沉积与特提斯地质2024，Vol.44Issue(4)：796-808,13.DOI:10.19826/j.cnki.1009-3850.2024.07001
渝东北地区龙马溪组页岩孔隙结构特征及其主控因素
Pore structure characteristics and main controlling factors of the Longmaxi shales in northeastern Chongqing
摘要
Abstract
To investigate the pore characteristics and controlling factors of the Longmaxi shales in northeastern Chongqing,this study samples 12 shales from the Longmaxi Formation and utilizes physical experiments,including field emission scanning electron microscopy(FE-SEM),liquid nitrogen adsorption and carbon dioxide adsorption,to characterize the pore structures.The pore structure parameters are then compared with those of shales from different tectonic zones in the Sichuan Basin.The results indicate that the pores of shales in the Longmaxi Formation in northeastern Chongqing are predominantly comprised of organic matter pores,inorganic pores and micro-fractures.Compared to the marine shales with similar maturity in southern Sichuan,these samples exhibit relatively fewer and smaller organic matter pores but more developed inorganic pores and micro-fractures.Based on the pore-fracture characteristics,inorganic pores can be classified into three types:intergranular pores,interlayer pores in clay minerals,and intragranular pores.Micro-fractures are categorized as organic matter-related micro-fractures and inorganic mineral-related micro-fractures.The influence of TOC content on pore structure occurs in two stages:when TOC content is less than 5.93%,it exhibits a strong positive correlation with micropore volume and specific surface area;when TOC content is more than 5.93%,it shows a negative correlation with these factors,and no correlation with mesoporous parameters.In addition,there is no significant correlation between the inorganic mineral(clay and brittle mineral)content and pore parameters.The SEM images also show that the tectonic compression reduces pore volume and pore connectivity,leading to the conversion of free gas into adsorbed gas in shale reservoirs,thus improving the gas storage capacity of the shales.The research results provide a theoretical basis for shale gas exploration in complex structural areas.关键词
渝东北/龙马溪组/变形页岩/孔隙结构/主控因素Key words
northeastern Chongqing/Longmaxi Formation/deformed shale/pore structure/controlling factor分类
天文与地球科学引用本文复制引用
付文鼎,密文天,尚福华,麻书玮,朱悦雯,戴涛杰,朱炎铭,苗科,闫静,高海涛..渝东北地区龙马溪组页岩孔隙结构特征及其主控因素[J].沉积与特提斯地质,2024,44(4):796-808,13.基金项目
国家自然科学基金项目(42362022) （42362022）
内蒙古自然科学基金(2023QN04003,2024QN04003) （2023QN04003,2024QN04003）
内蒙古科技厅中央引导地方科技发展资金项目(2022ZY0083) （2022ZY0083）
内蒙古自治区高等学校碳达峰碳中和研究专项(STZX202212) （STZX202212）
中央引导地方科技发展资金(2022SZY0482) （2022SZY0482）
