Effects Of Pore Structure And Wettability On Adsorption Capacity Of Highly Evolved Marine Shale

The gas bearing capacity of shale reservoir is closely related to shale adsorption capacity,which is controlled by many factors such as pore structure characteristics and wettability of the reservoir,and finally affects the degree of shale gas enrichment.Taking the shale of Wufeng Longmaxi formation in South Sichuan as an example,this paper studies the factors influencing the adsorption capacity of shale reservoir.Through XRD,rock pyrolysis,nitrogen adsorption,scanning electron microscope,high-pressure mercury injection,contact angle test,methane isotherm adsorption and other experiments,comprehensively analysis the control effect of shale adsorption capacity and have obtained the following points:(1)TOC content of shale reservoir is high,organic matter is high The more developed the pores,the stronger the lipophilic property and the better the connectivity of the lipophilic pores are,the better the adsorption and preservation of shale gas is;(2)The influence of clay mineral content on the adsorption of shale gas is complex,the presence of clay minerals is conducive to the development of micropores in the reservoir,and the increase of the lipophilic wettability after the reservoir contacts with shale gas is conducive to the adsorption and preservation of shale gas,but because of the instability of clay minerals;(3)The higher the water saturation of shale,the more adsorption sites occupied by water molecules,and the easier to agglomerate and block pores,which is not conducive to shale gas adsorption.It is of great theoretical significance and practical value to study the influencing factors of shale adsorption capacity,to reveal the adsorption mechanism of shale and marine shale in South Sichuan,to find out the adsorption capacity of shale under different geological conditions and to effectively evaluate the enrichment degree of shale gas.The analysis of shale adsorption capacity and its control in the study area can provide support for shale gas resource evaluation and subsequent exploration and development in southern Sichuan and marine shale gas.