Large quantities of methane gas which now are vented from mines could be produced from coal-gas wells. Eight of these coal-gas wells have been completed in the Pittsburgh coal bed at the Emerald Mine near Waynesburg, Pennsylvania. The Bureau of Mines has provided foam stimulation for five of these wells. The foam treatments used an average of 8,200 gal of water, 40 gal of foaming agent, 10,900 lb of 10/20- or 20/40-mesh proppant sand, and 300,000 cu ft of nitrogen. These treatments had an average injection pressure of 1,376 psig, at an average rate of 12 bbl of foam per minute, and 1/4 to 1 lb of sand per gal of foam. Production from two of the wells, which are dewatered, has averaged over 100,000 cu ft/day for several months. Additional wells were completed in the Mary Lee coal bed and show even more promising results. These projects should show that degasification in advance of mining is feasible and economical.
Proc. Aapg-sepm Ann. Conv., Oklahoma City, Oklahoma, April 9-12, 1978, PP. 115