基于岩电参数和颗粒直径的渗透率模型在低孔隙度低渗透率储层中的应用

Application of the Permeability Model Derived from Petro-electrical Factors and Grain Diameters in Low Porosity and Low Permeability Formation

基于RGPZ渗透率模型分析了岩石中电流导通性能、孔隙结构连通性和渗透率之间的相互关系,并用低孔隙度低渗透率储层的实际测井数据估算的颗粒直径和岩心岩电分析数据预测渗透率。在RGPZ渗透率计算模型中,考虑了反映岩石电流导通特性的地层因素F和表征孔隙结构弯曲度的胶结指数m,以及岩石颗粒直径,三者均可由电测井数据和/或实验分析得到。利用前人发表的多类实验数据和鄂尔多斯某探区的3口井实际测井资料验证了RGPZ渗透率计算模型有效性和对低孔隙度低渗透率储层的适应性,验证结果表明RGPZ渗透率计算模型预测的渗透率在没有微裂缝井段与实测渗透率吻合较好,但在微裂缝发育层段,需要考虑微裂缝对岩电参数的影响。

Based on RGPZ model, the relationship among current conduction performance, pore structure connectivity and permeability is analyzed in this study, and the field logging data of a formation with low porosity and low permeability are used to estimate the grain diameter which has been integrated with petro-electrical parameters to predict the RGPZ permeability. In the RGPZ permeability model, we consider formation factor F, which indicates the rock current conduction characteristics, and the cementation index m that reflects the pore structure tortuosity, and rock grain diameter, all these three parameters can be obtained from electric logs and/or experimental analysis. Many previous published experimental data and field data of three wells from one exploration area of Ordos basin, where there are petro-physical analysis data and petro-electrical data, are used to verify the adaptability and effectiveness of RGPZ permeability prediction model. The checked results show that the permeability of RGPZ model is in good agreement with the measured permeability in well section without the micro-cracks, but the effect of micro-cracks on petro-electrical parameters should be considered in the section of developed micro-cracks.