四川盆地五峰组—龙马溪组含气页岩中石英成因研究  

The genesis of quartz in Wufeng-Longmaxi gas shales,Sichuan Basin

作　　者：赵建华[1] 金之钧[2] 金振奎[1] 温馨[1] 耿一凯 颜彩娜[3] 

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石化石油勘探开发研究院,北京100083 [3]中国地质大学(北京)能源学院,北京100083

出　　处：《天然气地球科学》2016年第2期377-386,共10页Natural Gas Geoscience

基　　金：中国石化科技攻关项目"川东地区龙马溪组页岩气富集规律与分布预测"(编号:G5800-14-ZS-KJB158)资助

摘　　要：为了分析含气页岩中石英的成因类型及其对页岩储层质量的影响,以四川盆地五峰组—龙马溪组含气页岩层段为主要研究对象,利用X-射线衍射分析、扫描电镜、阴极发光、能谱分析及主量元素测试等手段,识别出陆源石英和成岩过程中形成的石英。陆源石英阴极光下表现为强发光,单色阴极发光光谱一般有2个峰值,主峰出现在620~650nm处,次峰出现在420~450nm处;成岩过程中形成的石英单色阴极发光特征为弱发光—不发光,光谱通常在波长620nm附近出现峰值。成岩过程中形成的石英包括以隐晶、微晶及微晶聚集体的形式出现,呈不规则状的生物成因石英;以及嵌入在黏土基质中微米级颗粒,呈短链状、小晶簇状聚集,或以板片状、小晶片状形式存在的黏土矿物转化过程中形成的石英。TOC值与石英含量呈明显的正相关关系,说明高石英含量且富含生物成因石英页岩沉积时,有利于有机质的富集,并且页岩储层脆性高,可压裂性好。In order to analyze the genesis of quartz in gas shale and its effect on the reservoir quality,shales of the Wufeng-Longmaxi Formations in the southeastern part of Sichuan Basin are taken as a research object.Based on X-diffraction analysis,scanning electron microscope combined with cathode luminescence（CL）,energy spectrum analysis and major elements test,detrital quartz and diagenetic quartz were identified.Monochromatic CL of diagenetic quartz with less intensity,typically displayed characteristic CL-peak close to wavelengths of about 620 nm.Biogenic silica occurs as irregular shape with relatively large aggregates of crypto-or microcrystalline.The micro-sized quartz crystals sourced from the smectite to illite reaction occur as discrete grains,small clusters,thin sheet or micro sheet within the clay matrix.TOC and quartz content have positive correlation,which indicated high quartz content shales enriched in biogenic silica were beneficial to the enrichment of organic matter and reservoir fracturing with a high brittleness.

关 键 词：石英成因 储层质量 陆源石英 生物成因石英 

分 类 号：TE122.2[石油与天然气工程—油气勘探]