石油与天然气地质 ›› 2017, Vol. 38 ›› Issue (2): 311-322.doi: 10.11743/ogg20170211

• 油气地质 • 上一篇    下一篇

准噶尔盆地玛湖凹陷二叠系烃源岩三环萜烷分布样式及影响因素

陈哲龙1,2, 柳广弟1, 卫延召2, 高岗1, 任江玲3, 杨帆2, 马万云3   

  1. 1. 中国石油大学(北京) 地球科学学院, 北京 102249;
    2. 中国石油 勘探开发研究院, 北京 100083;
    3. 中国石油 新疆油田公司 实验检测研究院, 新疆 克拉玛依 834000
  • 收稿日期:2015-07-12 修回日期:2017-02-20 出版日期:2017-04-28 发布日期:2017-05-04
  • 作者简介:陈哲龙(1988-),男,博士、工程师,油气地球化学与成藏。E-mail:chenzl@petrochina.com.cn。
  • 基金资助:
    国家科技重大专项(2016ZX05001005);中石油新疆油田公司课题(2014-C4023)。

Distribution pattern of tricyclic terpanes and its influencing factors in the Permian source rocks from Mahu Depression in the Junggar Basin

Chen Zhelong1,2, Liu Guangdi1, Wei Yanzhao2, Gao Gang1, Ren Jiangling3, Yang Fan2, Ma Wanyun3   

  1. 1. College of Geosciences, China University of Petroleum, Beijing 102249, China;
    2. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China;
    3. Research Institute of Experiment and Testing, PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 843000, China
  • Received:2015-07-12 Revised:2017-02-20 Online:2017-04-28 Published:2017-05-04

摘要: 准噶尔盆地西北缘原油及烃源岩中生物标志物以高丰度的三环萜烷系列为典型特征,其分布样式的差异一直被当作研究本区原油成因类型及油-源对比的典型指标。通过对烃源岩样品的系统地球化学分析,认为本区风城组源岩(P1f)主要以三环萜烷(C20,C21,C23)呈“上升型”为特征,泥质岩类与碳酸盐岩类相比C24,C25三环萜烷含量较高;下乌尔禾组(P2w)源岩和佳木河组(P1j)源岩样品三环萜均呈“下降型”分布特征。通过对源岩镜下进行观察和加水热模拟实验等方法,分别探讨了沉积环境与母质类型、成熟度及排烃作用对三环萜分布样式的影响,认为P1f和P2w源岩中三环萜烷的分布主要受控于沉积环境和母质类型的原生差异。P1f源岩有机质多源于本地沉积的藻类及细菌,沉积环境属于蒸发、还原的咸化湖沉积;P2w源岩中外来有机质含量相对较多,沉积环境属于淡水还原环境。P1j源岩整体热演化程度较高,有机质炭化作用强烈;埋藏成熟演化在有机质处于成熟-高熟阶段内对三环萜烷分布样式影响不大,若达到过熟阶段则会造成低碳数三环萜烷(C20,C21)含量增加;排烃作用对三环萜烷影响相对较小,不改变其分布样式。

关键词: 三环萜烷, 生物标志物, 加水热模拟, 二叠系, 烃源岩, 玛湖凹陷, 准噶尔盆地

Abstract: Biomarkers extracted from the crude oil and source rock samples obtained from the northwestern margin of Junggar Basin are characterized by high abundance of tricyclic terpanes (TTs).The distribution pattern of TTs has been used to distinguish oil families and to conduct oil-source correlations.Comprehensive geochemical analyses of source rock samples reveal that different distribution patterns of TTs correspond to different sets of source rocks,i.e.the Fengcheng Formation(P1f) features in "Going Up" of C20,C21 and C23 TTs,with higher amounts of C24 and C25 TTs for mudstones in comparison with carbonate rocks;the Lower Wuerhe Formation(P2w)and the Jiamuhe Formation(P1j)are characterized by "Going Down" of C20,C21 and C23 TTs.The influences of sedimentary environment,kerogen type,maturity and hydrocarbon expulsion on distribution of TTs were studied through microscopic observation of thin sections and hydrous pyrolysis simulation.We concluded that the TTs distribution patterns of P1f and P2w are mainly controlled by sedimentary environment and kerogen type.The organic matters of the P1f source rocks were mainly derived from autochthonous algae or bacteria and were deposited in an evaporative reducing salt lake,while allochthonous organic matters were relatively abundant in the P2w and were deposited in a semi-reducing fresh lacustrine environment.The P1j source rocks are currently over-mature and have experienced intense carbonization.Burial thermal evolution has limited impacts on the distribution patterns of TTs during mature and high-mature stage,but can result in the increase of low carbon number terpanes during over-mature stage.Hydrocarbon expulsion has limited influences on the TTs distribution pattern.

Key words: tricyclic terpanes, biomarkers, hydrou pyrolysis, Permian source rock, Mahu Depression, Junggar Basin

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