Lithofacies palaeogeography of the Carboniferous and Permian in the Qinshui Basin, Shanxi Province, China

The Qinshui Basin in the southeastern Shanxi Province is an important area for coalbed methane (CBM) exploration and production in China, and recent exploration has revealed the presence of other unconventional types of gases such as shale gas and tight sandstone gas. The reservoirs for these unconventional types of gas in this basin are mainly the coals, mudstones, and sandstones of the Carboniferous and Permian; the reservoir thicknesses are controlled by the depositional environments and palaeogeography. This paper presents the results of sedimentological investigations based on data from outcrop and borehole sections, and basin-wide palaeogeographical maps of each formation were reconstructed on the basis of the contours of a variety of lithological parameters. The palaeogeographic units include the depositional environments of the fluvial channel, flood basin (lake), upper delta plain, lower delta plain, delta front, lagoon, tidal flat, barrier bar, and carbonate platform.