Coalbed methane (CBM) has been the subject of renewed interest over the last few years as a new potential source of energy. Because of the structure of the natural fractures between coal seams in which the gas is found, well flows can be low. This means that considerable investment is often required to achieve reasonable gas flow rates.
The deliverability of wells is subject to significant variability both individually and overtime, which, when considering a large network, creates additional design uncertainty in defining an economic solution.
Uncertainty in individual well gas and water production rates production is a key challenge. A typical project can comprise hundreds of wells and dozens of individual well pads spaced over a large geographic area. Each of these pads will need connecting to the collection network. Thus for a typical development, several hundred wellhead gas/water separators and water disposal pumps will be required.
The most cost-effective development solution is likely to be one where standard building blocks (e.g. separators, pumps, low point drains, compressors) are readily available to be deployed at the optimum location.
In this report, the authors explain that when developing a CBM project, the challenge for designers often does not lie in the technical complexity of the processes and equipment, but in the scale of the development and the associated logistics.
Authors: Barrie Richmond, Paul Andrews, John Livermore and Paul Garlick
Read the article online at: https://www.worldcoal.com/cbm/04042014/getting_the_fundamentals_right_cbm006/