Analysis Of Main Controlling Factors And Dynamics Simulation Of Shale Gas Adsorption

According to the difference of gas occurrence state,shale gas can be subdivided into three types: adsorbed gas,free gas and dissolved gas.Among them,adsorbed gas and free gas are the most important.However,compared with the free gas controlled by the gas state equation,the shale gas in the adsorption state has strong complexity in its occurrence characteristics and conversion mechanism,and its main control factors and adsorption mechanism are still not fully understood.Therefore,this paper takes Wufeng-Longmaxi Formation shale in Weiyuan,Changning and Jiaoshiba as research objects,and studies the main controlling factors and related mechanisms of the adsorption,through literature investigation,experimental analysis,molecular dynamics simulation and thermodynamic mechanism research,combined with geological conditions.And related mechanisms have been studied.Studies show that the main controlling factor of shale adsorption gas is organic matter,while organic matter includes organic matter content,pore structure,microscopic adsorption strength and adsorption site(reflected in the maturity of organic matter);in shale,compared with clay minerals,micropores developed by organic matter occupy most of the pores of the whole rock,thus controlling the specific surface area of the whole rock,and the organic matter has high microscopic adsorption strength and adsorption sites,and the specific surface area can adsorb more Shale gas,so organic matter mainly controls the adsorption of shale gas;for the study of temperature and pressure,although the temperature rise will inhibit the exothermic adsorption process,the shale gas adsorption is less sensitive to temperature in the temperature range of the study area,and because the formation pressure is much higher than the adsorption Langmuir pressure,therefore,within the pressure range of the formation,the influence of pressure on adsorption is very small,so the temperature and pressure is not the main factor controlling the adsorption of shale gas in the study area;because water and shale gas have a strong competitive adsorption relationship,the presence of water will significantly reduce the adsorption of shale gas,however,the water saturation of the study area does not change much(30%?40%),so the effect of water on the shale gas adsorption in the study area is not significant.