水淹层地层水电阻率变化规律研究

On Variation Regularity of Resistivity of Mixed Formation Water in Water-flooded Zone

对于注水开发砂岩油田,随着注水强度的增加,储层水的变化由原始油层的束缚水特征逐渐过渡到注入水的特征,注入水与水淹层混合液之间的离子交换作用不再遵循简单的并联模型,相应的水淹层地层水电阻率具有较复杂的变化规律。在分析泥质砂岩注水开发体积模型的基础上,采用一种改进的并联模型,推导出不同注水条件下的混合液地层水电阻率的理论模型,重点对注水开发中、后期水淹层地层水电阻率的变化规律进行了理论分析与模拟,并结合岩心分析与激发极化电位测井解释成果进行应用对比,对水淹机理研究具有一定的指导意义。研究表明,在实际应用选择水淹层混合液电阻率时,可以根据含水饱和度的变化分3个不同的阶段选择不同的混合液电阻率值。

In flood development sand oilfield, as the water-intake per unit thickness increases, the reservoir water is gradually transitting into the injected water from the bound water in the original petro- leum reservoir. The ion exchange of blending fluid between the injected water and original water in flooded zone does not follow the simple parallel connection model. So, the resistivity change is complicated in flooded zone. Based on the waterflood development volume model of shaly sand, a modified parallel model is adopted. Proposed is a theoretical model of mixed resistivity of formation water under different waterflood conditions. Analyzed and stimulated are the changes of resistivity of formation water for water-flooded zone during middle and later period of oilfield development. Compared and analyzed is the result of core analysis and induced polarization well logging interpretation. These viewpoints are of great importance to watered-out mechanism research. The research indicates that we can choose different resistivity values depending on the three change periods of water saturation when we select the resistivity of formation water.