ABSTRACT
Coal acts as both source rock and reservoir rock for methane. This methane extracted from coal seams is known as coal seam gas. Methane is a common source of energy used in modern society and at the same time it is an environmental hazard, as a combustible gas in underground coal mines and as a greenhouse gas in the atmosphere. Hence, its evaluation, extraction, and related environmental issues are important. Methane remains mostly as adsorbed molecules on micropores in coal. “Direct method” using a desorption canister is used for determining the gas content of coal and its storage capacity is determined through adsorption isotherm construction. Coal seam gas extraction involves drilling, well completion, and well stimulation. Main environmental concern is the disposal of the co-produced water which has high soda content. The chapter provides a synoptic view on various evaluation and extraction techniques of coal seam gas with a brief on clean coal technologies which addresses the associated environmental concerns of coal usage.
