Abstract: Apparatus and method for heating and preventing freeze-off of wellhead equipment utilize radiant heat from a flameless heater to heat fluid in a heat exchanger, such as a tank or finned radiator. A pump is used to circulate the heated fluid through a conduit loop deployed in thermal contact with the equipment to be heated, such that the heat from the fluid is transferred to the equipment, maintaining it at sufficient temperature to prevent freeze-off. The apparatus and method may also be used for other purposes, such as for circulating heated fluid through a liquid-cooled engine to facilitate cold weather starting.

Abstract: A coal formation may be treated using an in situ thermal process. Hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat sources may be positioned within open wellbores in the formation.

Abstract: A closed loop heat transfer system located on the surface near the wellhead for transporting hot fluid through a tubing located in the annulus between the well casing and the outer surface of the production string. The tubing extends down along the production string to a coil submerged in the oil reservoir in the vicinity of the production pump and back to the surface for reheating and recirculation. The tubing provides heat transfer from the hot fluid to the production fluid, as well as the downhole pump and the region of the oil reservoir surrounding the pump. The system is preferably operated to transfer enough heat to the oil to prevent paraffins from coagulating and forming deposits on the production string or sucker rods, if used. The higher temperature lowers the viscosity of the oil and increases oil production.

Abstract: The invention relates to a device for the elimination of gas or paraffin hydrate deposits that form in well drilling equipment or hydrocarbon production and transportation equipment through the use of a reactant that is likely to decompose at high temperatures.

Abstract: A method for retarding temperature loss of fluid being produced in a well employs a fluid of low thermal conductivity in the tubing annulus. The tubing annulus extends between the production casing and the production tubing. It extends from a packer at the lower end of the tubing annulus to a wellhead. The fluid in one case is low density gas created by a partial vacuum. A vacuum is drawn on the tubing annulus to reduce the air density, which in turn reduces the amount of heat that convection currents can carry. In another example, the tubing annulus fluid is viscous hydrocarbon liquid. The hydrocarbon liquid also has a low thermal conductivity. Heat is supplied to the fluids being produced through the tubing annulus by a heater cable that extends into the well.

Abstract: A system for heating or cooling a wellhead, the system including a header in fluid communication via a pipe with a wellhead so that header heat transfer fluid is flowable from the header to the wellhead and back to the header, an earth heat exchange system with earth heat exchange fluid flowable therethrough to provide heat exchange between the earth heat exchange fluid and the earth, and the earth heat exchange fluid flowable in heat exchange relation to heat or cool the wellhead.

Abstract: A combustor method and apparatus is provided. The method utilizes flameless combustion with one or more of three improvements to enhance ignition of the flameless combustor. A catalytic surface can be provided within a combustion chamber to provide flameless combustion at least in the vicinity of the catalytic surface at a temperature that is much lower than the autoignition temperature of fuel in air without the presence of the catalytic surface. Nitrous oxide or supplemental oxygen may also be used as an oxidant either instead of air or with air to reduce ignition temperatures. Further, electrical energy can be passed through the fuel conduit, raising the temperature of the conduit to a temperature above which the fuel will ignite when combined with the oxidant.

Abstract: Material is thermally extracted from an underground formation with the aid of heat supplied by electrical resistance heaters (21) or by tubing (5, 6) serving as such, or by heated fluid conveyed downhole in pipes (12), which may serve as electrical conductors, or as resistance heaters, or which may be heated downhole. The fluid may be circulated upwardly after passage through a downhole pump unit where the fluid is suitable.

Abstract: A down-hole oil well heater for improved recovery of oil includes a heating element comprising a sheet of electrically conductive paper which generates heat as a result of resistance to current flow therethrough and spaced apart, primary conductor elements preferably in the form of thin metal strips attached, as by sewing, to the conductive paper to provide uniform distribution of current flow through the paper from one conductor element to the other. Secondary conductor elements are electrically connected to said primary conductor elements and controller means are electrically connected to such secondary conductor elements for controlling the flow of electricity to the electrically conductive paper. The heating element covers a portion of conventional oil well tubing and is sandwiched between layers of electrically nonconductive, insulating material.

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: A method and apparatus are provided for the recovery of a heavy oil, contained in an outcropping formation, without any significant adverse environmental impact. Broadly, the invention comprises indirectly heating an oil containing formation to reduce the viscosity of the oil therein and concurrently thermally insulating an upper portion of the well, extending into the formation, to eliminate any increased seepage of oil from the formation to the surface.

Abstract: A method of producing fluids from subterreanean reservoirs containing hydrogen sulphide and especially those reservoirs where elemental sulphur or hydrogen polysulphides are present. The method describes the use of a jet pump, chemical injection, and downhole electrical heaters to prevent the deposition of elemental sulphur within the production tubulars of wells penetrating such reservoirs by raising the pressure, temperature, and sulphur solvency of fluids being produced up these wells. In this way, subterranean reserves of sulphur and hydrogen sulphide which were previously unproducible or too expensive to produce can be commercially exploited.

Abstract: A housing surrounds a portion of a tubular member forming a combustion chamber in the annulus between the housing and the tubular member. The housing has an upper end and a lower end with a port for the passage of hot gases. The tubular member has a port at a lower end portion. The tubular member and housing are located in a borehole and oxygen and hydrogen are injected into the chamber to form a combustible mixture which is ignited and burned to form combustion gases for flow through the port of the housing into the borehole. Steam is injected through the tubular member for cooling the housing and the combustion gases. After a period of time, the injection of the oxygen, hydrogen and steam is terminated and a pump is lowered into the tubular member for pumping fluids in the borehole upward through the tubular member to the surface. Instead of steam, an excess of hydrogen may be injected into the combustion chamber for cooling purposes.

Abstract: A downhole heating generator for producing steam or hot water in oil wells to aid in the recovery of oil includes an elongated cylindrical housing suspended by a cable within the tube string of an oil well bore at the level of a geological formation to be heated. The housing has a closed bottom forming a container continously receiving water through a hose from a ground level source and contains a pair of electrode rods, preferably of carbon, mounted in end-to-end spaced aligned relationship and immersed at least partially in the water received in the housing for boiling the water and/or generating steam. The electrodes are connected to a ground level electrical transformer and are arranged to be capable of being energized at at least 2300 volts without arcing therebetween. The steam or hot water is discharged from the housing through an upper exit opening and is directed through openings in the tube string to the geological formation to be heated.

Abstract: A split-stream method and apparatus for preventing the accumulation of liquids, such as water or oil, in subterranean gas wells having low shut-in bottom hole pressures is provided. A compressor whose capacity can be less than the theoretical adiabatic horsepower for full wellhead depletion, is used to remove a two-phase liquid-gas mixture through a secondary fluid transmission conduit. Production of dry gas in larger quantities through a primary production conduit is then possible since liquids cannot accumulate to kill the well. An optional mechanism for initiating production in very low pressure wells and a means of preventing the buildup of paraffin is also described.

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 drill string working tool is provided that may be releasably engaged to and removed from a drill string member. The tool, such as a cylindrical stabilizer body, is positioned around a cylindrical drill string member, the inner diameter of the stabilizer body being greater than the outer diameter of the drill string member, so as to provide an annular cavity between the stabilizer body and the drill string member. A heating element disposed within a protective outer sheath is mounted axially along the inner surface of the stabilizer body. For installation, a low melting point solid material such as zinc or a zinc alloy is poured in to substantially fill the annular cavity. The stabilizer compression preloads the zinc onto the drill string member, and thus the stabilizer body is non-rotatably attached to the drill string member. For removal, the low melting point fill material is removed from the annular cavity by remelting with the interior heating element and pouring out the fill material.

Abstract: This invention relates to a system for controlling wax formation in oil wells using a thermal syphon wherein a confined annular space between the production tube and the oil string casing is provided by means of a plug, or "packer", installed at a point well below the level at which solid waxes begin to deposit out of the exiting crude oil and a plug, or "packer", installed above the point at which waxes would otherwise stop depositing out of the exiting crude oil and thereafter filling the confined annulus with a fluid working medium. The quantity and properties of the fluid working medium are arranged such that the medium is vaporized at the lower extremeties of the confined annulus and condensed on the surfaces of the upper regions of the confined annulus, particularly in the zone of wax deposition.

Abstract: A method and apparatus for making holes in coal seams in a coal mining system in which hot working gas is employed to impinge on the coal under high pressure and speed in order to disintegrate it and particularly for making inclined or horizontal holes which connect vertical drill holes which lead from the surface to the coal seam and through which the medium for gasifying the coal underground is blown in. The vertical drill holes which lead from the coal seam to the surface are used for blowing out gasification gases which are produced by the operation as well as for delivering the hot working gas. With the method of the invention, a gasification medium of high temperature and pressure is advantageously produced directly at the locations where the disintegrated coal is gasified, the disintegrated coal being formed by a rocket combustion process.

Abstract: In order to prevent freezing of the input lift gas in an oilwell in which gas under pressure is used to lift the well fluids, a heat exchanger is provided which serves to heat the input gas from the warm well fluids. The heat exchanger includes an outer casing and a coaxial tubing which is in line with the well fluid flow. The casing is sealed, and the tubing within the casing is provided with openings which permit the circulation of well fluids in the space between the casing inner wall and the tubing. Relatively small stainless steel tubing is spirally wrapped, in two spaced apart sections, around the tubing within the casing, and access parts are provided to permit the passage of input lift gas through the wrapped tubing prior to its injection into the well. The two wrapped tubing sections are coupled by a gas flow control valve external to the casing.

Abstract: Recovery of viscous petroleum such as from thick tar sands is assisted using a closed-loop flow path formed in a well by concentric casing and tubular members extending from the earth's surface through a substantial portion of the formation for conducting hot fluid to reduce the viscosity of the petroleum in the formation to develop a potential passage in the formation outside the flow path into which a drive fluid is injected to promote movement of the petroleum to the well for production up a production flow line extending up the interior of the tubular member.