Abstract: The present invention is directed to a method of recovering energy from a subsurface petroleum formation by igniting the petroleum reservoir and burning as much petroleum as is possible thereby generating heat and recovering the heat so that it can be transformed into other forms of useful energy. The method also includes the steps of controlling the burning reservoir by injecting plugging agents into the more rapidly burning channels of the reservoir and by injecting oxidizing agents in spaced locations from the heat recovery location so that the burn pattern can be spread out over a selected area to maximize the recovery of energy from the selected area.

Abstract: This invention relates to the production of combustible gases from coal in situ, in which one or more passages are established between the surface of the ground and an underground coal deposit. The coal is set afire and the fire is sustained by injection of an oxidizer for a period of time. Oxidizer injection is terminated, followed by injection of steam for a period of time into the hot coal bed. Produced gases are captured at the surface. Products of combustion from the burn cycle are saved at the surface, reconstituted by the addition of oxygen, then reinjected for subsequent burn cycles until the sulfur dioxide content is sufficiently high to warrant recovery in surface facilities. Condensible gases are cooled in surface facilities with liquids captured apart from noncondensible gases.

Abstract: A method of extracting energy and chemical values from coal in situ including the steps of establishing passages among two or more coal seams underground and the surface of the ground wherein one coal seam is consumed by in situ combustion with the hot exit gases diverted through a second seam of coal enroute to the surface. The second seam of coal is dewatered, then subjected to pyrolysis, with enriched exit gases captured at the surface.

Abstract: The process of the invention includes the concept of igniting a coal formation in situ with hot granular material and subsequently allowing the material to flow into the burning coal formation to serve as a propping agent in the event of a cave-in. Gasifying agents are injected into the formation in an alternating pattern to alternately oxidize and reduce the coal environment to optimize the BTU content of the recovered gas. Further, a heat receptive liquid is circulated through the casing in the well connecting the coal formation to the surface to strip the sensible heat from the produced gases so that the heat can be used for useful purposes apart from the produced gas.

Abstract: A method of liquefying a coal formation in situ wherein the coal formation has been preheated as by a coal gasification project, includes the steps of establishing injection and removal passages connecting the coal formation to the surface, injecting water having a temperature below the formation temperature into the formation to gradually lower the temperature of the formation while forming synthesis gas, injecting a solvent material, having the capability of dissolving the coal, into the formation after it has been reduced to the desired temperature, injecting synthesis gas into the formation to hydrogenate the coal, allowing the formation to subside as the coal is dissolved therein so that more surface area of coal is exposed to the solvent, and removing the admixture of coal and solvent material from the formation as a synthetic crude oil.