Abstract: An in-situ thermal desorption system and process is utilized for mobilization and removal of nonvolatile and semi-volatile hydrocarbons from contaminated soil in the vadose zone. Persistent hydrocarbons are thermally desorbed by direct heating of the contaminated zone through combustion of fuel and air in a burner underneath the contaminated soil zone. The generated soil vapors are collected and treated by soil vapor extraction techniques.

Abstract: A downhole burner that economically generates hot inert gas and injects this gas into a subterranean formation. The burner has a nipple attached to a first tubing string that carries an oxidizer to the burner. The first tubing string also contains a coil tubing string that carries fuel to a movable nozzle inside the nipple. A small orifice in the nozzle increases the velocity of the fuel, and the nozzle extends out through a small orifice in a burner shroud that increases the velocity of the oxidizer flowing around the nozzle. The high velocity of the fuel and oxidizer keeps the flame front below the shroud and nozzle. A second tubing string supplies coolant gas around the burner shroud. Injection of an oxygen containing coolant gas provides a method for enhancing in situ combustion reactions through superheating the oxygen containing mix of coolant and exhaust gas.

Abstract: A method for heat injection into a subterranean diatomite formation is provided. The method utilizes a heater that is placed directly in the diatomite formation without cement around the heater. Diatomite is very soft, and will quickly fill in around the heater, operation of the heater will sinter the diatomite and significantly increase the original thermal conductivity and strength of the diatomite.

Abstract: A method for heat injection into a subterranean formation is provided. The method utilizes flameless combustion and a gas fired heater having an electrical heated surface for ignition of the gas. The absence of a flame eliminates the flame as a radiant heat source and results in a more even temperature distribution throughout the length of the burner. Flameless combustion is accomplished by preheating the fuel and the combustion air to a temperature above the autoignition temperature of the mixture. Preheating hydrocarbon fuel requires the inclusion of a carbon formation suppressant such as carbon dioxide or steam to prevent carbon formation.

Abstract: A process to recover oil is provided wherein an oil containing subterranean formation is heated by conductive heat transfer. The high temperature levels of this process result in high recoveries of initial oil in place, and recovery of the oil within a short time period. This process is particularly applicable to diatomite formations that have low permeabilities.

Abstract: A process to recover oil is provided wherein an oil containing subterranean formation is heated by conductive heat transfer from heat injectors operating at temperatures above 900.degree. C. The high temperature levels of this process result in high recoveries of initial oil in place, and recovery of the oil within a short time period. This process is particularly applicable to diatomite formations that have low permeabilities.

Abstract: A method for heat injection into a subterranean formation is provided. The method utilizes flameless combustion. The absence of a flame eliminates the flame as a radiant heat source and results in a more even temperature distribution throughout the length of the burner. Flameless combustion is accomplished by preheating the fuel and the combustion air to a temperature above the autoignition temperature of the mixture. Preheating hydrocarbon fuel requires the inclusion of a carbon formation suppressant such as carbon dioxide or steam to prevent carbon formation.

Abstract: A downhole gas generator can be ignited downhole by an ignitor mixture combining with an oxidant. The ignitor mixture is provided by an ignitor subsystem. In one embodiment, the ignitor subsystem bubbles gaseous fuel through a chamber of liquid pyrophoric. The chamber is heated, wherein the fuel obtains a vapor content of the pyrophoric, forming a gaseous ignitor mixture. In another embodiment, gaseous fuel is turbulently injected into a chamber. Liquid pyrophoric enters the chamber through an orifice. The fuel passes through a nozzle wherein its pressure is reduced. This pressure drop is imposed on the pyrophoric, wherein the pyrophoric is drawn into the chamber. The fuel mixes with and atomizes the pyrophoric to form an ignitor mixture.

Abstract: A separate heat source, such an a skin effect heater, is added to a subterranean heat exchanger and oxygen combustion device for upgrading viscous crude oil feeds. An insulated wire is integrated with combustion oxygen supply piping to form the skin effect heater operating in conjunction with the heat exchanger. The separately controlled heater output allows a reduction of the heat from the combustion device reduced quantities of combustion products. The improvement down-sizes or eliminates excess combustion product removal facilitates and also preheats the oxygen supply. The skin-effect heater and heat exchanger combination adds heat gradually and increases feed residence time at the desired upgrading temperature and pressure conditions. Alternative embodiments can be used to treat heavy crudes within a producing well.

Abstract: An in situ thermal system is disclosed for enhanced oil recovery and the like from a subterranean formation. The system pressurizes the formation with water whereupon the entire formation is heated to relatively high temperatures in the absence of gas formation to significantly decrease the viscosity of substantially all the crude in the formation and permit recovery thereof. A down hole, fuel fired radiant tube burner of long length is provided to achieve the desired heat patterns within the formation. The burner includes three concentric, closed end tubes with the innermost tube containing a burner and spaced closely adjacent the intermediate tube. A hole pattern in the innermost and intermediate tube establishes a laminar flow of the burner's products of combustion therebetween which modifies the radiation heat flux pattern so that uniform heat is emitted from the outermost tube along its length.

Abstract: A method and apparatus for recovering hydrocarbons in a which a first toroidal vortex of fuel and a combustion supporting gas is created with its center adjacent the axis of an elongated combustor; a second toroidal vortex of combustion supporting gas is generated between the first toroidal vortex; the fuel is burned in the presence of the combustion supporting gas to produce a fuel gas at the downstream end of the combustor; water is introduced into the flue gas adjacent the downstream end of the combustion to produce a mixture of flue gas and water; a major portion of the water is vaporized in a vaporizor to produce a mixture of flue gas and steam; and the mixture of flue gas and steam is injected into a hydrocarbon bearing formation.

Abstract: An apparatus is disclosed for improving the transportability of a hydrocarbon stream by reducing its viscosity. The apparatus comprises a reactor vessel useful for providing an incremental amount of heat to a hydrocarbon stream by the introduction of an oxidizing agent into the core portion of the stream. The reactor comprises an influent conduit and an effluent conduit in heat exchange relation with each other, at least one oxidant injection nozzle located in either or both the influent and/or effluent conduits, a conduit to transport oxidant to the nozzles and a valve in the oxidant conduit to control oxidant flow to the nozzles. The reactor can also contain temperature monitors in the influent and/or effluent conduits and an oxidant flow controller device responsive to output from the temperature monitors and adapted to adjust oxidant flow to maintain temperatures in the reactor reaction zone within a preselected range.

Abstract: Disclosed is a catalytic combustor and systems for the boilerless stoichiometric production of a working fluid such as steam from a fuel-mixture comprised of a carbonaceous fuel and a diluent such as water mixed in a thermally self-extinguishing mass ratio. Production of the steam is by a controlled substantially stoichiometric process utilizing a combustor to provide steam over a wide range of heat release rates, temperatures and pressures for steam flooding an oil bearing formation. Even though formation characteristics change during a steam flooding operation, output steam of the combustor may be kept at a constant heat release rate by dividing the total amount of water passing through combustor between a first portion which is included in the fuel-mixture and a second portion which is injected into the heated products of combustion.

Abstract: A method and apparatus for recovering hydrocarbons in which a first torroidal vortex of fuel and a combustion supporting gas is created with its center adjacent the axis of an elongated combustor; a second torroidal vortex of combustion supporting gas is generated between the first torroidal vortex; the fuel is burned in the presence of the combustion supporting gas to produce a flue gas at the downstream end of the combustor; water is introduced into the flue gas adjacent the downstream end of the combustor to produce a mixture of flue gas and water; a major portion of the water is vaporized in a vaporizor to produce a mixture of flue gas and steam; and the mixture of flue gas and steam is injected into a hydrocarbon bearing formation.

Abstract: A method and apparatus for stimulating a subsurface, oil-bearing reservoir, in which a fuel is burned in the presence of a combustion-supporting gas to produce an essentially uncontaminated flue gas at a pressure significantly above the reservoir pressure, water is intimately mixed with the flue gas, the water is vaporized to produce a mixture of flue gas and steam and the operating parameters of the water vaporization and, particularly, the fuel combustion are controlled by passing the mixture of flue gas and steam through an iris-type shutter having a variable diameter opening and varying the diameter of the variable diameter opening.

Abstract: A downhole steam-generating system in which fuel and compressed air from an air compressor unit 20 are fed to a steam generator 22. Steam and/or combustion products are fed to the turbine 24 from the steam generator 22 and the turbine 24 is used to mechanically drive the air compressor unit 20. After leaving the turbine 24, the turbine output may be scrubbed and the combustion products may be either passed down the borehole with the steam or may be discharged into the atmosphere.

Abstract: A method for starting up the production of hydrocarbonaceous fluid from a wellbore which has been shut-in for a time such that the ratio of water to hydrocarbon present in the hydrocarbonaceous fluid in the wellbore is sufficiently high as to make it uneconomic to produce hydrocarbonaceous fluid from said wellbore, the improvement comprising heating the reservoir around said wellbore and the hydrocarbonaceous fluid contained therein suficiently to cause the said hydrocarbonaceous fluid to be substantially less viscous and to cause at least some thermal expansion of said hydrocarbonaceous fluid whereby the water to hydrocarbon ratio is decreased to a value at which hydrocarbonaceous fluid can be economically produced from said wellbore and thereafter starting up production of hydrocarbonaceous fluid from said wellbore.

Abstract: A steam generator having substantial thermal capacity for producing high quality steam used primarily for downhole steam generation in tertiary oil recovery. Incorporated in the generator is a novel high pressure, high heat release combustor, utilizing high pressure gaseous fuel and compressed gas oxidizer such as air, wherein thermal and mechanical stresses on the combustor structure are controlled. A method for controlling combustion induced mechanical stresses on the combustor through fluid injection is also disclosed. Disclosed designs provide substantially increased combustor life in "Downhole" Steam Generation service. The burner employs an ignition technique utilizing gaseous injection of a pyrophoric compound such as triethylborane (TEB).

Abstract: A method for the recovery of mineral resources, such as metallic minerals, petroleum, etc., from solid materials, such as subsurface earth formations, including; partially burning a hydrogen-containing fuel in the presence of an oxidizing agent under conditions to produce partial oxidation products, such as alcohols, hydrogen peroxide, aldehydes, ketones, etc., terminating the burning to prevent decomposition of the partial oxidation products and contacting the solid materials with the partial oxidation products and contacting the solid materials with the partial oxidation products and an alkaline or acidic material.

Abstract: Viscous oil is recovered from a subterranean, viscous oil-containing formation by a steam flooding technique wherein steam is generated in a downhole steam generator located in an injection well by spontaneous combustion of a pressurized mixture of a water-soluble fuel such as sugars and alcohols dissolved in water or a stable hydrocarbon fuel-in-water emulsion containing an anti clay-swelling agent and substantially pure oxygen. The generated mixture of steam and combustion gases pass through the formation, displacing oil and reducing the oil's viscosity and the mobilized oil is produced from the formation via a spaced-apart production well. Suitable anti clay-swelling agents include metal halide salts and diammonium phosphate.

Abstract: A steam generator for producing steam in a confined space such that it can be positioned in a borehole for use in secondary and tertiary recovery of hydrocarbons. Fuel is injected axially into a combustion chamber having a reduced orifice in the bottom thereof and oxygen is introduced tangentially from a plurality of ports in the top of the combustion chamber to create a stable vortex flame. A portion of the walls of the combustion chamber are formed from a porous, sintered stainless steel cylinder through which water is pumped to cool the walls of the chamber and to form steam. The combustion products are mixed with a water mist in a steam generating section to form steam.

Abstract: The combustor comprises a single sheet of metal coated with catalyst and wound into a spiral. There is a single spiral passage leading into the core of the spiral. The fuel-air mixture burns on the catalyzed surface of the spiral, and heat is transferred through the metal wall of the spiral to the incoming fuel-air mixture. The incoming fuel-air mixture is preheated to a temperature sufficient to start the catalytic combustion. The fuel content in the mixture can be below the flammability limit. The combustor is compact so that it can be used as a catalytic air preheater in a downhole steam generator.

Abstract: In accordance with the present invention, microorganisms are controlled in a body of fluid, particularly an aqueous fluid containing such microorganisms, by burning a hydrogen-containing fuel in the presence of an oxidizing agent under conditions sufficient to produce partial oxidation products, containing significant amounts of at least one compound capable of controlling microorganisms, such as hydrogen peroxide and aldehydes controlling the burning step to prevent significant decomposition of the thus produced partial oxidation products and the formation of products of complete combustion therefrom by controlling the burning step by selecting at least one of the type of hydrogen-containing fuel, the fuel/oxidizing agent equivalence ratio, the temperature, the pressure and the residence time, preferrably the residence time by introducing a quench medium, particularly water, into the partial oxidation products, to produce an effluent containing said partial oxidation products containing including at least on

Abstract: Viscous oil is recovered from a subterranean, viscous oil-containing formation by a steam flooding technique wherein steam is generated in a downhole steam generator located in an injection well by spontaneous combustion of a pressurized mixture of a water-soluble fuel such as sugars and alcohols dissolved in water or a stable hydrocarbon fuel-in-water emulsion containing an anti clay-swelling agent and substantially pure oxygen. The generated mixture of steam and combustion gases pass through the formation, displacing oil and reducing the oil's viscosity and the mobilized oil is produced from the formation via a spaced-apart production well. Suitable anti clay-swelling agents include metal halide salts and diammonium phosphate.

Abstract: A pumping system (10) is disclosed for pumping a fluid (14) from within a borehole (12) to the surface. A combustion engine (18) is employed to drive a pump comprising a pump barrel (28) and an auger pump shaft (32). The pumped fluid is carried from the borehole in a fluid return tubing string (42) having a standing valve (44) therein to prevent backflow into the borehole. A fuel-air mixture is provided to the combustion engine (18) through a fuel-air tubing string (22). A byproduct of the combustion of the fuel-air mixture is heat. The combusted mixture is exhausted from the combustion engine (18) through an engine exhaust tubing string (60). The engine exhaust tubing string includes a heating coil portion (64) forming a heat exchanger to transfer heat from the combusted fuel-air mixture to the fluid (14) adjacent the inlet of the pump to reduce the viscosity of the fluid to enhance the efficiency of the pumping system.

Abstract: A silane propane burner for an underground coal gasification process which is used to ignite the coal and to controllably retract the injection point by cutting the injection pipe. A narrow tube with a burner tip is positioned in the injection pipe through which an oxidant (oxygen or air) is flowed. A charge of silane followed by a supply of fuel, such as propane, is flowed through the tube. The silane spontaneously ignites on contact with oxygen and burns the propane fuel.

Abstract: The present invention provides an indirect downhole steam generator system comprising a downhole combustor, a well casing which provides a flue for the exhaust gases of the downhole combustor, and one or more aerosol nozzles situated within the exhaust flue of the well casing for injecting an aerosol limestone dust into the exhaust gases of the combustor as the exhaust gases travel up the flue.

Abstract: Viscous oil is recovered from a subterranean, viscous oil-containing formation by a steam flooding technique wherein steam is generated in a downhole steam generator located in an injection well by spontaneous combustion of a pressurized mixture of a water-soluble fuel such as sugars and alcohols dissolved in water or a stable hydrocarbon fuel-in-water emulsion and substantially pure oxygen. The generated mixture of steam and combustion gases pass through the formation, displacing oil and reducing the oil's viscosity and the mobilized oil is produced from the formation via a spaced-apart production well.

Abstract: The present invention relates to a process for increasing the yield of hydrocarbons from an underground hydrocarbon-bearing formation penetrated by a borehole and wherein a gas generator is located in the borehole at or above the level of the formation. The gas generator includes a housing forming a chamber and having an upper inlet end for receiving fuel, a catalyst assembly in an upper region of the chamber, a gas-generating reaction chamber below the catalyst assembly, this reaction chamber having a separate chemical reactant inlet and a restricted lower outlet for the passage of hot gaseous reaction products.

Abstract: A steam generator including a combustion chamber having fuel and air inlets at the upstream end and a water inlet at the downstream end to inject water into the flue gas, a vaporizer in communication with the downstream end of the combustor and a pressure control to vary the size of the discharge opening of the vaporizer and thus control the pressure within the combustor and vaporizer, including; a slideably movable plug attached to and operable by a fluid operated piston.

Abstract: A method for initiating an in-situ combustion process for the recovery of oil from a subterranean, viscous oil-containing formation wherein a combustible gas such as natural gas or methane and a mixture of oxygen and carbon dioxide containing 55 to 80 volume percent carbon dioxide is injected into a downhole burner in the injection well and ignited to produce combustion gases containing heat energy that pass into the formation. After the area of the formation surrounding the injection well reaches a temperature within the range of 500.degree. to 800.degree. F., injection of the combustible gas is terminated and injection of the mixture of oxygen and carbon dioxide is continued to initiate in-situ combustion in the formation. Thereafter, essentially pure oxygen is injected into the formation to support in-situ combustion in the formation for the recovery of oil therefrom.

Abstract: A pressure regulating and relief valve assembly, such as an assembly positionable in a lower portion of a well casing. The valve assembly has a main relief valve assembly or back pressure regulator that is designed to open when the steam pressure exceeds a first predetermined value. A secondary relief valve assembly is provided to vent excess pressure to a space exterior of the valve assembly when the pressure exceeds a second predetermined value, the second value being higher than the first value. The valve assembly is positionable within a well casing at the bottom of a bore hole between a steam generator and a probe utilizing the steam generator. When the assembly is so positioned, excess pressure is vented to a space between the valve assembly and the inner surface of the encompassing well casing.

Abstract: Viscous oil is recovered from a subterranean, viscous oil-containing formation by a steam flooding technique wherein steam is generated in a downhole steam generator located in an injection well by spontaneous combustion of a pressurized mixture of a water-soluble fuel such as sugars and alcohols dissolved in water and substantially pure oxygen. The generated mixture of steam and combustion gases pass through the formation, displacing oil and reducing the oil's viscosity and the mobilized oil is produced from the formation via a spaced-apart production well.

Abstract: The present invention provides a steam generator which comprises rocket-type multielement injector head and a small diameter, highly elongated, cylindrical combustion chamber whose walls are formed from a plurality of longitudinally adjoined water tubes. The multielement injector head injects an array of associating streams of fuel and oxidizer into the combustion chamber under sufficient pressure to maintain a combustion pressure in the range of 25-150 psia whereupon the narrowness of the combustion chamber serves to constrict the resultant combustion gases to thereby promote radiant and convective heat transfer from the flame of combustion through the walls of the combustion chamber into the water passing through the water tubes. By such arrangement the production of nitrogen oxides in the combustion chamber is avoided.

Abstract: Disclosed is a method and apparatus for generating high pressure steam within a well bore. The steam vapor generator is constructed for receiving and mixing high pressure water, fuel and oxidant in a down-hole configuration. High pressure water is received within a heat exchanger constructed around a combustion chamber in an annular sleeve configuration and heated through a thermal wall region forming a lower portion thereof. The combustion chamber utilizes the heat energy of radiation to heat the water flowing in the annular sleeve to the point of steam. The heat exchanger further includes a series of open ended flow tubes which triplicate the length of the flow path of the water prior to egressing from the sleeve. A collection chamber is provided beneath the combustion chamber in communication with the heat exchanger for the mixing of the high pressure vapor and the exhaust thereof into the adjacent well formation.

Abstract: A burner system particularly useful for downhole deployment includes a tubular combustion chamber unit housed within a tubular coolant jacket assembly. The combustion chamber unit includes a monolithic tube of refractory material whose inner surface defines the combustion zone. A metal reinforcing sleeve surrounds and extends the length of the refractory tube.

Abstract: Thermal treatment apparatus for downhole deployment comprising a combustion stage with an elongated hot wall combustion zone for the substantially complete combustion of the fuel-air mixture and an ignition zone immediately upstream from the combustion zone in which a mixture of atomized liquid fuel and air at or below stoichiometric ratio is ignited; together with a water injection stage immediately downstream from the combustion zone through which essentially partuculate free high temperature combustion products flow from the combustion zone and into which water is sprayed. The resulting mixture of steam and combustion products is injected into an oil formation for enhancing the speed and effectiveness of reservoir response due to physical, chemical, and/or thermal stimulation interactions.

Abstract: A method comprises (1) piping of exhaust steam flow from a down hole steam generator positioned at the top of a petroliferous reservoir down to the bottom of the reservoir, and (2) reversing the direction of hot exhaust steam flow to saturate the complete petroliferous reservoir wall surface with the steam of uniform quality, the steam having uniformity of distribution of both liquid and vaporous phases for improved enhanced oil recovery. A new steam generator is also disclosed.

Abstract: Tubing which contains crude oil being moved to the surface is surrounded by concentric sections of pipe at various depths along portions of the tubing. Said concentric sections of pipe contain a porous media incorporating an oxidizing catalyst in the annulus between said pipe and the tubing. A fuel and oxygen containing gas is passed down the tubing/casing annulus and passes through the catalyst bed causing the fuel to burn. The exhaust gas may be passed to the surface or it may enter the crude containing tubing to assist in gas lifting the crude to the surface. The crude is heated by the heated sections surrounding the tubing and by the hot exhaust gases thus reducing the crude viscosity and preventing the building up of wax within the tubing. The catalyst bed may alternatively comprise a single layer of catalyst supporting particles attached to the outer surface of the production tubing string or selected sections thereof.

Abstract: A combustor for generating a mixture of steam and combustion gas is located downhole in an oil well, so that the mixture can be injected directly into the reservoir, to displace heavy oil from the reservoir. The combustion is built up in stages, with each stage supplying hot air to the following stage. The first stage comprises a catalytic heat exchanger, which preheats the incoming air. One side of the exchanger is coated with catalyst. On this side of the exchanger the preheated air burns a clean fuel, so that heat flows through the metal wall of the exchanger to preheat the incoming air. The heated air from the first stage is used to ignite and burn a heavy fuel such as crude oil, which is burned in the second stage and following stages.

Abstract: Disclosed is a method and apparatus for generating high pressure steam within a well bore for facilitating recovery of hydrocarbon deposits. The steam vapor generator is constructed for receiving high pressure water, fuel and oxidant in a downhole position for select mixing and combustion. High pressure water is received around a combustion chamber in an annular configuration and heated through a thermal wall region forming a lower portion thereof. The combustion chamber utilizes the heat energy of radiation to heat the water in the annular sleeve to the point of steam. The water sleeve further includes orifices for egress of the steam and a plurality of vent tubes within the water sleeve. The vent tubes extend substantially the length of the sleeve for receiving excess water vapor and/or undissolved gases created from the heat of vaporization and out-gassing.

Abstract: An in situ process and ignition procedure are provided to retort oil shale which increases product yield and enhances uniformity of the flame front in an underground retort. In the process, a portion of the rubblized mass of oil shale is preheated with steam, nitrogen or some other inert gas, to at least the minimum oil shale ignition temperature and preferably retorted. Thereafter, the preheated oil shale is ignited with hot excess air or some other oxygen-containing gas above the maximum desired retorting temperature to establish a generally uniform flame front across the retort. In the preferred form, the preheating gas and oxygen-containing gas are introduced into the retort at different times from the same specially configured downhole burner.

Abstract: An oil recovery system comprising a downhole steam generator 24, a pump 32 and a turbine 36 operable by said steam generator 24 to drive said pump 32.

Abstract: An apparatus for downhole steam generation employing dual-stage preheaters for liquid fuel and for the water. A first heat exchange jacket for the fuel surrounds the fuel/oxidant mixing section of the combustor assembly downstream of the fuel nozzle and contacts the top of the combustor unit of the combustor assembly, thereby receiving heat directly from the combustion of the fuel/oxidant. A second stage heat exchange jacket surrounds an upper portion of the oxidant supply line adjacent the fuel nozzle receiving further heat from the compression heat which results from pressurization of the oxidant. The combustor unit includes an inner combustor sleeve whose inner wall defines the combustion zone. The inner combustor sleeve is surrounded by two concentric water channels, one defined by the space between the inner combustor sleeve and an intermediate sleeve, and the second defined by the space between the intermediate sleeve and an outer cylindrical housing.

Abstract: A pumping system (10) is disclosed for pumping a fluid (14) from within a borehole (12) to the surface. A combustion engine (18) is employed to drive a pump comprising a pump barrel (28) and an auger pump shaft (32). The pumped fluid is carried from the borehole in a fluid return tubing string (42) having a standing valve (44) therein to prevent backflow into the borehole. A fuel-air mixture is provided to the combustion engine (18) through a fuel-air tubing string (22). A byproduct of the combustion of the fuel-air mixture is heat. The combusted mixture is exhausted from the combustion engine (18) through an engine exhaust tubing string (60). The engine exhaust tubing string includes a heating coil portion (64) forming a heat exchanger to transfer heat from the combusted fuel-air mixture to the fluid (14) adjacent the inlet of the pump to reduce the viscosity of the fluid to enhance the efficiency of the pumping system.

Abstract: A catalytic combustor for generating a mixture of steam and combustion gas is located downhole in an oil well, so that the gas mixture can be injected directly into the oil reservoir to displace heavy oils from the reservoir. There can be a single stage of catalytic combustion, or there can be a stage of thermal combustion followed by a catalytic stage. In either case the purpose of the catalyst is to drive the combustion to completion so that the gas mixture contains no soot that would plug the face of the reservoir.

Abstract: An apparatus for generation of steam in a borehole for penetration into an earth formation wherein a spiral, tubular heat exchanger is used in the combustion chamber to isolate the combustion process from the water being superheated for conversion into steam. The isolation allows combustion of a relatively low pressure oxidant and fuel mixture for generating high enthalpy steam. The fuel is preheated by feedback of combustion gases from the top of the combustion chamber through a fuel preheater chamber. The hot exhaust gases of combustion at the bottom of the combustion chamber, after flowing over the heat exchanger enter an exhaust passage and pipe. The exhaust pipe is mounted inside the water supply line heating the water flowing into the heat exchanger. After being superheated in the heat exchanger, the water is ejected through an expansion nozzle and converts into steam prior to penetration into the earth formation.

Abstract: An apparatus for generation of steam in a borehole for penetration into an earth formation wherein feedback preheater means are provided for the fuel and water before entering the combustor assembly. First, combustion gases are conducted from the combustion chamber to locations in proximity to the water and fuel supplies. Secondly, both hot combustion gases and steam are conducted from the borehole back to the water and fuel supply. The water used for conversion to steam is passed in a countercurrent manner through a plurality of annular water flow channels surrounding the combustion chamber. In this manner, the water is preheated, and the combustion chamber is cooled simultaneously, thereby minimizing thermal stresses and deterioration of the walls of the combustion chamber. The water is injected through slotted inlets along the combustion chamber wall to provide an unstable boundary layer and stripping of the water from the wall for efficient steam generation.

Abstract: Apparatus and method for generation of steam in a borehole for penetration into an earth formation wherein a downhole oxidant compressor is used to compress relatively low pressure (atmospheric) oxidant, such as air, to a relatively high pressure prior to mixing with fuel for combustion. The multi-stage compressor receives motive power through a shaft driven by a gas turbine powered by the hot expanding combustion gases. The main flow of compressed oxidant passes through a velocity increasing nozzle formed by a reduced central section of the compressor housing. An oxidant bypass feedpipe leading to peripheral oxidant injection nozzles of the combustion chamber are also provided. The downhole compressor allows effective steam generation in deep wells without need for high pressure surface compressors. Feedback preheater means are provided for preheating fuel in a preheat chamber.

Abstract: A method for heat injection into a subterranean formation is provided. The method utilizes flameless combustion. The absence of a flame eliminates the flame as a radiant heat source and results in a more even temperature distribution throughout the length of the burner. Flameless combustion is accomplished by preheating the fuel and the combustion air to a temperature above the autoignition temperature of the mixture. Preheating hydrocarbon fuel requires the inclusion of a carbon formation suppressant such as carbon dioxide or steam to prevent carbon formation.