Geochemical and gas bearing characteristics of the marine-continental transitional Longtan shales in southern Sichuan, China

• DOI: 10.3389/feart.2023.1202005
• Publication Date: 2023-07-07T12:38:55Z
• Authors: Yana Chen; Xiangyang Pei; Jizhen Zhang; Nan Wang; Denglin Han; Juan Wang; Xiao Xiao; Jianguo Wang
• Keywords: Longtan formation; reservoir; Science; Q; shale gas; Sichuan Basin; 01 natural sciences; geochemical characteristics; 0105 earth and related environmental sciences

Marine-continental transitional shale, as an important shale type, gains less attention than marine and continental which restricts the exploration development process of marine-continental gas. In this study, Upper Permian Longtan Formation in southern Sichuan Basin was taken research object, organic matter characteristics, hydrocarbon generation ability, mineral composition, physical properties, gas bearing characteristics were systematically analyzed. addition, effects abundance, maturity, components on adsorption capacity have been discussed detail. The results show that abundance varies greatly, with TOC value vast majority being greater 2.0%, carbon (TOC>12%) accounting for about 5%. main type is Type III, part II 2 . maturity stage high to over conducive dry There a good positive linear correlation between reflectance vitrinite ( R o ) maximum thermal decomposition peak temperature T max rock. higher matter, potential carbonaceous shows potential. rich clay minerals, highest content illite/smectite mixed layer. jointlypromote enrichment minerals beneficial adsorption, but poses challenge production fracturing.