Study On The Influence Of Extraneous Water On The Multicomponent Adsorption Characteristics Of Shale Gas

The Sichuan basin is the main area for shale gas exploration and development in China.Gas reservoirs have the characteristics of wide distribution thickness and high abundance of organic matter.Shale gas mainly exists in reservoirs in the adsorption state,and the ratio of water content to external water will affect the content of adsorbed gas.In this paper,Ps3,P2,P3 and P7 samples from Pengshui area were studied.The organic carbon content,maturity,main mineral composition and pore structure of the samples were determined.In addition,the adsorption gas volume of the four samples was tested under different water content and different proportion of external water.Finally,the experimental data are collated,analyzed,Langmuir model fitting and correction,L-F model fitting and correction,Toth model fitting and correction,D-A model fitting and correction.In addition,an adsorption model was established to consider the influence of distilled water and external water on shale isothermal adsorption.The main conclusions are as follows:(1)External water will reduce the pore volume of shale samples;(2)With the increase of water content,the adsorption gas amount of shale samples decreases;(3)As the proportion of external water increases,the isothermal adsorption gas amount of the shale sample decreases;(4)Compared with d-a model,the Langmuir model and L-F model are more suitable for fitting the adsorption gas capacity of shale samples with different proportions of distilled water and foreign water;(5)Establish the optimal D-A model considering the factors of the distill water and external water.