Fine evaluation of extra-low permeability reservoirs based on the multi-well logging evaluation

With a strong heterogeneity and oil-bearing property, the member Chang 8 reservoir of Yanchang Formation in Jiyuan area, Ordos Basin is characterized by typical extra-low permeability. And it has complex reservoir parameters and reservoir distribution. This paper proposes an approach for evaluation of this kind of reservoirs. Based on core calibrating logging data, we build fine interpretation models of reservoir parameters according to logging data standardization. Through multi-well logging interpretation, the reservoir distribution and oil-bearing property are determined. Small sand bodies are identified based on different logging facies, and lithologic reservoir contrast is obtained by different physical and oil-bearing properties. Finally the control factors and distribution rules of extra-low permeability reservoirs in the area are defined. Therefore fine evaluation of extra-low permeability reservoir is realized based on multi-well logging.