How is natural gas extracted from coal seams?
• CBM is attached or “adsorbed” to the coal itself, instead of being trapped in the pore space of the rock like most conventional natural gas. • Pressure from overlying rock and water within the natural fracture system of the coal seam keeps the methane gas bound to the coal. • CBM is produced by reducing the pressure in the coal seam, sometimes by pumping groundwater out, so the natural gas flows through fractures in the coal into the well bore. The natural gas would then flow up to the surface. • If few natural fractures exist, producers may use hydraulic fracturing to create channels in the coal. When the natural gas reaches the surface, it is compressed and transported through natural gas pipelines.
