The hydrocarbons which are found in the nature and their percentage of underground are shown in Figure1. It contains many kind of hydrocarbons and the others that aren’t hydrocarbon, hydrocarbon compounds are methane 65%, ethane 7%, propane 4%, butanes 2%, pentanes 1%, carbon dioxide 20%, nitrogen 2% and others (As shown in Figure 1). The others contaminated which found in natural gas are hydrogen sulfide, helium, and steam. These vapors are adsorbed in coal located underground with the main composition of methane and carbon dioxide. This system is well known as coal seam gas system.