Repeat: The three main unconventional gas techniques are shale gas, coal bed methane (CBM/CSG) and underground coal gasification (UCG), which literally involved setting fire to coal seams underground to exploit the energy released.
The three main unconventional gas techniques are shale gas, coal bed methane (CBM/CSG) and underground coal gasification (UCG), which literally involved setting fire to coal seams underground to exploit the energy released.