An analysis of resource potential of Upper Paleozoic shale gas in Guizhong depression

Abstract：Guizhou depression has experienced three stages of tectonic evolution, i.e., the early Proto-Tethys rift basin and the late orogenic fold，ancient Tethys rift basin stage，and the Neo-Tethys oroganic transformation phase．With the large-scale transgression in the early Devonian，there developed platform sag and slope facies dark shale and coal-bearing coast swamp facies framework in this area，which mainly included Lower Devonian Tangding Formation black shale，Middle Devonian Luofu Formation black shale and lower Carboniferous Yanguan Formation black shale．Researches have shown that the upper Paleozoic marine shale，characterized by high abundance of organic matter，good types and high-over- mature stage of evolution，has favorable conditions for shale gas．Up to date，Upper Paleozoic shale has been found in many gas shows in Guizhong depression，which has similar geological condition to typical shale gas basins in eastern United States (Appalachian，Ford Voss and Michigan basin). According to the analogy method，the amount of Upper Paleozoic shale gas resources is preliminarily estimated to be about 12.34x 1012m3 in the depression，which indicates that the area had huge shale gas resource potential．