阿尔奇公式的适用性分析及其拓展

阿尔奇年代的储层孔隙结构简单，岩石孔隙可以被实验电解质完全充填，随着油气田勘探开发的逐步深入，对储层孔隙结构复杂程度的认识更加深入.发现岩石孔隙不仅有有效孔隙，也有无效孔隙.不仅有效孔隙导电，无效孔隙也导电，某些岩石骨架同样也导电.如何去除无效孔隙和其他各类岩石附加导电现象的影响，正确评价有效孔隙的贡献往往令人困惑.笔者发现：通过岩石电阻率计算地层因数只是在没有岩石附加导电环境下的特殊应用，在更为普适的条件下，地层因数实质是借助岩石电阻变化率反映孔隙连通性的重要参数.与物理学位移、速度的关系类似，电阻率和电阻变化率之间同样有着密切关系.这一观点的提出为在复杂孔隙结构条件下评价储层孔隙有效性提供了手段.

Limitation analysis and modification of the Archie equation

The Archie equation is widely used to estimate the water saturation by its electrical conductivity of a rock. However, the conductivity of a rock consists of not only the water saturation but also the rock itself, so that conductivity exists even for a rock completely without porosity. To distinguish between the two effects, solutions with different salt concentrations are used. Here, we provide evidence that the resistivity of a rock with effective saturation varies when the salt concentration changes, similar to the relationship between displacement and speed, while the resistivity remains unchanged for the rock without permeability to their porosity. It is concluded that water saturation in complex porous reservoirs will be more accurately calculated by adding the factor of resistivity changes in the Archie equation.