Coal-seam methane drainage by hydraulic fracturing providing the methane for energy while enhancing mining safety and efficiency
Coal seams in the United States contain vast quantities of methane gas. Gas contained in the coal seams currently being mined diffuses into the mine and has to be removed by ventilation air and is lost as an energy resource. Because of the quantities of this gas in certain areas (350 to 400 cu ft/ton of coal mined) the ventilation costs can run as high as $3.50 per ton of coal mined. This gas also constitutes a safety hazard and reduces the efficiency of mining. Methane explosions take lives of several miners every year. The government, through the Department of Energy and the US Bureau of Mines, has been conducting research projects to develop ways of removing the gas ahead of mining. The aim of this research is not only to improve the safety and reduce the mining costs, but to gather the gas and provide it as an energy resource to a pipeline or for local use. The energy contained in the coal seam gas is estimated to be up to 2% of that available from the coal. Two techniques have emerged as the primary candidate for draining the entrapped methane ahead of mining. These are horizontal drilling into the coal face and hydraulic fracturing, a method used to enhance production of oil and gas reservoirs. The latter is the principal focus of the paper. Mine operators have shown resistance to the application of both techniques. In the case of horizontal drilling, the resistance is seen because of the extra activity and equipment requirements to drill the hole and to manifold the gas back through the mine to the surface. With hydraulic fracturing, the miners have been concerned because, in some cases, the hydraulic fractures have propagated into the roof and floor rock, possibly compromising the structural integrity of the mine near the fractures.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA); Bureau of Mines, Pittsburgh, PA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7023077
- Report Number(s):
- UCRL-87635; CONF-820814-37; ON: DE83000749
- Resource Relation:
- Conference: 17. Intersociety Energy Conversion Engineering conference, Los Angeles, CA, USA, 8 Aug 1982; Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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03 NATURAL GAS
COAL SEAMS
DEGASSING
HYDRAULIC FRACTURING
METHANE
RECOVERY
UNDERGROUND MINING
EFFICIENCY
SAFETY
VENTILATION
COAL MINING
ALKANES
COAL DEPOSITS
COMMINUTION
FRACTURING
GEOLOGIC DEPOSITS
HYDROCARBONS
MINERAL RESOURCES
MINING
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012000* - Coal
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