Abstract

Sorption or desorption time is a measure of diffusivity, defined as the length of time required for 63% of the gas to be desorbed from the coal sample. Varying sorption time will not affect the ultimate gas recovery but will shift the time for achieving peak gas production. Sorption time determined during the gas desorption studies of coal samples from core holes were used for modeling purpose in the present exercise. This can be indirectly calculated using cleat characteristics which can be obtained from Image log or field mapping.