石油与天然气地质 ›› 2011, Vol. 32 ›› Issue (4): 551-559.doi: 10.11743/ogg20110408

• 石油与天然气地质 • 上一篇    下一篇

川西坳陷中段下三叠统碳酸盐岩储层成岩作用与机理

  

  • 出版日期:2011-08-28 发布日期:2011-09-26

Diagenesis and forming mechanism of the Lower Triassic carbonate reservoirs in the middle part of the western Sichuan Depression

  • Online:2011-08-28 Published:2011-09-26

PDF (PC)

900

被引次数

10

摘要：

摘要：通过川西坳陷中段野外露头资料、岩心样品微观资料，结合部分样品的物性、微量元素、碳氧同位素分析测试结果，对川西坳陷下三叠统飞仙关组、嘉陵江组碳酸盐岩储层特征、成岩作用及形成机理进行了研究。结果表明，在川西坳陷中段的下三叠统中，局部层段发育颗粒滩型储层，但总体以中、低孔—低渗储层为主，鲕粒白云岩、鲕粒灰岩及残余鲕粒砂屑结构的粉细晶白云岩为主要的储集岩。自东北向西南，飞仙关组颗粒碳酸盐岩成岩作用差异明显，由海底成岩环境胶结作用向埋藏成岩环境的溶蚀、胶结作用变化；嘉陵江组成岩作用以埋藏成岩环境为主。综合研究认为，溶蚀作用和白云岩化作用是控制颗粒滩相储层发育的关键因素。岩石学特征以及地球化学特征显示，川西坳陷中段飞仙关组、嘉陵江组部分鲕粒、砂屑白云岩化特征，主要与埋藏白云岩化有关；埋藏溶蚀应为盆地卤水的混合、冷却作用的结果。

关键词: 关键词：储层特征, 成岩作用, 飞仙关组, 嘉陵江组, 川西坳陷

Abstract:

Abstract: This paper studies the characteristics, diagenesis and forming mechanism of the carbonate reservoirs in the Lower Triassic Feixianguan and Jialingjiang formations in the middle part of the western Sichuan Depression based on the outcrop observation and microscopic analysis of core samples, and in combination with the test results of physical property, trace element, and carbon and oxygen isotope analysis of some samples. The results show that grain bank reservoirs are developed in some intervals of the Lower Triassic and they are dominated by mid-lowporosity and lowpermeability reservoirs. The reservoir lithologies are dominated by oolitic dolomite, oolitic limestone, and micritic dolomite with residual oolitic psammitic texture. Diagenesis of the grainy carbonates in the Feixianguan Formation varies a lot from northeast to southwest, changing from cementation in submarine diagenetic environment to dissolution and cementation in burial diagenetic environment. The Jialingjiang Formation is dominated by diagenesis in burial environment. Comprehensive study shows that dissolution and dolomitization are the key factors that control the development of grainbank reservoirs. Petrological and geochemical characteristics indicate that some oolitic dolomite and dolorenite of the Feixianguan and Jialingjiang formations are the products of burial dolomitization, and that burial dissolution might be caused by the mixing and cooling of basin brine.