石油与天然气地质 ›› 2010, Vol. 31 ›› Issue (5): 610-619.doi: 10.11743/ogg20100511

• 石油与天然气地质 • 上一篇    下一篇

川西地区中、晚三叠世岩相古地理演化及勘探意义

  

  1. 中国石油化工股份有限公司南方勘探开发分公司，四川成都610041
  • 出版日期:2010-10-28 发布日期:2010-12-10
  • 作者简介:郭旭升（1965—），男，教授级高级工程师，石油地质综合研究和勘探管理。
  • 基金资助:

    国家油气重大专项（2008CX05005-003）。

L itho-paleogeographic evolution in theM iddleˉLate Triassic in western Sichuan Province and its significance for petroleum exploration

  • Online:2010-10-28 Published:2010-12-10

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摘要：

川西地区中、晚三叠世经历了由海相经海-陆过渡相到陆相的盆地转换过程，亦是区内烃源岩与储集岩发育的主要时期。依据钻井、露头资料，结合区域地质特征，详细研究了其岩相古地理特征及演化史。雷口坡至马鞍塘沉积期由西向东为深水盆地到台地边缘、台地的古地理格局，台地边缘高能滩（及礁）相和台内滩相具有良好的勘探前景;须二至须三期主要发育海-陆过渡环境的三角洲沉积，三角洲平原分流河道、三角洲前缘水下分流河道和河口砂坝等微相是储集层发育的有利相带，为近年主要勘探目的层系;须三末期的安县运动是川西地区海、陆彻底转换的关键时期，龙门山全面褶皱成山，整个四川盆地转变为陆相沉积环境，川西地区须四至须五期表现出冲积扇、湖泊三角洲和湖泊体系占主导的沉积格局。系统研究中、晚三叠世川西地区的岩相古地理格局与演化过程，可以进一步梳理川西地区勘探、评价思路，分析勘探战略，明确主要的勘探领域及有利的勘探方向，进而指导下一步油气勘探实践。

关键词: 勘探领域, 勘探意义, 古地理演化, 中、晚三叠世, 川西地区

Abstract:

During the Middle and Late Triassic，western Sichuan Province experienced a transform ing process from marine facies，transitional facies，to continental facies.Most source rocks and reservoir rocks developed during that period.Based on drilling and outcrop data and regional geological characteristics，this paper exam ines its lithoˉpaleogeographic features and evolution.During the deposition of the Leikoupo Formation to theMa’an-tang Formation，from west to east，the sedimentary environmentwas deepwater basin，platform margin and platˉform.The high energy platform edge shoal/reef facies and intraplatform shoal facies are favorable targets for petroleum exploration.During the deposition of the2 nd member and the3 rd member of the Xujiahe Formation，itwas a marineˉterrestrial transitional setting with delta deposits.Several m icrofacies，such as delta plain distributary channels，delta front subaqueous distributary channels and mouth bars，are favorable for the development of reservoirs.They have been the main exploration targets in recent years.The AnxianMovement，which occurred at the end ofdeposition of the3 rd member of the Xujiahe Formation，is a key point for the transition ofmarine facies to terrestrial facies in western Sichuan Province.At that time，the Longmen Mountain area was folded to mountains completely and the whole Sichuan Basin was turned into a continental sedimentary environment.During the deposition of the4 th member and the5 th member of the Xujiahe Formation，western Sichuan Provincewas dom inated by fluvial fans，lacustrine deltas and lake systems.By systematically exam ining theMiddle-Late Triassic litho-paleogeographic framework and evolution in western Sichuan Province，we can further check our exploˉration and appraisal approaches，analyze exploration strategies and figure outmain exploration targets，so as to guide exploration in future.

Key words: exploration target, significance for petroleum exploration, paleogeographic evolution, MiddleˉLate Triassic, western Sichuan Province