Development characteristics and controlling factors of coal-measure source rocks in the global Tethys region

Under the control of tectonic activity in the Tethys region, a series of basins with coal measure source rocks developed, and the Tertiary coal in the circum Pacific belt is characterized by "hydrogen-rich" and has great hydrocarbon generation potential.This type of coal measure strata is an important source rock in petroliferous basins along the southeast coast of China.Therefore, it is particularly important to systematically analyze the development characteristics and controlling factors of coal measure source rocks under the Tethys background. Based on the systematic analysis of the development age, environments, geochemical characteristics and biomarker characteristics of the coal measure source rocks in the Tethys region, the controlling factors affecting the development of the coal-measure source rocks are summarized, and the favorable development conditions and controlling factors of high-quality coal-measure source rocks are clarified. The research results show that the coal-measure source rocks under the control of the Tethyan region are mainly developed in the basins under the extensional background of the coastal areas of Southeast Asia, mostly in the marine-terrestrial transitional facies sedimentary environment during the rifting period, and the development age is consistent with the period of Tethys tectonic activity.The development of coal-measures source rocks is controlled by many factors, such as paleovegetation, paleoenvironment, lithofacies paleogeography, terrigenous organic matter supply, tectonic activity intensity, sedimentation rate and so on. The factors are interrelated and influence each other, which can be divided into three types: parent source factor, tectonic-sedimentation factor and preservation factor.The plant types rich in the chitinous and hydrogen-rich vitrinites are the necessary parent source conditions for the formation of hydrogen-rich coal. The favorable coal accumulation environment and stable tectonic background are the key factors for the large-scale development of coal measure source rocks. Appropriate water conditions and reduction environment are important factors for the preservation of organic matter. The coal measure source rocks in the southeast coastal basins of China have great hydrocarbon generation potential. The coal measure source rocks are rich in resin in the Xihu Sag of the East China Sea basin, the coal measure source rocks are rich in spores and pollen in the Pearl River Mouth Basin, and the coal measure mudstone is widely developed in Qiongdongnan Basin, which has great exploration prospect.