Abstract: The method connecting wells by hydraulic-fracturing of a mineral bed, primarily for connection of wells in underground gasification of coal beds; using hydraulic-fracturing of a bed is effected intermediate a source-well into which a liquid is pumped under pressure and a well in the required direction; the head of the well with which connection is to be effected is sealed, whereas the heads of the wells, with which connection is undesirable, are opened; the liquid is pumped into the source-well under a pressure sufficient for initiating hydraulic-fracturing; the pressure in the well with which the source-well is to be connected is measured, and the moment the pressure in this well attains the hydraulic-fracturing value, the head thereof is immediately opened; upon the formation of a hydraulic fracturing fissure, the latter is flushed with the liquid; the method provides for building up a hydraulic-fracturing pressure in the well with which connection of the source-well is to be effected and thus controlling t

Abstract: Hydrocarbons are recovered from a subterranean hydrocarbon-bearing reservoir by in-situ combustion with minimum formation of water of combustion by fracturing the reservoir with a combustible fracturing mixture, burning the fracturing mixture, and thereafter injecting fluidized carbon in an inert gas carrier while at the same time injecting an oxygen-containing gas so that the fluidized carbon is burned in the fractures for thermal stimulation of production of hydrocarbons from the reservoir.

Abstract: Subterranean mineral deposits, such as oil shale or the like, are prepared for in-situ retorting by selectively mining out an area at the base of the deposit leaving an overlying deposit supported in a suitable manner such as by a plurality of pillars. The overlying deposit is expanded in any suitable manner into the underlying area in a fashion to create a predetermined distribution of permeability from an area of low permeability to an area of high permeability. An inlet is provided at the low permeability area and an outlet at the high permeability area. A suitable medium is introduced into the deposit at the low permeability end for extracting and forcing mineral values from the deposit toward the outlet end for recovery.

Abstract: A method for recovering low gravity viscous oils and bitumens from a subterranean formation by the simultaneous injection of an oxygen-containing gas and steam so as to control the combustion, followed by a conventional in-situ combustion, after which the formation may be scavenged by water injection.

Abstract: The rubble pile in an in situ reactor, which has a low length-to-diameter ratio and limited retorting gas inlets and outlets, has a radial bulk permeability distribution controlled to provide retort working gas flow paths from the inlets to the outlets with substantially even overall flow resistance. Channeling of retort gas along paths of low resistance is therefore avoided. An example of the controlled radial distribution of bulk permeability is a cylindrical, vertical in situ retort having a retort gas inlet and outlet on its longitudinal axis. The bulk permeability of the rubble pile progressively increases from the center to the wall of the reactor. The rubble pile is created by undercutting a carbonaceous deposit and expanding, as by explosives, the unexcavated deposit overlying the undercut.

Abstract: In producing shale oil by circulating hot fluid into and out of a rubble-containing cavern within a subterranean oil shale, plugging is avoided by permeating a portion of oil shale, consolidating a permeated portion, inflowing fluid outside the consolidated portion, and outflowing fluid from within the consolidated portion so the fluid is filtered through the consolidated portion.

Abstract: Method of and apparatus for extracting oil from oil shale. An excavating unit is driven by supplying steam to a plurality of steam engines mounted in an annulus between stationary outer and inner casings. A hollow center column and apertured screw vane are mounted for rotation in the inner casing and helical screw sections are provided outwardly of the inner casing at both ends of the apparatus for directing material to and from the inner casing. Steam is supplied to the unit for driving the center column and helical screws, with the steam supplied to the center column emanating through openings in the screw vane mounted in the inner casing for separating the oil from the oil shale by pyrolysis. The oil is withdrawn in the form of a vapor product by means of a vacuum applied to the inner casing for separation and condensation at the surface. Following excavation, the unit can be withdrawn to the surface under its own power.

Abstract: There is disclosed a method for the gasification of coal in situ which comprises drilling at least one well or borehole from the earth's surface so that the well or borehole enters the coalbed or seam horizontally and intersects the coalbed in a direction normal to its major natural fracture system, initiating burning of the coal with the introduction of a combustion-supporting gas such as air to convert the coal in situ to a heating gas of relatively high calorific value and recovering the gas. In a further embodiment the recovered gas may be used to drive one or more generators for the production of electricity.