石油与天然气地质 ›› 2017, Vol. 38 ›› Issue (3): 534-542.doi: 10.11743/ogg20170313

• 油气地质 • 上一篇    下一篇

碳酸盐岩缝合线与基质的排烃效应——以川东地区石炭系和奥陶系碳酸盐岩为例

王轩, 高岗, 李佳烨, 葛黛薇, 张维维   

  1. 中国石油大学(北京) 油气资源与探测国家重点实验室, 北京 102249
  • 收稿日期:2016-04-12 修回日期:2017-04-20 出版日期:2017-06-28 发布日期:2017-07-10
  • 通讯作者: 高岗(1966-),男,博士、副教授,油气勘探与开发。E-mail:gaogang2819@sina.com。 E-mail:gaogang2819@sina.com
  • 作者简介:王轩(1992-),男,硕士研究生,石油地质研究。E-mail:1528159409@qq.com。
  • 基金资助:
    国家自然科学基金项目(41372142)。

Hydrocarbon expulsion of stylolite and matrix in carbonate rocks:A case study from the Ordovician and Carboniferous carbonate rocks in Eastern Sichuan Basin

Wang Xuan, Gao Gang, Li Jiaye, Ge Daiwei, Zhang Weiwei   

  1. State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum(Beijing), Beijing 102249, China
  • Received:2016-04-12 Revised:2017-04-20 Online:2017-06-28 Published:2017-07-10

摘要: 为了探究碳酸盐岩缝合线与基质的排烃效应及其物质组成的差异,采集了四川盆地东部大池干构造带座3、池53、五科1等取心井含缝合线的石炭系和奥陶系碳酸盐岩岩心样品,进行了缝合线与基质的岩心与铸体薄片观察以及全岩X-射线衍射矿物成分含量、有机碳含量、热解(Rock-Eval)、可溶有机质抽提、族组分分离与定量等实验测试。实验分析表明,缝合线比基质的物质组成有较大差异,这主要与压溶作用有极为密切的关系。由于碳酸盐矿物的压溶作用,缝合线比基质含有更多的白云石、黄铁矿、有机质等不溶物质,矿物颗粒主要呈基底胶结、杂基支撑,基质中的矿物颗粒之间主要呈线状、凹凸状紧密接触。这种矿物组成和结构特征使得缝合线比基质有相对更好的孔渗性,可以成为地质历史时期中碳酸盐岩内部流体排出的重要通道,所以,缝合线的排烃效应比基质明显。对于含有缝合线的低有机质丰度碳酸盐岩来说,缝合线有机质可以作为碳酸盐岩生烃的重要补充。此外,缝合线中较多的可溶有机质对热解参数有一定影响。

关键词: 缝合线, 基质, 有机地球化学, 排烃效应, 碳酸盐岩, 四川盆地

Abstract: This paper discusses the differences of hydrocarbon expulsion and compositions between stylolite and matrix in carbonate rocks.Samples were taken from the Ordovician and Carboniferous carbonate rock cores containing stylolites of Wells Zuo 3,Chi 53 and Wuke 1 in the Dachigan Structure Belt of the Eastern Sichuan Basin.The stylolite and matrix were studied through observation of core and cast thin sections and various tests such as whole rock X-Ray diffraction for mineral components and TOC content,Rock-Eval pyrolysis,solvent extraction and fractionation of extract and so on.The results indicate that there is a relatively large compositional difference between stylolite and matrix in carbonate rocks,and this is intimately related to pressure solution of carbonate mineral.Because of pressure solution,the stylolite contains more indissoluble materials such as dolomite,pyrite,and organic matter than the matrix.The mineral grains in stylolies mainly display basal cementation and matrix-supported fabric.While the mineral grains in the matrix mainly represent linear contact and close contact in concave and convex shapes.This makes stylolite to have better physical properties compared with the matrix,thus acting as important passages for expulsion of fluids in carbonate rocks in geological history.Therefore,the hydrocarbon expulsion effect of stylolite is more evident than that of the matrix.For the stylolite-bearing carbonate rocks with low organic abundance,the organic matter in the stylolite can be a prominent supplement of hydrocarbon generation in carbonate source rocks.In addition,the soluble organic matters relatively abundant in the stylolite have certain effects on Rock-Eval pyrolysis parameters.

Key words: stylolite, matrix, organic geochemistry, hydrocarbon expulsion effect, carbonate rock, Sichuan Basin

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