So called unconventional gas is just plain old methane – CH4. It is unconventional in the way that it is extracted and where from, rather than what it actually is. Gas extracted is not pure methane and will contain some other gases. The main types of unconventional gas extraction are:
- Coalbed Methane (CBM)
- Shale Gas
- Coal Gasification
- Gas recovery from active or abandoned coal mines.
Coal gasification is not an issue in the Chew Valley, but CBM and Shale Gas are. Hydraulic fracturing, also know as fracking, is a technique used to liberate the gas from either coal seams or from shale rocks deep beneith the surface. The licence holders in this area ( UK Methane and Eden Energy ) are interested initially in CBM and potentially in shale gas in the future. They are currently seeking locations to conduct stratigraphic tests.