Classification and evaluation of the hydrocarbon generation potential of Jurassic coal measures of Qaidam basin

Many types of coal-measure source rocks, mainly including mudstone, carbonaceous mudstone, coal and oil shale, were developed in Jurassic in Qaidam basin. Different types of source rocks, controlled by sedimentary environments, have significant difference in organic matter, organic matter type and hydrocarbon generation and expulsion models. Those traditional evaluation methods underestimated hydrocarbon generation potential of carbonaceous mudstone and coal. This study presents a quantitative evaluation method based on hydrocarbon yield of unit source rock, predicts quantitatively total hydrocarbon amount and total resource extent of source rocks. The results shows contribution ratio of carbonaceous mudstone to hydrocarbon generation of Jurassic and oil & gas resource was 44.8% and 41.7%, respectively, promoting resource potential of source rocks in Jurassic of Qaidam basin, improving greatly resource potential of coal-type gas, which has guiding significance for gas exploration in Qaidam basin.