Simulation of methane adsorption in diverse organic pores in shale reservoirs with multi-period geol

• 作 者: Shangbin Chen Chu Zhang Xueyuan Li Yingkun Zhang Xiaoqi Wang
• 机 构: Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process of the Ministry of Educa
• 出 处: 国际煤炭科学技术学报（英文版）
• 发表日期: 2021年5期
• 关键词: Adsorption mechanism Shale reservoir Diverse pores Multi-period geological evolu

In shale reservoirs,the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed methane.However,in the process of thermal evolution,the adsorption characteristics of methane in multi type and multi-scale organic matter pores have not been sufficiently studied.In this study,the molecular simulation method was used to study the adsorption characteristics of methane based on the geological conditions of Longmaxi Formation shale reservoir in Sichuan Basin,China.The results show that the characteristics of pore structure will affect the methane adsorption characteristics.The adsorption capacity of slit-pores for methane is much higher than that of cylindrical pores.The groove space inside the pore will change the density distribution of methane molecules in the pore,greatly improve the adsorption capacity of the pore,and increase the pressure sensitivity of the adsorption process.Although the variation of methane adsorption characteristics of different shapes is not consistent with pore size,all pores have the strongest methane adsorption capacity when the pore size is about 2 nm.In addition,the changes of temperature and pressure during the thermal evolution are also important factors to control the methane adsorption characteristics.The pore adsorption capacity first increases and then decreases with the increase of pressure,and increases with the increase of temperature.In the early stage of thermal evolution,pore adsorption capacity is strong and pressure sensitivity is weak;while in the late stage,it is on the contrary.