石油与天然气地质2025，Vol.46Issue(6)：1892-1906,15.DOI:10.11743/ogg20250610
川北地区下寒武统筇竹寺组页岩岩相类型及分布特征
Lithofacies types of shales and their distribution in the lower Cambrian Qiongzhusi Formation,northern Sichuan Basin
摘要
Abstract
The identification and classification of the lithofacies types of shales are essential for assessing the potential for shale gas exploration and exploitation and for selecting the optimal shale gas sweet spot intervals.Based on observations of outcrops,cores,and thin sections,as well as whole-rock X-ray diffraction(XRD)mineralogy and total organic carbon(TOC)content determination,we investigate the lithofacies types of shales and their distribution characteristics in the Qiongzhusi Formation,northern Sichuan Basin.The developmental patterns of favorable lithofacies assemblages from taphrogenic troughs to intra-platform depressions are identified,and the sedimentary patterns of shales in the 1st and 2nd members of the Qiongzhusi Formation(also referred to as the Qiong 1 and Qiong 2 members,respectively)are established.The results indicate that a classification scheme based on TOC content and the respective contents of quartz+feldspar,clay minerals,and carbonate minerals allows the shales of the Lower Cambrian Qiongzhusi Formation to be classified into 13 lithofacies types,which are dominated by highly organic clay-bearing felsic shales,organic-rich clay-bearing felsic shales,moderately organic clay-bearing felsic shales,and highly organic felsic shales.Shale intervals with a TOC content of 1.0%or higher in the Qiongzhusi Formation primarily contain five favorable lithofacies assemblages:(1)highly organic to organic-rich clay-bearing felsic shales;(2)highly organic to organic-rich felsic shales;(3)moderately to highly organic clay-bearing felsic shales;(4)moderately to highly organic felsic shales;and(5)moderately to highly organic clay-bearing felsic shales and felsic shales.The distribution characteristics of these lithofacies associations are systematically documented for 1st and 2st members of the Qiongzhushi Formation.The research findings can provide a valuable basis for decision-making in both the assessment of target area selection and exploratory well emplacement for the exploration and exploitation of shales in the Qiongzhusi Formation in northern Sichuan Basin.关键词
岩相/岩相组合/页岩/筇竹寺组/下寒武统/四川盆地Key words
lithofacies/lithofacies assemblage/shale/Qiongzhusi Formation/Lower Cambrian/Sichuan Basin分类
能源科技引用本文复制引用
高波,戎佳,张明何,刘自亮,燕继红,杜伟,李王鹏..川北地区下寒武统筇竹寺组页岩岩相类型及分布特征[J].石油与天然气地质,2025,46(6):1892-1906,15.基金项目
国家自然科学基金项目(42272183) （42272183）
中国石化科技部项目(P25144). （P25144）
