Distribution of the Frasnian strata in Hunan Province and shale gas prospects

Shale of the Frasnian Shetianqiao Formation in Hunan Province is an important target for shale gas exploration. The Shetianqiao Formation and its multiple coeval strata characterized by regional rapid lithofacies differentiation lead easily to confusion in quotation and difficulty in outcrop identification, which restrict its shale gas exploration process. By clarifying the historical evolution of Shetianqiao Formation and its corresponding strata, their distribution area and application area were defined and delineated. Based on the variation of rock assemblage, organic carbon and existing exploration results of the Shetianqiao Formation, it is proposed that the Xinhua-Lianyuan and Shaodong region with higher inputing of terrestrial detritus are the favorable prospects for shale gas exploration, and exactly locating the range of inter-platform basin in carbonate platform is the key role for further shale gas exploration.