Study on oil-rich coal occurrence characteristics and sedimentary environment in Yushen Mining Area

The abundance of oil-rich coal resources in Yushen Mining Area provides high-quality raw materials for China's coal chemical industry,but the occurrenc e characteristics of oil-rich coal in Yushen Mining Area are not clear,which seriously restricts the efficient uilization of oil-rich coal resources. To find out the distribute ch aracteristics and sedimentary environment of oil-rich coal in Yushen Mining Area will provide geological basis for further exploration,development,and utilization,the No. 2-2coal and No.5-2coal of Yan'an Formation in study area were taken as study objects.We examined the occurrence characteristics of oil-rich coal via classifying tar yiel d of raw coal,and discussed the sedimentary environment of No.2-2coal and No.5-2coal oil-rich coal according to the geochemical characteristics during forming proces s of coal seam,such as ash composition index, sulfur content,mirror-inert ratio,etc.and kerogen characteristics of the hydrocarbon-forming parent material.The results sh owed that the yield of raw coal coke oil of No.2-2coal is 5.3% ~ 15.3%,with an average of 10. 1%, the yield of raw coal coke oil of No.5-2coal is 5. 1% ~ 14.6%,with an aver age of 9.9%,the oil-rich coal mainly distributes in the study area,but oil-high coal partly.On the plane,the tar yield of raw coal tends to increase from west to east,from th e delta plain to the shore shallow lake,and vertically,gradually mount from bottom to top,the high oil coal moves along the shore shallow lake from northeast to southwe st.The oil-rich coal in the Yushen Mining Area was formed in the declining paleo-tectonic environment of the Ordos Basin,the paleogeographic environment of the shore shallow lake with strong reducibility,and the warm and humid paleo-climatic environment,and the occurrence of organic materialsare and multy-layer coal seam provided material basis of oil generation.