摘要
基于润湿指数(WI)为-0.7~0.7的2种具有可对比性的特低渗透和中高渗透人造仿真岩心,探讨润湿性对其水驱特性影响的主要差异。研究结果表明,特低渗透与中高渗透均质岩心相比,润湿性对水驱特性影响趋势相似;岩心的亲油性和亲水性越强(越偏离中等润湿),水驱前缘突破速度越快,平均含水上升速率越大,水驱平衡压力梯度越高,无水驱油效率和极限驱油效率越低。特低渗透与中高渗透岩心润湿性对水驱特性影响的差异体现在特征参数量值的影响幅度上:润湿指数对特低渗透岩心平均含水上升速率、水驱平衡压力梯度、极限驱油效率等的影响幅度远高于中高渗透岩心。与中高渗透油藏相比,特低渗透油藏的水驱特性对润湿性更敏感;特低渗透油藏的润湿性从油湿向中等润湿转变对于提高水驱油效率的技术潜力远大于中高渗透油藏。
In this paper,two kinds of synthetic cores with a wettability index(WI)in the range of−0.7-0.7 are comparatively used to explore the main difference in the influence of wettability on waterflooding characteristics of ultra-low permeability and medium-high permeability cores.The results reveal that for the homogeneous cores with ultra-low and medium-high permeability,the influence trend of wettability on waterflooding characteristics is similar.Specifically,stronger lipophilicity and hydrophilicity of cores(more deviated from the medium wettability)are accompanied by the faster breakthrough of waterflooding front,a higher rising rate of average water cut,a higher waterflooding equilibrium pressure gradient,and lower water-free oil displacement efficiency and ultimate oil displacement efficiency.The difference is reflected in the magnitude of the influence of the characteristic parameter values.Compared with the medium-high permeability cores,the ultra-low permeability cores are much more susceptible to the influence of the wettability index on aspects including the rising rate of average water cut,equilibrium pressure gradient,and ultimate oil displacement efficiency.The waterflooding characteristics of ultra-low permeability reservoirs are more sensitive to wettability compared with those of medium-high permeability reservoirs.The transition of wettability from oil-wet to medium-wet in ultra-low permeability reservoirs has much greater technical potential for improving oil displacement efficiency than that in medium-high permeability reservoirs.
作者
冯雪钢
岳湘安
安维青
邹积瑞
FENG Xuegang;YUE Xiang’an;AN Weiqing;ZOU Jirui(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing City,102249,China;Key Laboratory of Petroleum Engineering,Ministry of Education,China University of Petroleum(Beijing),Beijing City,102249,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2022年第2期94-99,共6页
Petroleum Geology and Recovery Efficiency
基金
国家科技重大专项“低渗/致密油藏高效开采与提高采收率新技术”(2017ZX05009-004)
国家自然科学基金项目“致密油储层提高采收率关键理论与方法研究”(51334007)。
关键词
润湿性
水驱
特低渗透
中高渗透
含水率
压力梯度
wettability
waterflooding
ultra-low permeability
medium-high permeability
water cut
pressure gradient
