山东昌乐凹陷油页岩地球化学特征及成因探讨

Geochemical Characteristics and Genesis of the Oil Shale in Changle Sag,Shandong Province

山东昌乐凹陷油页岩出产于古近系五图群李家崖组,与济阳拗陷和潍北凹陷孔二段相当。利用有机地球化学方法对昌乐凹陷油页岩品质进行分析,结果显示该区油页岩有机质丰度较高、干酪根类型主要为Ⅰ型和Ⅱ1型,处于未熟-低熟阶段,具有较好的勘探开发前景。通过区域构造演化和气候变化分析,昌乐凹陷油页岩形成于郯庐断裂带左旋-右旋转换期,构造活动强度较弱加之温暖湿润的气候环境促成了油页岩的发育。油页岩与煤共生于水进体系域和高水位体系域之中,油页岩成矿模式为断陷湖沼型。

The oil shale of Changle sag exists in Lijiaya Formation of Wutu Group,corresponds to the stratum of 2nd Kongdian Formation in Jiyang depression and Weibei sag.By means of the organic geochemical theories and methods,the characteristics of oil shale in Changle sag are studied.The oil shale has a high organic matrix abundance.Its kerogen type is mainlytypeⅠ and typeⅡ1,at an immature-low maturity stage,has a strong potential for oil generation,so it has good prospects for oil and gas exploration.By analyses of the regional tectonic evolution and climate change,the oil shale of Changle sag are formated in left turn to right turn conversion period of Tanlu fault zone,weak tectonic activity coupled with warm and humid climate.The oil shale and coal co-exist in TST and HST.The oil shale metallogenic model belongs to the rift lake march type.