Coal Bed Methane

Coal Bed Natural Gas (CBNG), or Coal Bed Methane (CBM), wells produce gas from the coal seams which act as both the source and the reservoir. Natural gas can be sourced by thermogenic alterations of coal or by biogenic action of indigenous microbes on the coal. There are some horizontally drilled CBM wells and some that receive hydraulic fracturing treatments. However, wells frequently produce water as well as natural gas. Some CBM reservoirs are also underground sources of drinking water and, as such, there are restrictions on hydraulic fracturing. CBM reservoirs are mostly shallow as the coal matrix does not have the strength to maintain porosity under the pressure of significant overburden thickness. CBM plays also provide a very good means of CO2 sequestration because CO2 molecules displace CH4 methane molecules on the face of the coal, generating greater methane production while sequestering the CO2 in the coal bed.