山东昌乐五图油页岩特征及形成环境

Characteristics and depositional environment of oil shale,Wutu oilfield,Changle area,Shandong Province

利用地球化学评价与环境分析方法研究了山东昌乐五图古近系始新统李家崖组油页岩的特征及形成环境,认为油页岩含油率中等,平均为8.36%,灰分含量为59.61%,发热量为10.04MJ/kg,属于低灰分、中含油率型油页岩。油页岩有机质丰度较高,平均有机碳含量为19.23%,生烃潜力平均值为95.21mg/g,氢指数较高,其平均值为488.08×10^(-6),氯仿沥青"A"平均含量为0.533 7%,油页岩具有较好的生烃潜力,为优质油页岩;油页岩有机质类型以Ⅰ—Ⅱ_1型为主,镜质组反射率平均值为0.43%,最大热解峰温为422～446℃,油页岩处于未成熟—低成熟演化阶段。昌乐五图油页岩母质来源为淡水湖相藻类与高等陆源有机质,形成于还原的淡水湖沼相环境。

By means of geochemistry theories and methods,the characteristics and forming environment of oil shale in Lijiaya formation of Eocene in Wutu oilfield of Changle are studied.The oil-bearing rate is middle,and the average value up to 8.36%, the ash content 59.61%and the caloric value 10.04 MJ/kg,so it belongs to the oil shale with low ash and middle oil-bearing rate.The organic abundance of the oil shale is high,the average content of organic carbon is 19.23%,the average value of 5,+ S_2 is 95.21 mg/g,the average value of HI is 488.08×10^(-6),and the average content of chloroform asphalt 'A' is 0.5337%, which indicate that the oil shale has favorable potential for hydrocarbon generation and is high-quality.The types of organic matter of the oil shale are mainly typeⅠtoⅡ_1,the average value of R_o is 0.43%,the value of T_(max) is between 422℃and 446℃,which shows that oil shale is at immature-low mature evolutionary stage.The organic matter sources of the oil shale are algae of fresh lake and high terrestrial organic matters.And,the oil shale is deposited and formed in fresh lacustrine environment with reduction condition.The research results may supply reference for evaluating potential of oil shale in Wutu oilfield and its surrounding areas.