宁夏炭山中侏罗统延安组油页岩赋存特征及形成环境分析

Formation Environment and Occurrence Characteristics Analysis on Jurassic Yanan Group Oil Shale of Carbon Mountain in Ningxia

固原市炭山地区(盆地)是一个小型断陷盆地,根据钻探、测井、室内测试分析资料,综合研究了该盆地内油页岩赋存特征与形成环境。结果表明,盆地内油页岩存在3种不同的赋存方式,第一种为煤层本身,赋存于泥岩中;第二种为煤层夹炭质泥岩,赋存于泥岩与粉砂质泥岩中;第三种为泥岩,赋存于粉砂质泥岩与细砂岩间,或为煤层底板。油页岩主要发育在水进体系域和高水位体系域中,属于湖泊-沼泽相沉积环境;受古构造、沉积环境、古地貌因素的控制,油页岩成因类型为湖沼腐泥腐殖型。

Carbon mountain(basin)located in Guyuan city is a small fault basin.According to the drilling,well logging,the comprehensive research of laboratory test and analysis data,shale occurrence characteristics and formation environment are analyzed.There are three different types of oil shale occurrence mode.The first kind of shale is the coal seam itself,existed in mudstone.The second clip is carbonaceous mudstone shale for coal,occurred in mudstone and silty mudstone.And the third is for mudstone,oil shale occured in silty fine sandstone and mudstone or in coal floor.The oil shale develops in the water-inflow system and the high water level system domain,which belongs to the lacustrine and swamp facies sedimentary environment.Under the control of paleotectonics,sedimentary environment and paleogeomorphology,the oil shale is humic type of lake bog and mud.