Characteristics of Reservoir Microscopic Pores and Throats and Their Influence on Reservoir Physical Properties in Huangliu Formation of DF Area, Yinggehai Basin

Key words: 
• pore-throat ratio /
• low permeability reservoir /
• Huangliu Formation /
• DF area /
• Yinggehai Basin

Abstract: Based on the constant speed mercury injection experiment, as well as the test data of porosity and permeability, characteristics of reservoir micro pores and throats and their influence on reservoir physical properties are analyzed in the Huangliu Formation of DF area, Yinggehai Basin. The results indicate that reservoir physical properties of the Huangliu Formation are mainly characterized by medium porosity and medium-low permeability, but with great differences in DF area. Besides, there is a relatively concentrated distribution of reservoir pore radius, while a strong inhomogeneous distribution of throat radius and the pore-throat ratio. For poor physical property reservoirs, small throats account for a higher percentage, and pore-throat ratio is also higher. On the contrary, for good physical property reservoirs, big throats account for a higher percentage, and pore-throat ratio is lower. The size of throat and its distribution are the key factors that affect the reservoir permeability, which is mainly controlled by large throats with lower percentage. Moreover, affected by sedimentation, small average throat radius of the reservoirs is the main reason for the formation of the low permeability reservoirs in the Huangliu Formation of DF area, Yinggehai Basin.