Influencing factors of gas content evaluation for shale gas: a case study of Lower Paleozoic Wuling fold belt in Upper Yangtze Basin

Factors of shale gas accumulation can be divided into the external and internal factors，according to accumulation mechanism and characteristics of shale gas． The internal factors mainly refer to parameters of or- ganic geochemistry，mineral components and physical parameters． Six factors were presented in this study，i．e． organic matter，maturity，quartz，carbonate，clay mineral and pore． The external factors mainly refer to geolog- ic environment of shale gas reservoir，including four factors: temperature，pressure，depth and thickness． Based on the experiment results of 26 samples of drilling cores from Wuling fold belt in Lower Paleozoic Silurian of the Upper Yangtze Basin，combined with the integrated analysis of geology，logging and test，the correlation of the gas content of shale gas to the above-mentioned ten factors was concluded． Six important evaluation indi- cators were preliminarily established in the gas-bearing core area of marine shale in the Upper Yangtze Basin．