石油与天然气地质 ›› 2012, Vol. 33 ›› Issue (5): 713-719,729.doi: 10.11743/ogg20120507

• 油气地质 • 上一篇    下一篇

用自生伊利石定年确定鄂尔多斯盆地东北部二叠系油气成藏期次

陈刚1, 徐黎明2, 丁超1, 章辉若2, 李书恒2, 胡延旭1, 黄得顺1, 李楠1, 李岩1   

  1. 1. 西北大学 地质学系, 大陆动力学国家重点实验室, 陕西 西安 710069;
    2. 中国石油 长庆油田分公司, 陕西 西安 710021
  • 收稿日期:2011-07-10 修回日期:2012-07-20 出版日期:2012-10-28 发布日期:2012-11-15
  • 第一作者简介:陈刚(1965-),男,教授、博士生导师,含油气盆地学与油气成藏年代学。
  • 基金项目:

    国家基础研究发展计划项目(2003CB214607);陕西省自然科学基金重点项目(2012JZ5001);教育部高校博士点专项科研基金项目(20116101110006)与留学回国人员择优资助项目。

Authigenic illite dating for the timing of oil-gas accumulation of the Permian reservoirs in northeastern Ordos Basin

Chen Gang1, Xu Liming2, Ding Chao1, Zhang Huiruo2, Li Shuheng2, Hu Yanxu1, Huang Deshun1, Li Nan1, Li Yan1   

  1. 1. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an, Shaanxi 710069, China;
    2. PetroChina Changqing Oilfield Company, Xi’an, Shaanxi 710021, China
  • Received:2011-07-10 Revised:2012-07-20 Online:2012-10-28 Published:2012-11-15

摘要:

运用含油气砂岩自生伊利石K-Ar定年方法,探讨分析了鄂尔多斯盆地东北部上古生界二叠系油气成藏的期次和时间。结果表明,二叠系不同含油气层段均不同程度地经历了与烃源岩两次主生烃作用相应的(175~155 Ma和145~115 Ma)原生油气成藏事件,峰值年龄主要集中在中侏罗世晚期的165 Ma和早白垩世早期的130 Ma。其中,下二叠统油气成藏期以较宽的时域分布(178~110 Ma),中、上二叠统则相对较晚地分布在(160~108 Ma),且上二叠统的起止时限主要集中在(160~125 Ma);二叠系样品年龄的空间分布总体呈现其油气成藏过程具有自南(178~122 Ma)向北(131~108 Ma)年龄逐渐减小的渐次运聚成藏特点。因此,包括上二叠统在内的二叠系不同层段均不同程度地经历了早-中侏罗世和早白垩世的两期原生油气成藏作用,上二叠统气藏现今显示的次生成藏特点很可能是在原生油气成藏基础上后期叠加改造或次生成藏的结果。

关键词: 二叠系, 油气成藏, 自生伊利石测年, 鄂尔多斯盆地东北部

Abstract:

The K-Ar dating method with authigenic illite(AI)is applied to oil-gas-bearing sandstone core-samples to determine the stages and timing of the Permian oil-gas accumulation in northeastern Ordos Basin.Results show that the Permian oil-gas-bearing intervals all experienced two events of original oil-gas accumulation during the periods of 175-155 Ma and 145-115 Ma,respectively corresponding to two age-peaks at 165 Ma of the Middle Jurassic and 130 Ma of the Early Cretaceous in coincidence with the generation stages of the permian hydrocarbon source rocks in the Early and Middle Mesozoic.Specifically,oil-gas accumulation in the Lower Permian features in a relatively wide time range from 178 Ma to 110 Ma,while that in the Middle and Upper Permian is characterized by a narrow time range from 160 Ma to 108 Ma.The AI dating of(160-125)Ma of the Upper Permian samples indicates a relatively earlier ending time of its oil-gas accumulation.Also,the spatial and temporal distribution of the AI ages shows that the sequence of oil-gas migration to accumulation in the Permian is mainly from south(178-122 Ma)to north(131-108 Ma).Accordingly,it could be speculated that reservoirs in the Permian almost unanimously experienced two stages of original oil-gas accumulation during the Early to Middle Jurassic and the Early Cretaceous;and the current secondary accumulation features of the Upper Permian reservoirs should be mainly caused by the later reformation and adjustment of the original oil-gas accumulation during the Late Mesozoic to Cenozoic uplifting of the basin.

Key words: Permian, oil-gas accumulation, authigenic illite dating, northeastern Ordos Basin

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