鄂尔多斯盆地南缘长7烃源岩地球化学特征与沉积环境  

Geochemical characteristics and sedimentary environment of Chang 7 source rocks,Southern Ordos Basin

作　　者：王广利[1,2] 李阳阳 王一帆 高兴[1,2] WANG Guangli;LI Yangyang;WANG Yifan;GAO Xing(State Key Laboratory of Petroleum Resources and Prospecting in China University of Petroleum(Beijing),Beijing 102249,China;College of Geosciences in China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)地球科学学院,北京102249

出　　处：《中国石油大学学报（自然科学版）》2024年第1期91-103,共13页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金面上项目(42072148)。

摘　　要：鄂尔多斯盆地南缘出露多处典型长7段页岩剖面,为了加深该区域烃源岩的研究,对35个烃源岩样品开展有机碳含量测定、岩石热解分析、饱和烃气相色谱-质谱分析、微量元素含量测定等测试分析,研究其地球化学特征,分析其有机质来源及沉积环境。结果表明:暗色页岩发育于淡水和还原的半深湖—深湖环境,沉积期气候温暖湿润,适宜生物发育,Mo元素高度富集,指示湖泊富营养化,初级生产力高;物质来源为藻类等低等水生生物和陆地植物的混合来源,但藻类等低等水生生物是主要来源;源岩有机质高度富集,总有机碳(TOC)平均值为23.51%,高于陆相优质烃源岩的丰度标准;有机质以腐泥—混合型为主,生烃潜量S1+S2均值为112.93 mg/g,生烃潜力良好;岩石热解峰温及生物标志化合物参数,指示达到成熟热演化程度,具有勘探潜力。The study focused on the typical shale profiles of the Chang 7 member extensively exposed along the southern margin of the Ordos Basin.To gain insights into the formation of source rocks and the prevailing sedimentary environment,detailed geochemical analyses were conducted on 35 outcropped source rock samples collected from Tongchuan areas.These examinations include total organic carbon(TOC)analysis,rock-eval pyrolysis,GC-MS of saturated hydrocarbons,and trace elements analysis.The findings suggest that the organic-rich black shales were deposited within a semi-deep lacustrine environment characterized by freshwater and reducing bottom water conditions.The climate was warm and humid fostering the thriving of algaet during the sedimentary period of Chang 7.The presence of highly enriched Mo elements indicated lake eutrophication and high primary productivity,with organic matter primarily contributed by algae.The source rocks are highly enriched in organic matter,with 23.51%of TOC and 112.93 mg/g of S 1+S 2 in average.Furthermore,the organic matter within the source rocks predominantly comprised a sapropelic-mixed type,indicative of substantial hydrocarbon generation potential.The peak temperature of rock-eval and biomarker ratios suggested that the source rock has reached the threshold of hydrocarbon generation,indicating promising exploration potential.

关 键 词：鄂尔多斯盆地 铜川地区 有机地球化学特征 烃源岩评价 有机质来源 沉积环境 

分 类 号：TE122.1[石油与天然气工程—油气勘探]