ABSTRACT
Most geological strata have gases associated with them. CBM refers to the large density of gases (varying from 0.0003 to 18.66 m3/metric ton) stored in coal beds that have a multiporous structure. These gases are a mixture of methane (80%–99% of volume) and minor amounts of carbon dioxide, nitrogen, hydrogen sulfide, and sulfur dioxide. In the early nineteenth century, CBM was recognized as a major mine hazard because the presence of high-pressure gases in coal seams led to structural stress on mine beds and caused explosions and outbursts. To prevent this, these gases used to be drained or ventilated. However, the drainage of these gases into the atmosphere contributed to the greenhouse effect, since the global warming potential of methane is 25 times higher than that of CO2, measured over a 100-year period (IFP Energies Report 2008). In the late twentiethcentury, CBM began to be produced from conventionally drilled wells for use as a fuel, and soon it became recognized as an important unconventional source of natural gas (Flores 1998).
