Abstract: Production of methane from an underground wet coal seam is initiated by drilling a well from the surface of the earth through the seam. Rather than pumping water to lower hydraulic head on the seam to permit desorption of methane within the coal, high pressure gas is injected into the seam to drive water away from the wellbore. Gas injection is terminated and the well is opened to flow. Initial gas production is return of injected gas, followed by a mixture of return injected gas and methane, followed by free methane from the fracture system of the coal, and then by methane desorbed from the coal. Upon return of displaced water to the wellbore, pumping operations remove water at rates that permit sustained production of desorbed methane.

Abstract: After a linkage channel is established through an underground coal seam connecting two vertical wells, a tubing bender/straightener is positioned in a first well aligned with the linkage channel. Oxidizer injection tubing is inserted from the wellhead into the tubing bender/straightener. The tubing is forced through the tubing bender/straightener and on into the linkage channel. The coal is ignited and the fire sustained by continuous injection of oxidizer through the tubing, creating a reaction zone separated from the first well with products of reaction recovered through the second well.

Abstract: Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.

Abstract: Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.

Abstract: Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.

Abstract: Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.

Abstract: The system of the invention comprises a two well system of gasifying coal in situ wherein the generated gas stream is directed to a gas separator, which, in turn separates hydrogen and carbon monoxide into separate streams. Hydrogen is directed to one type of fuel cell and carbon dioxide is directed to another with the resultant generation of electricity.The method of the invention comprises establishing two wells into an underground coal deposit with a reaction zone in fluid communication with the wells. Coal is gasified both in oxidizing and reducing environments, with the produced gas stream separated into its component parts. Combustible gases are directed to fuel cells with the resultant generation of electricity.

Abstract: In preparation for producing coal in situ two or more production wells are linked together through the coal seam by burned channels created by one or more blind hole burns.

Abstract: A water bearing underground coal seam is prepared for production by in situ techniques by drilling a series of wells into the seam. Paths of maximum permeability are determined by taking oriented cores in selected wells. The coal seam is partially dewatered by removing water from the seam in selected wells. Reaction zones are established in the coal, first along the paths of maximum permeability, then reaction zones are established substantially perpendicular to the original paths of maximum permeability.

Abstract: Coal gas is produced in situ using the techniques of gasification, liquefaction and pyrolysis. Normal effluents to the atmosphere are recycled in part to the underground reaction zone for conversion into commercial products. Contaminants to underground aquifers are captured and injected into the underground reaction zone for destruction and transformation into useful products.

Abstract: An underground carbonaceous deposit containing other mineral values is burned in situ. The underground hot zone is cooled down to temperature below the boiling point of a leaching solution. The leaching solution is percolated through the residial ash, with the pregnant solution recovered for separation of the mineral values in surface facilities.

Abstract: A previously mined underground coal deposit is sealed so that the underground void space can be pressurized for production by in situ techniques. Excavated communication passages are sealed by barricades which are further sealed by applying hydrostatic head pressure. Subsidence cracks are sealed by injection of mud slurry with additional sealing effected by maintaining hydrostatic head pressure with a column of the slurry. In situ production wells are drilled into the coal with hermetic seal accomplished in part by cementing a portion of the liner to the well bore and in part by the hydrostatic head pressure of a mud slurry positioned above the cement seal. Coal is ignited and burn patterns are established to cause reasonably uniform subsidence.

Abstract: Medium BTU gas is generated from coal in situ by establishing communication channels through the coal in part by projectiles and in part by burning. Oxygen is employed for reaction with the coal and reaction temperatures are controlled by injection of steam.

Abstract: A previously mined underground coal deposit is sealed so that the underground void space can be pressurized for production by in situ techniques. Excavated communication passages are sealed by barricades which are further sealed by applying hydrostatic head pressure. Subsidence cracks are sealed by injection of mud slurry with additional sealing effected by maintaining hydrostatic head pressure with a column of the slurry. In situ production wells are drilled into the coal with hermetic seal accomplished in part by cementing a portion of the liner to the well bore and in part by the hydrostatic head pressure of a mud slurry positioned above the cement seal. Coal is ignited and burn patterns are established to cause reasonably uniform subsidence.

Abstract: A method of producing combustible gases, synthetic crude oils, coal chemicals and heat from coal in situ utilizes the combined teachings of in situ gasification, liquefaction and pyrolysis.

Abstract: An underground coal fire is smothered by sealing the overburden for a minimum depth over the coal deposit. Wells are drilled into the fire area and the underground reaction zone is pressurized. Using various combinations of injecting oxidizers and reducing agents the coal deposit is produced in situ to yield a variety of useful products. Wells are cased without cement and with the hermetic seal attained by a column of slurry between the casing and well bore.

Abstract: A well is drilled from the surface of the earth into an underground coal formation. The coal seam is fractured by fluids injected under pressure. Methane entrained in the cracks and fissures is removed to surface facilities. Coal seam in the vicinity of well bore is partially dewatered. Diameter of well bore in the coal section is enlarged first by underreaming the hole, then by a vertical in situ burn to form a collection chimney. Methane desorbed from the coal is withdrawn to surface facilities.

Abstract: A method of producing combustible gases, synthetic crude oils, coal chemicals and heat from coal in situ utilizes the combined teachings of in situ gasification, liquefaction and pyrolysis.

Abstract: A method of producing combustible gases, synthetic crude oils, coal chemicals and heat from coal in situ utilizes the combined teachings of in situ gasification, liquefaction and pyrolysis in separated coal blocks.

Abstract: A method of producing combustible gases, synthetic crude oils, coal chemicals and heat from coal in situ utilizes the combined teachings of in situ gasification, liquefaction and pyrolysis in separated coal blocks.