Shale Gas and Coal-bed Methane Fossil fuels (such as gas, oil and coal), are produced by the slow decomposition of organic matter buried underground as a result of increased temperature and pressure. Shale gas and CBM differ from conventional gas reservoirs as the gas is directly extracted from the rock that was the source of the gas (shale and coal respectively). Shale Gas: Shale gas refers to natural gas that is trapped within fractures and pore spaces within fine-grained sedimentary shale rocks. The Tyndall Centre (2011) identified two major drilling techniques that are used in combination with one another to extract shale gas – horizontal drilling and hydraulic fracturing : ▼Horizontal drilling is used to provide greater access to the gas trapped deep in the producing formation. At the desired depth, the drill bit is turned to bore a well that stretches through the reservoir horizontally, exposing the well to more of the producing shale; ▼Hydraulic fracturing is where fluid