多参数约束的致密砂岩储层渗透率预测方法——以川西拗陷中江气田沙溪庙组为例

摘要

For tight sandstone reservoirs,the permeability is more comprehensive than the porosity in the aspect of accumulation and productive competence of reservoirs.Therefore,it is necessary to carry out the prediction of reservoir permeability and lay a foundation for the meticulous evaluation of reservoir based on permeability.The correlation analysis of permeability with rock composition,grain size,sorting,and micro-fracture development degree reveals that the main geological factors affecting the permeability are porosity,grain size and micro-fracture development degree.On the basis of prediction models of porosity, grain size and micro-fracture development degree respectively, a geological and seismic multiple parameter comprehensive prediction model is established through the multiple parameter matching method involved in grain size,sand body configuration,fault distance and deformation intensity.It shows that the permeability calculated by the proposed new model is not only consistent with the virtual permeability,but also possesses much higher prediction accuracy.%以川西拗陷中江气田沙溪庙组为例,开展储层渗透率的预测,为建立基于渗透率的储层精细评价奠定基础.通过对渗透率与碎屑组分、粒度、分选性及微裂缝发育程度的相关性分析,认为影响渗透率的地质因素主要是孔隙度、岩石粒度及微裂缝发育程度.在分别建立孔隙度、粒度及裂缝发育程度预测模型的基础上,通过多参数拟合方法建立了基于"粒度、砂体构型、到断层的距离、构造形变强度及多属性裂缝预测"的地质-地震约束的多参数渗透率综合预测模型.采用新模型计算的渗透率与实测渗透率具有更好的一致性,比单一的孔-渗预测模型具有更高的预测精度.