The objective is to avoid putting methane into the water line but allow it to flow up the backside of the well (casing) to the compressor station.
Tens of thousands of methane wells have been drilled, and extensive support facilities such as roads, pipelines, and compressors have been installed for CBM extraction in the Powder River Basin of northeast Wyoming and southeast Montana and now in India at West Bengal- Ranigunj, Panagarh, etc.
Environmentally acceptable disposal of brine is a major cost factor for economic methane production.
Gas content determination techniques generally fall into two categories: (1) direct methods which measure the volume of methane released from a coal sample sealed into a desorption canister and (2) indirect methods based on empirical correlations, or laboratory-derived sorption isotherm methane storage capacity data.
Laboratory sorption isotherms provide information about the storage capacity of a coal sample if these are measured under geological realistic pressure and temperature conditions.
Thus, the maximum gas content that can be expected for methane recovery can be assessed from such laboratory isotherm measurements.
Eddy and others constructed a series of curves estimating the maximum producible methane content of coal beds as a function of depth and rank.
A normal line is extended upward from the depth axis (feet) to intersect the specific coal rank curves.
Ash is an important indicator of clastic input, derived from marine or fluvial deposition of clay, silt, and sand during peat development.