火山灰沉积与页岩有机质富集关系探讨——以五峰组—龙马溪组含气页岩为例  

Discussion of the Relationship between Volcanic Ash Layers and Organic Enrichment of Black Shale: A case study of the WufengLongmaxi gas shales in the Sichuan Basin

作　　者：邱振[1,2] 卢斌 陈振宏[1,2] 张蓉 董大忠[1,2] 王红岩 邱军利[4,5] QIU Zhen;LU Bin;CHEN ZhenHong;ZHANG Rong;DONG DaZhong;WANG HongYan;QIU JunLi(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;National Energy Shale Gas R&D(Experiment)Center,Langfang,Hebei 065007,China;Research Institute of Petroleum Exploration and Development,PetroChina Xinjiang Oilfield Company,Karamay,Xinjiang 834000,China;Northwest Institute of Eco⁃Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Key Laboratory of Petroleum Resources,Gansu Province,Lanzhou 730000,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]国家能源页岩气研发(实验)中心,河北廊坊065007 [3]中国石油新疆油田分公司勘探开发研究院,新疆克拉玛依834000 [4]中国科学院西北生态环境资源研究院,兰州730000 [5]甘肃省油气资源研究重点实验室,兰州730000

出　　处：《沉积学报》2019年第6期1296-1308,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目（41602119）;中国石油科学研究与技术开发项目（2016B-0302-01,YJXK2019-16)~~

摘　　要：现代火山活动喷发形成的火山灰沉降到海水中能够提高海洋表层生产力、促进浮游生物繁盛,有利于有机质形成与富集沉积。而地质历史时期火山灰(斑脱岩)沉积与有机质富集关系研究相对较少,且存在着争议。以我国华南地区奥陶纪志留纪转折期五峰组龙马溪组页岩为例,开展含火山灰页岩层段与正常沉积的页岩层段的TOC含量、古生产力、氧化还原条件等对比分析,以探讨两者之间关系。研究结果初步表明:火山灰对高生产力背景的海洋区域影响相对较弱,对其有机质富集的促进作用不明显,而沉积水体氧化还原条件(富氧贫氧缺氧变化)与有机质含量关系密切,是这一时期有机质富集的主控因素。由于火山活动对沉积环境影响是十分复杂的过程,未来需要利用地质、地球化学等多种测试手段,开展更高分辨率(如厘米级、毫米级尺度)综合对比研究,精细解剖火山活动对有机质形成及富集作用的影响。火山活动相关的沉积事件是非常规油气沉积学重要研究内容之一,厘定它与页岩有机质富集关系,对我国页岩油气等非常规油气勘探开发具有重要意义。Previous studies have shown that the deposition of volcanic ash from modern volcanic activity into seawa ter can improve marine surface productivity,promote the flourishing of plankton,and facilitate the formation and en richment of organic matter.However,there are few studies on the relationship between volcanic ash deposition and or ganic matter enrichment in geological history,which has always been controversial.A large number of volcanic ash layers developed in the gas shales of the Wufeng Longmaxi Formation during the Ordovician Silurian transition in South China,providing a typical strata system for this research.Total organic carbon(TOC)content,paleo produc tivity,and redox conditions of the shale horizons,including volcanic ash layers and no volcanic ash layers,were com paratively analyzed.The results show that the volcanic ash deposition during the Ordovician Silurian transition had a relatively weak effect on marine productivity and did not significantly promote the accumulation of organic matter.The redox condition has a close relationship with TOC content,suggesting it could be the main controlling factor.The in fluence of volcanic activity on the sedimentary environment is a very complicated process.Therefore,in the future,comprehensive studies with higher resolution(such as centimeter scale and millimeter scale)should be carried out by using geological,geochemical,and other testing methods to finely analyze the impact of volcanic activity on the formation and enrichment of organic matter.Sediments related to volcanic activity are one of the research targets of un conventional petroleum sedimentology,and the determination of the relationship between them and organic enrich ment in shale would have an important role in the exploration and development of unconventional petroleum,such as shale oil and gas.

关 键 词：非常规油气沉积学 有机质富集 斑脱岩 页岩气 四川盆地 

分 类 号：P618.13[天文地球—矿床学] P588.2[天文地球—地质学]