摘要
本文关注四川盆地龙马溪组和自流井组大安寨段两个页岩气代表层段,以涪陵页岩气田龙马溪组和元坝、涪陵自流井组大安寨段比较系统的实验分析资料为基础,从页岩储层的岩性、物性、电性及含气性、有机地球化学特性、脆性等"六性"对比的角度,对海相和湖相页岩气形成基本条件、富集机理和潜力层段进行分析和讨论,认为有机孔隙的发育程度是造成其含气性差异的主要原因,受TOC含量、热演化程度和有机质类型的影响,海相页岩有机质孔隙更加发育。两套页岩层系都具有较好的勘探前景,发育条带状或纹层状灰岩的浅湖-半深湖相富有机质泥页岩是湖相页岩气勘探的有利相带;龙马溪组底部深水陆棚含骨针放射虫笔石页岩岩相是龙马溪组勘探最有利的页岩岩相,另外富含有机质的浅水陆棚相带泥页岩发育的区域、保存条件受到一定程度破坏但吸附气含量仍较高的区域同样具有一定勘探潜力。
This article is dedicated to two shale gas intervals such as Longmaxi Formation and Da＇anzhai Section of Ziliujing Formation in the Sichuan Basin.In this study we analyzed and examined the basic conditions concerning the formation of marine and lacustrine shale gas,accumulation mechanisms and potential intervals,based on systematic experimental analysis of Longmaxi Formation in the Fuling Shale Gas Field and Da＇anzhai Section of Ziliujing Formation in Yuanba and Fuling areas and also based on the comparisons between six properties of shale reservoirs such as lithologies,geophysical properties,electric properties,shale gas contents,geochemical properties and brittle properties.It is considered that the differences between organic pores developed in marine and lacustrine shales are the main reasons for great differences in gas contents.Both marine and lacustrine shales have remarkable exploration prospects.Due to the differences among TOC,Ro and organic matter type,the organic pores develop better in marine shales.The intervals of organic-rich mudstones or shales with streak or stripe limestones developed in shallow-semi-deep lacutrine are favorable facies belts for shale gas exploration.The lithofacies of grapholite shales with spicules and radiolarians deposited in deep shelf at the bottom of Longmaxi Formation are the most favorable for shale gas exploration.Furthermore,organic-rich mudstones or shales are developed in shallow shelf,though the protecting conditions are destructed to a certain degree,the areas with high adsorbed gas still have potentials for shale gas exploration.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2016年第2期18-28,共11页
Earth Science Frontiers
基金
中国石油化工集团公司重大专项"四川盆地周缘下组合页岩气形成条件与有利区带评价"(P12001)
关键词
页岩气
富集机理
有机质孔隙
龙马溪组
大安寨段
四川盆地
shale gas
accumulation mechanism
organic pores
Longmaxi Formation
Da＇anzhai Section
Sichuan Basin
