鄂西地区二叠系孤峰组—大隆组沉积演化及其页岩气地质意义  

SEDIMENTARY EVOLUTION CHARACTERISTICS OF PERMIAN GUFENG FORMATION-DALONG FORMATION IN WESTERN HUBEI PROVINCE AND ITS GEOLOGICAL SIGNIFICANCE FOR THE GEOLOGICAL SURVEY OF SHALE GAS

作　　者：翟常博 牟传龙[2] 梁薇[2] 郑斌嵩 昝博文 Zhai Changbo;Mou Chuanlong;Liang Wei;Zheng Binsong;Zhan Bowen(Sinopec Petroleum Exploration and Production Research Institute,Beijing 100083,China;Chengdu Center of China Geological Survey,Chengdu,Sichuan 610081,China)

机构地区：[1]中国石油化工股份有限公司石油勘探开发研究院,北京100083 [2]中国地质调查局成都地质调查中心,四川成都610081

出　　处：《矿物岩石》2021年第4期114-124,共11页Mineralogy and Petrology

基　　金：“四川盆地多旋回沉积构造演化于油气勘探潜力”(编号:P20059-7)。

摘　　要：鄂西地区二叠系发育孤峰组、吴家坪组和大隆组三套黑色岩系,为页岩气探勘新主力层系,其沉积背景、沉积环境及时空分布却不尽一致。本次在前人的研究基础上,通过野外剖面和最新的钻井资料综合分析,对该地区二叠系孤峰组—大隆组沉积演化进行了深入解剖,并通过岩相古地理图约束了富有机质页岩的空间分布特征,旨在为鄂西地区二叠系页岩气地质调查和选区评价提供基础资料。研究认为,鄂西地区孤峰组主要发育盆地相碳质硅质泥岩,局部地区发育外缓坡相富有机质泥质灰岩;吴家坪组炭山湾段主要发育潮坪相泥质粉砂岩夹煤层,并在利川地区发育陆棚相的碳质硅质泥岩;吴家坪组灰岩段主要为内缓坡相的生屑泥晶灰岩。大隆组主要发育盆地相碳质硅质泥岩,其次为外缓坡相富有机质泥质灰岩,利川见天坝可见发育内缓坡边缘点礁。综合前人对各层位研究的页岩气参数认为,鄂西地区孤峰组和大隆组具有有机质含量高(>2%)、厚度大(>20 m)、脆性矿物含量高(>60%)等形成页岩气的基本地质条件,深水盆地相为有利相带;吴家坪组炭山湾段潮坪相的黑色泥岩较薄(<10 m),连续性差,但利川地区吴家坪组炭山湾段深水陆棚相黑色泥岩厚度较大(~30 m),为潜在的页岩气勘探区域。Permian Gufeng Formation,Wujiaping Formation and Dalong Formation in western Hubei area are three black rock series with inconsistent sedimentary background,sedimentary environment and temporal and spatial distribution.Nevertheless,they are the new main shale gas exploration strata.In this paper,on the basis of previous research and combined with the field profile and the latest drilling data,a synthetic analysis of the sedimentary evolution of regional Permian Gufeng-Dalong Formation has carried out.Through the lithofacies paleogeographic analysis,the spatial distribution characteristics of the rich organic shale are constrained,which provides data of geology survey and selection evaluation in the area.It shows that the Gufeng Formation in western Hubei area mainly developed basin facies carbonaceous siliceous mudstone,and the outer gentle slope facies organic-rich argillaceous limestone developed locally.In the Tanshanwan Member of Wujiaping Formation,there are mainly tidal flat facies argillaceous siltstone interbedded with coal seam,and shelf facies carbonaceous siliceous mudstone in Lichuan area.The limestone member of Wujiaping Formation is mainly bioclastic micritic limestone of inner gentle slope facies.The Dalong Formation is mainly composed of carbonaceous siliceous mudstone in basin facies,followed by organic-rich argillaceous limestone in outer gentle slope facies,and point reef on inner gentle slope edge in Jiantianba,Lichuan.Based on previous studies on shale gas parameters,it is concluded that Gufeng Formation and Dalong Formation have the basic geological conditions for shale gas formation,such as high organic matter content(>2%),high thickness(>20 m)and high brittle mineral content(>60%),and favorable facies belt of deepwater basin facies.The black mudstone of tidal flat facies in Tanshanwan Member of Wujiaping Formation is thin(<10 m)with poor continuity.However,the deepwater shelf facies Tanshanwan Member black mudstone of Wujiaping Formation in the Lichuan area is thick(~30 m),which is a poten

关 键 词：页岩气 二叠系 岩相古地理 鄂西地区 

分 类 号：P579[天文地球—矿物学]