Pore Structure and Physical Properties of Sandstone Reservoirs: A Case Study of Chang 6 Member in Antaolin Area, Ordos Basin

Abstract

This study takes the Chang 6 sandstone reservoir in the Antaolin area as the research object. Through comprehensive experimental methods including casting thin sections, scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP), we systematically analyzed the microscopic pore-throat structure characteristics of the reservoir. The main understandings are as follows:In terms of petrological characteristics, the study area mainly develops two types of reservoir rocks: feldspathic sandstone and lithic arkose. The cements contain relatively abundant carbonate minerals and clay minerals, with minor amounts of siliceous and feldspar cements. The clay minerals are mainly composed of chlorite and illite. The rock pore structure is complex, with poor throat sorting uniformity.Pore structure research shows that the sandstone reservoir in the study area develops a diversified pore system. Residual intergranular pores and intergranular dissolution pores constitute the main reservoir space. The pores exhibit low cement filling degree and minimal matrix content.