Methane Adsorption\nand Desorption on Continental Shaly\nMatrix: Implications for Shale Gas Condensate Exploration and Production

Shale gas condensate is a burgeoning unconventional resource\nwith\nadsorbed methane (CH<sub>4</sub>) as its dominant component. Successful\nevaluation of marine shale gas gives limited insights into the evaluation\nof continental shale gas condensate due to their different occurrence\npatterns of organic matter and inorganic minerals and resultant contributions\nto pore development and CH<sub>4</sub> ad-/desorption capability.\nTo address this issue, we employed an advanced low-temperature oxygen\nplasma (LTOP) technology to extract organic matter from the continental\nshaly matrix. Results showed that the continental shaly matrix contains\nmore clay minerals and less quartz, and develops fewer pores and fractures\nthan typical marine shaly matrix. The organic matter-hosted pores\ninstead of inorganic mineral-hosted pores are more weighted to the\npore development in the continental shaly matrix. However, the inorganic\nminerals of the continental shaly matrix contribute more to CH<sub>4</sub> adsorption capability than the organic matter, which could\nbe attributed to the higher density of available adsorption sites\ntoward CH<sub>4</sub>. Besides, the CH<sub>4</sub> ad-/desorption\nhysteresis is more pronounced for the organic matter-free continental\nshaly matrix than the raw continental shaly matrix, which is attributed\nto the remarkable CH<sub>4</sub> adsorption-induced clay mineral swelling.\nOverall, the effects of inorganic minerals in CH<sub>4</sub> adsorption\nand desorption, particularly clay minerals, are crucial for continental\nshale gas condensate exploration and production.