Sedimentary lithofacies paleogeography and pore characteristics of the organic-rich mud shale of the upper Triassic Baiguwan Formation in Xichang basin

Organic-rich mud shale in transitional facies is an important target for shale gas exploration.In this paper, the paleogeographic features, micro-pore types and pore structures of the organic-rich mud shale of the Upper Triassic Baiguowan Formation in Xichang Basin were studied.Lake facies and delta facies are the main sedimentary facies of organic-rich mud shale in the Baiguowan Formation. Small pores, which are dominant, followed by micropores, occurred in the organic-rich mud shale in the Baiguowan Formation. The average pore size was between 5.56 nm and 56.89 nm, the average specific surface area was 9.44m²/g, and the average total pore volume was 0.0187cm³/g. Shale gas was mainly formed in shore-shallow lake subfacies and semi-deep lake subfacies, and mainly adsorbed in the small pores and micropores of the organic-rich mud shale. In general, the organic-rich mud shale of the Baiguowan Formation in Xichang basin is potential for exploration of shale gas.