Evaluation of organic geochemical characteristics and hydrocarbon generation potential of coal measure mud shale

In order to study the organic geochemical characteristics of the marine-continental coal-sediment shale, a total of 444 rocks from 10 mud shale gas wells in the Carboniferous-Permian coal system in Yushe-Wuxiang Block of Qinshui Basin were collected, and the total organic carbon content (TOC) was developed. Based on the analysis of rock pyrolysis and vitrinite reflectivity, the organic geochemical characteristics of the Carboniferous-Permian marine-continental coal-sediment mud shale in Yushe-Wuxiang Block were studied. The results show that the average values of TOC from Xiashihezi, Shanxi and Taiyuan Formations in Yushe-Wuxiang Block are 0.90%, 2.38% and 2.66%, respectively. The organic matter types of the mud shale are mainly Type III Kerogen. The maximum pyrolysis peak temperature (Tmax) and vitrinite reflectance (Ro) of most mud shale samples are greater than 465 ℃ and 2.0%, respectively, suggesting that the over-mature dry gas stage, and the conversion rate is higher. The organic geochemical characteristics of Carboniferous-Permian coal measure shales indicated that the Taiyuan formation is the preferred horizon for shale gas exploration, and Shanxi formation has a certain mud shale gas resource potential while Xiashihezi Formation has the lowest organic matter abundance and has no resource significance.