The results show that the recovery rate of the laboratory sand-packing increases by 25.0%.It provides effective technical method for improving the oil recovery of inverted layered reservoirs.