天然气勘探与开发2023，Vol.46Issue(4)：133-147,15.DOI:10.12055/gaskk.issn.1673-3177.2023.04.014
川东北地区页岩气地质条件及其勘探潜力
Geological conditions and exploration potential of shale gas in northeastern Sichuan Basin:A case study of Upper Permian Wujiaping Formation in Well Fengtan 1
摘要
Abstract
The Upper Permian Wujiaping Formation in Sichuan Basin exhibits varying sedimentary facies laterally,and there develops a set of marine black shale in the northern Basin.Taking Well Fengtan 1 in northeastern Sichuan Basin as an example,the geological conditions for shale gas were studied by petrological,geochemical,scanning electron microscopy,low-temperature nitrogen adsorption and methane adsorp-tion methods.The results are as follows:(i)Two sets of black shale are developed in the Formation in the syudy area.One is in the second mem-ber of Wujiaping Formation(Wu 2 Member),consisting of grayish black to black clay shales of shore-side tidal flat facies,with low brittleness index and weak fracturability.The other is in the third member(Wu 3 Member),consisting of black siliceous and calcareous shales of deepwater shelf facies,with high brittleness index and strong fracturability.(ii)The Wu 2 Member shales have the average TOC of 1.41%,of which the black shale is relatively thin,with TOC>2%and Type III organic matters.The Wu 3 Member shales have the average TOC of 3.52%,of which the black shale is 26 m in thick,with TOC>2%and Type II1-II2 organic matters.Both sets are in the over-mature stage.(iii)The Wu 2 Member shales have the reservoir spaces mainly consisting of intergranular pores in clay minerals and microfractures,with relatively underdeveloped or-ganic pores.The reservoir pores are dominated by mesopores,followed by micropores,with a volume of 0.006 6 cm3/g and a gas content of 1.519 0 cm3/g.The Wu 3 Member shales have the reservoir spaces mainly consisting of organic pores,which are dominated by micropores,followed by mesopores,with an average volume of 0.014 1 cm3/g and an average gas content of 2.307 0 cm3/g.The pore structure and gas content are controlled significantly by the organic matter abundance,but not obviously by the mineral composition.(iv)The Wu 2 Member shales demon-strate relatively poor geological conditions and weak exploration potential.In contrast,the Wu 3 Member shales have favorable conditions and also good gas potential,with superior gas content and organic matter abundance to the Lower Silurian Longmaxi Formation.关键词
川东北地区/晚二叠世/黑色页岩/页岩气地质条件/勘探潜力Key words
Northeastern Sichuan Basin/Lower Permian/Black shale/Geological condition for shale gas/Exploration potential引用本文复制引用
明盈,孙豪飞,叶玥豪,王嘉先,宋金民,王宇峰,邱玉超,陈伟,戴鑫..川东北地区页岩气地质条件及其勘探潜力[J].天然气勘探与开发,2023,46(4):133-147,15.基金项目
国家自然科学基金重点项目"青藏高原东缘若尔盖古高原形成与破坏过程及其动力学机制"(编号:42230310) （编号:42230310）
国家自然科学基金面上项目"川西地区深层雷口坡组微生物岩及其储层形成机理研究"(编号:41872150). （编号:41872150）
