稠油油藏聚合物驱相对渗透率曲线及驱油效率影响因素

Influence Factor of Relative Permeability Curve and Displacement Efficiency of Polymer Flooding in Heavy Oil Reservoir

谢 坤 卢祥国 姜维东 康晓东 田春雨

XIE Kun LU Xiang-Guo JIANG Wei-Dong KANG Xiao-Dong TIAN Chun-Yu

针对目的海上稠油油藏地质特征、流体性质和现场施工工艺，通过岩心驱替实验、岩心CT扫描和理论分析，开展了岩心渗透率、水冲刷作用及原油黏度对聚合物驱相对渗透率和驱油效率影响研究。结果表明，随岩心渗透率增加，油相相对渗透率降低，驱替相渗流阻力减小，水相相对渗透率增高，波及区域面积增大，两相流跨度带增大，最终采收率增加；水冲刷对岩心孔隙结构的“携屑”和 “剥蚀”作用会扩大孔喉半径，增大岩心渗透率，其对相渗透率曲线和驱油效率的影响与岩心渗透率增大造成的影响相同；随原油黏度增加，油水两相相对渗透率降低，驱替相黏性指进现象加剧，渗流阻力增加，波及区域面积减小，两相流跨度带减小，最终采收率降低。

The impact of core permeability, water washout and crude oil viscosity on relative permeability and the displacement efficiency of polymer flooding were studied through core displacement experiment, core CT scanning and theoretical analysis, aiming at reservoir geological characteristics, fluid properties and field construction technology of the offshore heavy oil reservoir. The results showed that, with the increase of core permeability, the oil phase relative permeability reduced, the seepage resistance of displacing phase decreased, and the water phase relative permeability increased, the swept volume become bigger, two-phase flow span got wider, resulting in the ultimate oil recovery was enhanced. The function of ‘cleaning’ and ‘erosion’ that water washout exerted on core pore structure would enlarge the pore throat radius, increase core permeability, and its influence on relative permeability curve and displacement efficiency was similar to the influence of the increase of the core permeability. With viscosity of the crude oil increasing, oil/water phase relative permeability reduces, displacing phase viscous fingering phenomenon aggravated, seepage resistance increased, and the swept volume became smaller, two-phase flow span got narrower, resulting in the ultimate oil recovery decreased.