Genesis and source of Permian natural gas in well Qiatan-1 of piedmont depression, southwestern Tarim Basin

Recently, a significant breakthrough in natural gas exploration was achieved in well Qiatan-1 in the Permian carbonate strata of the Western Tianshan thrust belt in the piedmont depression of southwestern Tarim Basin, marking the discovery of a new exploration layer in the area. However, this region is characterized by multiple sets of source rocks and extremely complex sedimentary and structural features. Research on the genesis and source of the natural gas in well Qiatan-1 is insufficient, restricting its further natural gas exploration. Therefore, the study systematically investigated the genesis and source of the natural gas in well Qiatan-1 based on regional geological background, geochemical characteristics of the gas, and potential source rock features. The measured results showed that the natural gas in well Qiatan-1 was mainly composed of methane (83.53%), with a gas dryness coefficient (C1/C1-5) of 0.992, and contained relatively high levels of N2 (8.36%), CO2 (7.28%), and He (0.110%). The carbon i