基于相渗分析纯岩石电阻率增大系数与含水饱和度关系

Relationship Between Rock Resistivity Increasing Coefficient and Water Saturation Based on Phase Percolation Analysis

岩石岩电实验表明电阻率增大系数与含水饱和度关系呈现非阿尔奇现象。基于岩石导电与渗流过程的相似性与差异性,分别建立纯岩石渗流与导电模型,尝试结合渗流特征探索岩石电阻率增大系数与含水饱和度的关系。建立岩石渗流模型,通过模型分析、公式推导和渗流实验数据,得到不同含水饱和度条件下水相渗流路径迂曲度比值表达式;建立纯岩石等效导电模型:将岩石孔隙空间划分为参与渗流的孔隙空间与不参与渗流的孔隙空间,2部分并联导电,结合渗流模型结论推导电阻率增大系数与含水饱和度的关系式,提出了差异渗流导电公式。该公式在一定条件下可退化为经典阿尔奇公式,其呈现的电阻率增大系数与饱和度关系趋势解释了岩石中存在的非阿尔奇现象。

The core electricity experiments show that the relationship between resistivity increasing coefficient and water saturation presents 'non-Archie'phenomenon in recent years.Based on the similarities and differences in rock conductivity and percolation process,we established rock percolation and conductivity models to explore the relationship between resistivity increasing coefficient and water saturation by combining with percolation characteristics.Firstly we set up rock percolation model to obtain the expression of aqueous phase flow path tortuosity ratio by analyzing the model and deducing formula with the percolation experimental data.Then we set up rock equivalent conductivity model.The principal is that the rock pore space is divided into participation seepage pore space and does not participate in the seepage of pore space,two parts of which are parallel conductive.Combined with rock percolation result,we deduced the relationship between resistivity increasing coefficient and water saturation and proposed a 'conductivity in different percolation formula'.This formula could be degenerated into the classic Archie under certain conditions.It presents the relationship trend of resistivity increasing coefficient and water saturation which explains the existence of rock'non-Archie phenomenon'.