Characteristics and origin of desorption gas of a transitional shale: A case study from the Lower Permian Taiyuan Formation shale, Ordos Basin, northern China

摘要

In China, marine shale and terrestrial shale have achieved significant breakthroughs. Comparing with marine shale and terrestrial shale, the research and exploration of transitional shale are still in the preliminary stage, and the content and origin of desorbed gas from transitional shales are poorly documented, thus limiting the understanding of gas generation and potential play elements. Geochemical characteristics of desorbed gas, including content and origin, are analyzed from 9 core samples of the Lower Taiyuan Formation shale from well SSL23 in the Ordos Basin, northern China. The results show that the Taiyuan Formation shale in the study area are characterized by high total organic carbon content of 2.70-9.00%, type III organic matter, and high T_(max) ranging from 461 to 520°C.