Coalbed Methane Gas & Underground Coal Gas (Alternative Sustainable Energy Sources for The Future World)
Coalbed methane & Underground coal gas, briefly known as CBM & UCG respectively are the two newly invented methods in the field of applied mining technology to extract & produce gas from mined or non-mined coal seams. The extraction & production ways of these types of unconventional gas are differentiated from conventional gas production of two phase gas-oil reservoirs. Not only that but also the formation of unconventional gas is not similar to the conventional formation of gas associated with oil formation & gas cap. Here coalbed methane gas can be found from mined coal seams that don’t require any conversion process, where underground coal methane gas can be found from non-mined coal seams that must require additional conversion process. Approximately 5×1020 J energy is needed per year for consumption of about 700 million people all over the world. It is estimated that the energy distribution to the present world for domestic & industrial works is contributed by coal at 40.8%, natural gas at 21.6%, nuclear source at 10.6%, hydro at 16.4% & other sources including oil & water sources occupy the remaining portion. Since coal is the good source of heating energy & hence gas production is related with coal seam, then the significance of the CBM & UCG has been increased at a greater extent. These gases already have been able to attract the attentions of the coal bearing countries with their low detrimental effects & huge amount of availability. But there exists some essential challenging factors that should be faced before inaugurating CBM & UCG methods, such as greenhouse gas capture & sequestration process, dewatering process, subsidence pressure maintenance etc. If these challenges can be maintained & conducted scientifically so that any types of adverse effect can’t stand a barrier to these projects, then these methods will play a pioneering role in the field of sustainable energy sources in future. The intension of this report is to provide a overall theoretical review on these methods to all of you.
Keywords- Methane extraction, Coal gasification, Stimulation & completion methods, Coal deposits, GHG gas capture & sequestration, Gas content, Groundwater model design.