Quantitative characterization of microscopic pore heterogeneity in tight sandstones and its reservoir significance: A case study of the Shanxi Formation in X area, Ordos Basin

This paper presents a new method to extract the face rate of casting a thin section image of tight sandstones from the Shanxi Formation in the eastern Ordos Basin based on Matlab software programming. A heterogeneity coefficient U is proposed according to face rate, which quantitatively characterizes microscopic pore heterogeneity. The reser-voir significance of the heterogeneity coefficient U and the relationship between reservoir physical properties and microscopic pore heterogeneity were discussed. The results show that the micro-heterogeneity of the tight sandstone reservoirs in X area is very strong and the micro-pore distribution is very heterogeneous. A larger heterogeneity coefficient U and a stronger reservoir heterogeneity is associated with poorer reservoir physical properties, and vice versa.The microscopic heterogeneity of tight sandstone reservoirs influenced the microscopic development characteristics of pore space (reservoir space and permeability). The quantitative evaluation of the heterogeneity coefficient of tight sandstone reservoirs can guide the selection of high-quality strata for production.