榆神矿区富油煤赋存特征及其沉积环境研究

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

榆神矿区丰富的富油煤资源为我国煤化工提供了优质的化工原料,但是榆神矿区富油煤的赋存特征尚不明确,严重制约了富油煤资源的高效利用。为查明榆神矿区富油煤的分布特征和沉积环境,对该地区富油煤的进一步勘探和开发利用提供地质依据,以榆神矿区延安组2-2煤和5-2煤为研究对象,通过原煤的焦油产率分级划分,对榆神矿区的富油煤赋存特征进行研究,并根据灰成分指数、硫分、镜惰比等煤层形成过程中的地球化学特征及成烃母质的干酪根特征,探讨2-2煤和5-2煤层富油煤的沉积环境。研究结果表明:2-2煤原煤焦油产率5.3%~15.3%,平均10.1%,5-2煤原煤焦油产率5.1%~14.6%,平均9.9%,榆神矿区主要以富油煤为主,局部分布为高油煤。平面上,原煤焦油产率有由西向东、由三角洲平原向滨浅湖方向呈增高的趋势,垂向上,自下而上逐渐增高,高油煤随着滨浅湖由东北向西南迁移。榆神矿区富油煤形成于持续稳定下降的鄂尔多斯盆地古构造环境、还原性较强的滨浅湖古地理环境及温暖潮湿的古气候环境。含腐泥型母质为生油提供了物质基础。

The abundance of oil-rich coal resources in Yushen Mining Area provides high-quality raw materials for China’s coal chemical industry,but the occurrence characteristics of oil-rich coal in Yushen Mining Area are not clear,which seriously restricts the efficient utilization of oil-rich coal resources.To find out the distribute characteristics 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 yield 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 process 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 showed 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 average 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 the 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 southwest.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.