延安气田致密砂岩储层物性下限界定OA

The Yan'an gas field is characterized by strong reservoir heterogeneity and complex pore structure,which pose great challen-ges to determining the lower limits of reservoir properties.The commonly used empirical coefficient method,mercury intrusion parameter method,and nuclear magnetic resonance method have significant differences in determining the lower limits of reservoir properties.In this article,the weights of the lower limits of reservoir properties obtained by different methods were analyzed using the analytic hierar-chy process,and the lower limits of physical properties of tight sandstone reservoirs in Yan'an gas field were comprehensively calculated using the weighted average method.The results show that the lower limit of porosity in the Yan'an gas field reservoir calculated by vari-ous methods is 2.69%～6.92%,and the lower limit of permeability is(0.002 3～0.042 0)×10-3 μm2.By the analytic hierarchy process(AHP),it is known that the weight of the lower limit of porosity determined by the minimum pore throat radius of the movable fluid is maximum,while the weight of the lower limit of permeability determined by the mercury intrusion parameter method is maxi-mum.The lower limits of porosity and permeability in the tight sandstone reservoirs in the study area based on the weighted average method are 5.06%and 0.011 8×10-3 μm2,respectively.The research results can provide a reference for the exploration and develop-ment of tight sandstone gas reservoirs in Yan'an gas field.