Abstract：CO₂adsorption capacity of shale in Longmaxi formation was characterized by CO₂isothermal adsorption experiment. The Langmuir volume ( VL) was calculated by Langmuir model. The pore types, topography characteristics, pore sizes distribution and specific surface area of the shale were described by using argon ion polishing scanning electron microscopy, high pressure mercury experiment, low temperature N2 adsorption experiment and low temperature CO₂adsorption experiment. Meanwhile, combined with organic carbon content ( TOC) and mineral composition, the influencing factors of shale adsorption and its impact mechanism were explored by using single factor analysis and multiple regression analysis. The results show that, there are four kinds of pores ( i. e. organic pore, clay mineral pore, intragranular pore and micro fissure pore) in micro-mesoporous scales of shale, of which organic pores are dominant and clay mineral pores are centralized developed in local. The affecting factors of shale adsorption capacity are pore structure parameters and basic reservoir parameters. For pore structure parameters, pore volume and specific surface area of microporous-mesoporous pores are the main controlling factors. For basic reservoir parameters, TOC is the dominant factor. Meanwhile, quartz and illite content have positive effects on the amount of adsorption. While, content of illite/smectite formation has negative effects on the adsorption. The results have theoretical values for CO₂geological sequestration and displacement of shale CH4.

Keyword：shale;reservoir;pore;CO2 adsorption characteristics;southeast Chongqing;Longmaxi formation;