Analysis of Geological Conditions of Permian Shale Oil and Gas in the Southwestern Depression of the Tarim Basin, Northwest China

Permian shale is an important source rock in the depression of southwestern Tarim Basin. Oil and gas from such fields as Akemomu, Kekeya, Kedong1 and Duwa1 are originated from the Permian system, while research on its shale geological conditions is rarely reported. Based on the comprehensive analysis of the tectonic and sedimentary development and its evolution characteristics, the authors focused on the thickness, distribution, geochemistry and reservoir characteristics of the Permian shale, and also discussed the coupling relationship between evolution of tectonic, sedimentary and hydrocarbon generation. The results show that the accumulated thickness of Permian shale is between 50 and 400 m, mainly distributed in Yecheng sag and Hetian sag with shallow sea shelf facies and sea-land transitional facies. The Quaternary Himalayan movement plays an important role in promoting the hydrocarbon generation of the Permian shale. Comprehensive analysis suggests that the Permian shale in the southwestern Tarim depression has good conditions of shale gas generation and reservoir, and is the potential stratum shale gas exploration. The Yecheng sag and Hetian sag are favorable for shale oil and gas exploration, which needs to be further drilled and verified.