摘要
鄂尔多斯盆地石炭系—二叠系海陆过渡相页岩气的研究主要集中在山西组山_(2)段泥页岩,山_(2)^(3)亚段是山_(2)段泥页岩中有机质最为丰富的层段。对柳林县成家庄剖面进行实测并采集山_(2)^(3)亚段泥页岩样品,并通过系统的有机碳含量、全岩矿物组成,主量、微量元素分析测试,对鄂尔多斯盆地东缘山西组山_(2)^(3)亚段海陆过渡相泥页岩沉积期的古气候、水体环境、古生产力及与富有机质泥页岩发育关系进行了研究。结果表明:研究区山西组山_(2)^(3)亚段泥页岩矿物组成中石英和黏土矿物占绝对优势,TOC平均值为2.04%,属于TOC较高的泥页岩;Sr、Sr/Ba、δ^(18)O分析结果揭示山_(2)^(3)亚段水体沉积环境经历了从下至上由咸水—半咸水—淡水的变化;Ce_(anom)、Ni/Co、V/(V+Ni)判别表明山_(2)^(3)亚段主体为贫氧—缺氧的水体环境;CaO/Al_(2)O_(3)*MgO、CIA指数表明山_(2)^(3)亚段沉积时期气温由下至上逐渐降低,风化程度减弱;V/Ni、Mn/Ti及δ^(13)C揭示山_(2)^(3)亚段沉积期水体深度自下而上呈先增大再逐渐减小趋势;P/Al和生物Ba在山_(2)^(3)亚段变化趋势一致,表现为从下至上先增大再减小。山_(2)^(3)亚段泥页岩有机质的富集主要受水体氧化还原条件与陆源碎屑输入的影响。
The study of Carboniferous-Permian marine continental transitional facies shale gas in Ordos Basin mainly focuses on the second member of Shanxi Formation,and Shan_(2)^(3) sub-member is the most abundant layer of organic matter in the second member of Shanxi Formation.Based on the observation and sampling analysis of Chengjiazhuang section in Liulin County,through the organic carbon content,whole rock mineral composition,combined with the analysis and test data of major and trace elements,the paleoclimate,water environment,paleoproductivity and their relationships with the development of organic-rich shale in Shan_(2)^(3) sub-member of Shanxi Formation in the eastern margin of Ordos Basin were studied.The results show that quartz and clay minerals are absolutely dominant in Shan_(2)^(3) shale,and the average TOC is 2.04%.The analytical results of Sr,Sr/Ba and δ^(18)O content show that the sedimentary environment of Shan_(2)^(3) shale experienced the change from saline water to brackish water and then to freshwater from bottom to top.The discrimination of Ceanom,Ni/Co and V/(V+Ni) shows that Shan_(2)^(3) shale was deposited under an oxygen deficient anoxic reduction environment;CaO/Al_(2)O_(3)*MgO and CIA indexes show that the temperature gradually decreases from bottom to top and the weathering degree weakens during the deposition period;The contents of V/Ni,Mn/Ti and δ^(13)C isotopes indicate that the depth of the sedimentary water in the Shan_(2)^(3) sub-member increases first and then gradually becomes shallow.The change trend of P/Al and biological Ba in Shan_(2)^(3) sub-member is consistent,which shows that it increases first and then decreases from bottom to top.The enrichment of organic matter in Shan_(2)^(3) sub-member is mainly affected by water redox conditions and terrestrial debris input.
作者
张雷
赵培华
侯伟
李树新
李星涛
吴陈君
张琴
肖玉峰
刘雯
刘丹
封从军
邱振
ZHANG Lei;ZHAO Peihua;HOU Wei;LI Shuxin;LI Xingtao;WU Chenjun;ZHANG Qin;XIAO Yufeng;LIU Wen;LIU Dan;FENG Congjun;QIU Zhen(Zhonglian CBM State Engineering Research Center Co.,Ltd.,Beijing 100095,China;PetroChina Coalbed Methane Company,Beijing 100028,China;Hubei Key Laboratory of Petroleum Geochemistry and Environment(Yangtze University),Wuhan 430100,China;PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;State Key Laboratory of Continental Dynamics,Northwest University,Xi’an 710069,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第2期181-193,共13页
Natural Gas Geoscience
基金
中国石油勘探开发研究院院级项目“中国典型盆地页岩油气重点层系有机质富集机理研究与主控因素分析”(编号:2021yjcq02)
中国石油“十四五”前瞻性基础性项目“海陆过渡相页岩气成藏条件及勘探前景评价研究”(编号:2021DJ2001)联合资助.
关键词
元素地球化学特征
泥页岩
山西组
沉积环境
鄂尔多斯盆地
Element geochemical characteristics
Mudshale
Shanxi Formation
Sedimentary environment
Ordos Basin
作者简介
张雷(1982-),男,内蒙古人,博士,高级工程师,主要从事煤层气资源评价及勘探开发研究.E-mail:zhanglei2010@petrochina.com.cn;通信作者:张琴(1985-),女,湖北荆门人,博士,高级工程师,主要从事非常规油气地质研究.E-mail:zhangqin2169@petrochina.com.cn.
