天然气工业2017，Vol.37Issue(4)：21-26,6.DOI:10.3787/j.issn.1000-0976.2017.04.003
上扬子地区下寒武统黑色页岩矿物组成特征及其油气勘探意义
Mineral composition of the Lower Cambrian black shale in the Upper Yangtze region and its significance in oil and gas exploration
摘要
Abstract
The Lower Cambrian is one of the important exploration strata of marine shale gas reservoirs in the Upper Yangtze region,but its exploration is geologically impacted by multiple factors such as deep burial depth,fewer wells and unsatisfactory exploration results.In this paper,the mineral composition of the Lower Cambrian black shale in the Upper Yangtze region was investigated using the data of X-ray diffraction,rock thin section,scanning electron microscope (SEM) and argon ion polishing-electron microscope,and its significance in oil and gas exploration was also analyzed.The following findings were made.First,shale in this region is mainly composed of clay minerals and quartz,and secondarily of carbonate minerals and feldspar.The average content of quartz in shale is 44.6％,and two types of quartz are developed,i.e.terrigenous quartz and biogenic silica.The average content of clay minerals is 33.32％,with illite (Ⅰ)content being the highest,illite/smectite (I/S) layer content uneven,the mixed layer ratio lower,generally 5％,and chlorite (C) and kaolinite (K) locally distributed.Second,four types of clay mineral assemblages are identified,including I+I/S+C,transition from I+I/S+C to I+C,I+C,and I,indicating that diagenetic environments of shale are different in different areas.Third,the disordered arrangement of mineral grains is favorable for the survival of intergranular pores,indicating that in the diagenetic alteration process of feldspar into clay minerals,linear pores can be generated.It is concluded that the brittleness index of shale in this region is generally above 40％,indicating a good fragility.The fragility of shale in SE Guizhou is better than that in SW Sichuan Basin.关键词
上扬子地区/早寒武世/页岩/矿物组成/黏土矿物/组合类型/脆性指数/孔隙特征Key words
Upper Yangtze region/Early Cambrian/Shale/Mineral composition/Clay minerals/Assemblage type/Brittleness index/Pore characteristic引用本文复制引用
刘忠宝,高波,冯动军,崔学慧,杜伟,汪洋,李东晖..上扬子地区下寒武统黑色页岩矿物组成特征及其油气勘探意义[J].天然气工业,2017,37(4):21-26,6.基金项目
国家自然科学基金项目“高热演化条件下页岩气聚集机理和评价方法研究”(编号:41202103)、国家科技重大专项“彭水地区常压页岩气勘探开发示范工程”(编号:2016ZX05061)、中国石油化工股份有限公司科技开发部项目“中上扬子下寒武统页岩气甜点区研究”(编号:P15114). （编号:41202103）
