Mining Publication: Degasification of the Mary Lee Coalbed Near Oak Grove, Jefferson County, Alabama, by Vertical Borehole in Advance of Mining
A 5-hole pattern was drilled from the surface at a site near Oak Grove, Jefferson County, Alabama, to degasify the gassy Mary Lee coalbed in advance of mining. Gas and water production was monitored for 1 year, 4 months to allow gas flow to stabilize fully. A thickened water stimulation treatment was designed and applied in one hole of the pattern to evaluate this degasification technique for the Mary Lee coalbed. A gas production rate of 70,000 ft3/day after stimulation treatment indicates that the use of vertical boreholes coupled with hydraulic fracturing in advance of mining the Mary Lee coalbed would provide for more rapid degasification and could provide a possible source of natural gas.