三塘湖盆地上石炭统哈尔加乌组烃源岩有机地球化学特征及意义  

Organic Geochemical Characteristics and Geological Significance of Source Rocks in Late Carboniferous Harjiawu Formation of Santanghu Basin

作　　者：周宁超[1,2] 柳益群[1] 南云[1] 周鹏[1] 焦鑫[1] 米董哲[1] 

机构地区：[1]大陆动力学国家重点实验室,西北大学地质学系,陕西西安710069 [2]中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《天然气地球科学》2014年第12期2014-2024,共11页Natural Gas Geoscience

基　　金：国家自然科学基金面上项目(编号:41272116);西北大学大陆动力学国家重点实验室重点基金(编号:BJ08133-3);教育部科技发展中心高等学校博导基金(编号:20126101110020)联合资助

摘　　要：新疆三塘湖盆地上石炭统哈尔加乌组为一套中基性火山岩、火山碎屑岩夹沉积岩组合,沉积岩中发育多层厚度不等的烃源岩。采用岩石热解与饱和烃GC—MS分析对哈尔加乌组烃源岩进行了研究。结果表明：该套烃源岩有机质丰度高,有机质类型存在Ⅲ型和Ⅰ型2种端源干酪根及两者按不同比例的混合类型,有机质热演化主体已达到成熟阶段;烃源岩中较高的Pr/Ph值（1.1~3.01）、低的伽马蜡烷指数（0.047~0.158）及三环二萜烷分布特征表明沉积水体具淡水弱氧化—弱还原性质,这些指标与低的C31R/C30藿烷（0.186~0.310）、低的C22/C21三环萜烷（0.164~0.260）和较高的C24/C23三环萜烷（0.472~0.684）均为湖相沉积环境提供了有机地球化学方面证据;正构烷烃ΣC21^-/ΣC22^＋值（0.54~2.47）、规则甾烷分布规律（C29〉C27〉C28和C29〉C28〉C27）及甾烷/藿烷（0.06~0.20）等指标均显示有机母质输入既有陆生高等植物,同时也存在大量细菌与藻类等水生生物。The Upper Carboniferous Harjiawu Formation in Santanghu Basin occurs as a set of intermediate basic volcanics,pyroclastic rock and sedimentary rocks which develop many layers of source rock with different thicknesses.The results of Rock-Eval and saturated hydrocarbon GC-MS reveal that the organic matter abundance of source rocks is higher in Harjiawu Formation.The type of organic matter include typeⅢ,type I and the mixture of the both.The degree of thermal evolution of most samples has achieved mature stage.The higher values of Pr/Ph ratios（1.1-3.01）,low values of G/C30hopane（0.047-0.158）,and the tricyclic terpanes distribution indicate that the water environments are weak suboxic-weak and low saline during source rock deposition.Low C31R/C30 hopane ratios（0.186-0.310）,very low C22/C21ratios（0.164-0.260）,higher C24/C23 tricyclic terpane ratios（0.472-0.684）are consistent with the source rocks being deposited in a lacustrine environment.∑C21^-/∑C22^＋,regular sterane distribution（C29〉C27〉C28and C29〉C28〉C27）and sterane/hopane ratios（0.06-0.20）point out that the biological sources of organic matternot only have higher plant,but also have a mass of bacteria and algae.

关 键 词：三塘湖盆地 哈尔加乌组 烃源岩 有机地球化学 

分 类 号：TE122.11[石油与天然气工程—油气勘探]