注聚三采期岩电参数的实验

中国东部部分油田已进入三次采油期,储层注入聚合物溶液后,储层的物性、电性会发生相应的变化。为了查明储层内注入聚合物溶液后所发生的变化,模拟双河油田开发过程中设计的岩心注聚实验,通过观察注入聚合物的砂岩岩心的实验结果,得出了岩心驱替前后,岩心孔隙度和绝对渗透率变化不大、薄膜电位减小、阿尔奇公式中的孔隙度结构指数优增大,饱和度指数集中在1.4～1.7之间、电阻率变化呈“S"和斜躺“L”型减小等变化规律。注聚后孔隙度和渗透率的计算可以按常规测井评价方法进行,注聚前的薄膜电位明显大于注聚后的薄膜电位,因此注聚后在测井解释中要特别注意自然电位曲线的应用,在聚合物驱油过程中,岩心的电阻率变化规律与盐水驱油过程的电阻率相类似,故在测井评价中可直接使用水驱油田的饱和度的评价方法。

THE CORE EXPERIMENT OF THE INJECTION BY POLYMER IN TERTIARY OIL RECOVERY

When oilfields begin to assume tertiary oil recovery phase in the east part of China, physical properties and electric properties of pay zones will be uncertainly altered to a great extent due to the injection of polymer. In order to ascertain the changes of reservoir properties which have been affected by the polymer, the core experiments have been designed according to the reservoir behaviors in the period of tertiary oil recovery. Based on the core experiments from polymer injection region, this paper has identified that core porosity and permeability haven't changed, film potential has dropped off, porosity structural index has increased, the index of saturation of Archie's equation has focused on 1.4-1.7, and the resistivity changes are in the shapes of letters S and L. After polymer displacement, reservoir porosity and permeability can be calculated by conventional logging method. The values of film potential before polymer displacement are apparently bigger than that of after polymer displacement, so the application of spontaneous potential should be noticed after polymer displacement. During polymer displacement, the law of resisitivity change is similar to that of salinity water driving oil. So the method of saturation appraisal of waterflood can be directly used in logging assessment.