Pore structures and Seepage Characteristics of Sand-conglomerate Reservoirs of Baikouquan Formation in Triassic Mahu Sag, Northwestern Margin of Junggar Basin

The Triassic Baikouquan Formation in the slope area of the Mahu sag belongs to the tight glutenite reservoir. In order to discuss the pore structure type of the reservoir and its relationship with oil content in the study area, the characteristics of petrology, pore structure, seepage, and oil-bearing properties were studied by using the experimental methods of thin sections, high pressure mercury intrusion, nuclear magnetic resonance and visualized water flooding. The results show that the types of pore reservoirs in glutenite can be divided into residual intergranular, intragranular dissolved, intercrystalline pores and micro-cracks; the pore throat types are mainly sheet-like, point-like and bundle-like throats. The pore structure is divided into four categories. As pore structure tends worse, the oil content and the seepage capacity also gradually deteriorates.