中南大学学报（自然科学版）2018，Vol.49Issue(6)：1447-1458,12.DOI:10.11817/j.issn.1672-7207.2018.06.018
湘西北牛蹄塘组页岩气储层岩矿特征及意义
Characteristics and significance of petrological-mineralogical of lower CambrianNiutitang formation shale gas reservoir in Northwest Hunan
摘要
Abstract
Considering that the analysis of mineral composition of shale is the basis of shale gas reservoir's evaluation as well as a key factor influencing accumulation of shale gas, Niutitang formation of lower Cambrian in Northwest Hunan was taken as the study object, mineral composition and its significance of Niutitang shale formation were systematically analyzed by section identification, XRD, field emission scanning electron microscopy(SEM) and low-temperature liquid nitrogen isothermal adsorption experiment. The results show that mineral components of Niutitang formation shale are diverse, which has a "two-low and one-high" characteristic (quartz content is high (mass fraction of 41.40%-60.81%) while clay minerals (mass fraction of 21.43%-26.40%) and carbonate minerals(mass fraction of 3.28%-16.10%) are low), in addition, these samples also generally contain calcite, plagioclase, dolomite, pyrite, potassium feldspar and other minerals. Compared with shale formations in different regions, Niutitang shale formation of lower Cambrian in Northwest Hunan has a property of diverse and abundant brittle minerals along with high brittleness index which is beneficial to reservoir fracturing. The combination of clay minerals reflects that Niutitang shale formation deposites in static water and hypoxia sedimentary environment under dry and cold climate condition, which is conducive to the enrichment and preservation of organic matter. The process of deposition and diagenetic burial goes through B-C substage of the late digenetic stage, water medium is basically alkaline which has high salinity of K+,Fe2+and Mg2+, and the organic matter is at high and over mature stages. Reservoir pores related to mineral composition are nano-clay minerals intergranular pores, pyrite intergranular pores and micron-level cracks. BJH total pore volume and BET specific surface area are normalized by total organic carbon, and the clay mineral content is positively correlated with the BET specific surface area, indicating that the clay mineral content has effect on adsorption properties of shale.关键词
页岩气/储层/岩矿组分/牛蹄塘组/下寒武统/湘西北Key words
shale gas/reservoir/components of rock and mineral/Niutitang formation/lower cambrian/northwest Hunan分类
天文与地球科学引用本文复制引用
焦鹏,郭建华,王玺凯,刘辰生,郭祥伟,黄俨然,刘博..湘西北牛蹄塘组页岩气储层岩矿特征及意义[J].中南大学学报（自然科学版）,2018,49(6):1447-1458,12.基金项目
国家自然科学基金资助项目(41603046) （41603046）
湖南省自然科学基金资助项目(2017JJ1034) （2017JJ1034）
中国地质调查局地质调查项目(DD20160183)(Project(41603046) supported by the National Natural Science Foundation of China （DD20160183）
Project(2017JJ1034) supported by the Natural Science Foundation of Hunan Province （2017JJ1034）
Project(DD20160183) supported by the China Geological Survey) （DD20160183）
