ABSTRACT: This paper discusses how careful evaluation of the geomechanical properties of gob can be applied to gob degasification techniques in order to improve gas production and quality. It further describes the "best practices" for each method that may increase methane capture and purity. In both the commonly used methods, the cross-measure boreholes and vertical gob wells, the factors affecting gas purity and capture efficiency are geologic and reservoir conditions, appropriate borehole siting, orientation and spacing, and bore-hole integrity. The best practices for the techniques that might improve gas production and/or quality include appropriate siting of the boreholes to maintain integrity, proper borehole inclination, adequacy of well spacing, and targeting stress relief zones. An important implementation with significant potential improvement is continuous monitoring of the gas flow rates, quality and system pressure.

This content is only available via PDF.
You can access this article if you purchase or spend a download.