黔北地区五峰组-龙马溪组页岩沉积环境及有机质富集机理  

Sedimentary environment and organic matter enrichment mechanism of Wufeng-Longmaxi shale in the northern Guizhou area

作　　者：连梦利 刘达东 林瑞钦 王奕松 石富伦 蔡俊滢 范青青 张子亚 赵福平 陈祎 杜威 LIAN Mengli;LIU Dadong;LIN Ruiqin;WANG Yisong;SHI Fulun;CAI Junying;FAN Qingqing;ZHANG Ziya;ZHAO Fuping;CHEN Yi;DU Wei(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing,Beijing 102249,China;Key Laboratory of Unconventional Natural Gas Evaluation and Development in Complex Tectonic Areas,Ministry of Natural Resources,Guiyang 550004,China;Guizhou Institute of Petroleum Exploration and Development Engineering,Guiyang 550004,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]自然资源部复杂构造区非常规天然气评价与开发重点实验室,贵州贵阳550004 [3]贵州省油气勘查开发工程研究院,贵州贵阳550004

出　　处：《中南大学学报（自然科学版）》2022年第9期3756-3772,共17页Journal of Central South University:Science and Technology

基　　金：贵州省地勘基金资助项目(208-9912-JBN-L1D7);中国石油大学(北京)青年拔尖人才项目(2462021BJRC010)。

摘　　要：系统采集黔北地区两口典型井的页岩样品,开展古氧化还原、古生产力和陆源碎屑等条件的分析,揭示富有机质页岩形成的主控因素。研究结果表明:黔北地区五峰组—龙马溪组黑色页岩主要受控于氧化还原条件的影响,同时,古生产力水平对有机质富集具有一定的影响,而陆源碎屑输入的影响较小。因此,黔北地区五峰组—龙马溪组富有机质黑色页岩的发育主要受有机质保存条件的影响,属于“保存模式”。五峰组沉积早期,由于宽阔流通的海洋环境,还原性较低从而导致了低的有机质富集;五峰组沉积后期,在构造作用形成的缺氧条件下,加上高的古生产力促进了有机质的富集;龙马溪沉积前期主要由强还原条件控制,并受到陆源碎屑输入的一定影响,在高古生产力水平促进作用下形成了厚层的富有机质页岩。龙马溪组沉积后期,缺氧条件被破坏,加上低的古生产力水平,导致有机质丰度较低。The shale samples from two typical wells in northern Guizhou were systematically collected,and paleoredox,paleoproductivity and detritus input conditions were analyzed to reveal the main controlling factors for the formation of organic-rich shale.The results show that the black shale of Wufeng Formation—Longmaxi Formation in northern Guizhou is mainly controlled by the influence of redox conditions.Meanwhile,the paleoproductivity level has a certain influence on the enrichment of organic matter,while the influence of terrigenous clastic input is limited.Therefore,the development of organic-rich black shale in Wufeng—Longmaxi Formation in northern Guizhou is mainly affected by the preservation conditions of organic matter,which belongs to the"preservation mode".During deposition of the lower Wufeng Formation,the northern Guizhou area was in an open environment,resulting in low abundance of organic matter;conversely,the upper Wufeng Formation was in a restricted environment,with anoxic water column and high paleoproductivity,which benefits the formation of organic-rich shale.The lower Longmaxi Formation was mainly in a strongly reduced environment,with high paleoproductivity and weak influence of terrigenous input,together resulting in the deposition of thick organic-rich shales.During deposition of the upper Longmaxi Formation,the anoxic condition was destroyed,coupled with low paleoproductivity,resulting in low organic matter abundance.

关 键 词：黔北 五峰组—龙马溪组 古环境 有机质富集 

分 类 号：TE1[石油与天然气工程—油气勘探]