摘要
为了分析页岩气储层中黏土矿物特征及其对页岩气勘探、开发的影响,以四川盆地南部及其周缘下志留统龙马溪组黑色富有机质页岩发育层段为主要研究对象,利用X-射线衍射分析,并与大量的薄片和背散射分析资料相结合,较系统地揭示了研究区龙马溪组黏土矿物的发育及分布特征。研究表明：黏土矿物以绿泥石＋伊/蒙混层＋伊利石为主,具有陆源碎屑和次生成因2种类型,主要分布在盆地中心及其边缘地区,具有高伊利石、伊/蒙混层含量,较高绿泥石含量的特点;黏土矿物的类型和含量具有一定的指相意义,平均含量大于50%的地区,主要为深水陆棚沉积,在30%-50%之间的地区通常为浅水陆棚沉积,小于30%的地区为海陆过渡相沉积;龙马溪组沉积时为半干旱—干旱的气候,成岩过程中水介质具有盐度较高、偏碱性,富K＋的特点;成岩演化已达到晚成岩阶段,烃类演化至干气阶段,具备形成页岩气的气源条件;根据黏土矿物对页岩气储集空间的影响,并与有机碳的展布特征相叠合,渝东南地区的綦江—武隆—彭水一带、黔西—滇北地区的雷波—筠连—兴文—仁怀—桐梓近EW向展布的一带,以及研究区西北部的峨边西河地区为页岩气的有利区,位于盆地中心的宜宾—江津—涪陵呈NE—SW向展布的区域,为次级有利区。
In order to investigate the physical characteristics of clay minerals in shale gas reservoir and their influence on the gas exploration and development,black shale from the Lower Silurian Longmaxi Formation in southern Sichuan Basin and its periphery were as studied.Based on X-diffraction analysis,combined with observation of thin sections and backscattered electron images,characteristics of clay minerals and their distribution were revealed.Chlorite＋illite/smectite＋illite is the main assemblage,including transformed and inherited types,which is dominated by illite,illite/smectite mixed layers and chlorite.The type and content of clay minerals have a certain meaning for sedimentary facies,for example,deep shelf facies have an average content of〉50%,transitional facies are of〈30%,and shallow shelf facies is between them.Longmaxi Formation had experienced arid-semiarid climate during sedimentation,burial water medium was saline and alkaline,and enriched in K＋.The diagenetic evolution has reached the late diagenetic stage.In combination with the distribution characteristics of TOC,the area of Qijiang-Wulong-Pengshui in southeast of Chongqing,and Leibo-Junlian-Xingwen-Renhuai-Tongzi in west of Guizhou and north of Yunnan,as well as Xihe county in western Sichuan,are favorable for shale gas.The area of Yibin-Jiangjin-Fuling in Sichuan,is a secondary favorable zone.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2014年第11期1781-1794,共14页
Natural Gas Geoscience
基金
中国石化股份有限公司勘探南方分公司项目
中国岩相古地理编图项目(编号:1212010916060)联合资助
关键词
成因
分布特征
页岩气
黏土矿物
龙马溪组
四川盆地南部及周缘
Genesis
Distribution
Shale gas
Clay mineral
Longmaxi Formation
Southern Sichuan Basin and its periphery
