Geological conditions of Ordovician shale gas and optimization for prospective areas in the Lower Yangtze region

The Hule Formation of Middle Ordovician and the Ningguo Formation of Lower Ordovician in the Lower Yangtze region are the new interest of exploration for shale-gas intervals, thus it is highly necessary to undertake analysis of geological conditions and optimization work for prospective areas in this area. Starting from analysis of structure and sedimentary setting of black shale, this study investigated geochemistry, reserviors and distribution of Ordovician black shale using rgional geological and drilling data. The results show that the shale beds of the Hule Formation of Middle Ordovician and the Ningguo Formation of Lower Ordovician in the study area are characterized by large effective thickness with single layer thicker than 30 m, high content of organic matter, moderate thermal evolution, and high content of brittle minerals. The Ordovician shale in the Lower Yangtze region is of the favorable conditions for formation and accumulation of shale-gas and of good resource potential. The present study also suggests that the Ningguo area of Anhui Province and Chun’an-Tonglu area of Zhejiang Province are the two prospective areas for shale-gas exploration in the Lower Yangtze region.