Abstract: An electrode well extending into a subterranean formation containing viscous hydrocarbons comprising a plurality of electrode tubes which are formed by extension of an elongated tube from the surface above the formation using a coiled tube injection unit or lowering the tubes on drill pipe, diverting the tubes radially outwardly from the wellbore into the formation and penetrating the formation with the electrode tubes using hydraulic jetting action by pumping fluid through the tubes during the insertion process. The tubes are installed axially spaced apart using respective tube guide members which are inserted into the wellbore and operate to form a curved path for diverting the tubes into the formation during the insertion process and for supporting the end of the tube after its insertion into the wellbore.

Abstract: A method for stimulating the production of hydrocarbonaceous fluid from a subterranean geologic formation in the earth during microwave heating of same wherein a portion of high electrical conductivity non-hydrocarbonaceous fluid present in the formation near the wellbore in which microwave heating is taking place is displaced away from the wellbore to substantially reduce the overall electrical conductivity of the formation and its contained fluids in a finite volume around the wellbore thereby increasing the effectiveness of the microwave heating in such finite volume and stimulating the movement of desired hydrocarbonaceous fluid in such finite volume for recovery purposes.

Abstract: A method for obtaining a hydrocarbon liquid from a hydrocarbon strata of an earth formation traversed by a borehole wherein the hydrocarbon strata is subjected to RF electromagnetic energy retorting by locating metal tubing formed in a predetermined manner in that portion of the borehole traversing the hydrocarbon strata. Additional metal tubing formed in a conventional manner is connected with the metal tubing located in the borehole traversing hydrocarbon strata so that together they form a production stream. The hydrocarbon liquid from the borehole may be pumped through the production stream to the surface of the earth formation.

Abstract: A slotted radiating unit is lowered into a well casing of limited cross section, and microwave energy is fed downwardly thereto via a transmission line also installed in the casing. Two embodiments of the radiating unit are disclosed, and two embodiments of the transmission line are also described. Depending upon the subterranean conditions, periods of on and off microwave propagation are sometimes employed; in some instances dual radio frequencies are utilized to enhance petroleum flow. Subsurface sensors are made use of to control the ground level radio frequency generator (or generators).

Abstract: In treating a well, automatically controlled measurements of temperature with depth within a subterranean interval which can be longer than hundreds of feet, deeper than thousands of feet and hotter than 600.degree. C., are made by extending a slender measuring means conduit through the well and the zone to be measured and arranging an electrically responsive temperature sensing means and a means for spooling a metal sheathed telemetering cable for the electrical temperature responses so that the sensing means is lowered through the measuring conduit by gravity and raised within the conduit by spooling and temperatures and/or temperature with depths are measured while the sensing means temperature is substantially in equilibrium with the temperatures in the interval being measured.

Abstract: Electrical current is caused to flow between an electrode well located in an aquafer above viscous hydrocarbon-bearing formation and an electrode well located in an aquafer below the hydrocarbon-bearing formation. The electrical current thereby tends to spread out in a broad plate-like configuration from each electrode well. This increases the area of the hydrocarbon-bearing formation through which current is flowed, thereby extending the region which is heated by electrical dissapation. The nature of the aquafers and their location eases and resolves much of the adverse vaporization and pressure buildup that occurs in other systems. This also allows water to be readily injected to into or produced from the electrode wells to further control vaporization and pressure buildup without adversely affecting gravity drainage, other drive mechanisms or injection programs operating within the hydrocarbon-bearing formation. In addition, this enables the electrode wells to be used in a more continuous manner.

Abstract: A downhole tool for use in recovering a first fluid from a mixture of fluids in a confined space, comprising a collector for the mixture, separator means for receiving the mixture from the collector and for separating the first fluid from the mixture, means for expanding the volume of the residual fluid of the mixture, and means for feeding the expanded fluid into the confined space thereby to provide sufficient pressure within the confined space to force uncollected mixture into the collector and then to the separator means.

Abstract: The system and the method of the present invention for the in-situ retorting of a hydrocarbon stratum, having a borehole traversing it, with electrical energy at a radio frequency (hereinafter referred to as rf energy) includes apparatus for conducting the rf energy from an rf energy source down a borehole. The apparatus has an outer conductor and inner conductor. A first plurality of electrodes is inserted into the hydrocarbon stratum. A second plurality of electrodes spatially related to the first plurality of electrodes, is also inserted into a hydrocarbon stratum. A first conductive device makes contact between the outer conductor of the apparatus and the first plurality of electrodes. A second conductive device makes electrical contact between the inner conductor of the apparatus and the second plurality of electrodes so that when the rf source provides the rf energy, the rf energy is applied acorss that portion of the hydrocarbon stratum between the two pluralities of electrodes.

Abstract: A system for in situ heating of oil shale by radiating electromagnetic wave energy from a dipole radiator positioned beneath an overburden in a body of oil shale. Radio frequency power is supplied from the surface through a transmission line to the radiator dipoles whose diameters are substantially greater than the spacing between the transmission line conductors. The dipole radiator is center fed by the transmission line through a reentrant choke structure substantially filled with a solid dielectric medium and concentric with one of said dipole elements.

Abstract: A method and apparatus is applicable to in situ heating of oil shale or tar sand. The heating is by radio frequency that is applied down hole by a central conductor that extends beyond a coaxial shielding conductor to form the antenna or applicator. Encroachment by the heated formation is overcome by applying motion to the central conductor to remove encroaching formations.

Abstract: A well heater is installed in a well by spooling electrical cable assemblies for heating and supplying power, in proper sequence, on at least one spooling means, unspooling them and attaching them to a heat- and tension-stable support means as the resulting assembly is drawn into the well by a weight attached to the support means.

Abstract: Long intervals of subterranean earth formations are heated at high temperatures for long times with an electrical heater containing spoolable, steel sheathed, mineral insulated cables which have high electrical conductivities, enabling them to heat the earth formations at a substantially uniform rate of more than about 100 watts per foot at temperatures between about 600.degree. and 1000.degree. C., with a pattern of localized electrical resistances which are correlated with the heat conductivities of the earth formations and the heat stabilities of materials providing power and support for the heater.

Abstract: A downhole thermoacoustic device comprises a heater with a terminal chamber, connected to a source or radiator of acoustic oscillation, including a hollow housing having mounted therein a longitudinal shaft carrying coils with cores in the form of a plurality of flat rings of a magnetostrictive material, operable as the active elements adapted to generate acoustic oscillation. Accommodated intermediate the coils is a member for focusing the acoustic field, in the form of a sleeve, while the longitudinal shaft carries a tube-shaped reflector of acoustic oscillation internally of the core of each coil. The top and bottom portions of the hollow housing of the radiator of acoustic oscillation have mounted therein damping elements including sleeves of a resilient material, while a heat-insulating member including a sleeve with a fluted surface is provided intermediate the terminal chamber of the heater and the hollow housing of the radiator.

Abstract: A waveguide structure is emplanted in the earth to bound a particular volume of an earth formation with a waveguide structure formed of respective rows of discrete elongated electrodes wherein the spacing between rows is greater than the distance between electrodes in a respective row and in the case of vertical electrodes substantially less than the thickness of the hydrocarbonaceous earth formation. Electrical power at no more than a relatively low frequency is applied between respective rows of the electrodes to deliver power to the formation while producing relatively uniform heating thereof and limiting the relative loss of heat to adjacent barren regions to less than a tolerable amount. At the same time the temperature of the electrodes is controlled near the vaporization point of water thereat to maintain an electrically conductive path between the electrodes and the formation.

Abstract: A method of removing paraffin build up from an oil well which includes determining the location of a cooler portion of the oil well at which paraffin build up occurs, introducing an inductance heating element down into the annular space between the oil well tubing and the oil well casing, positioning the inductance heating element in the vicinity of the cooler portion and inductance heating the inside surface of the oil well tube to at least the temperature about that of the melting point of paraffin. Preferably, the inside surface of the tube is heated on the down stroke of the oil well sucker rod and at the start of the sucker rod up stroke in order to strip the paraffin from the tubing. The outside surface of the sucker rod is heated on its up stroke and the inductance heater has multiple bands of coil to heat the same general area of the sucker rod as it travels.

Abstract: Water is vaporized in an annular upper region of a subsurface formation into which borehole extends from the surface. This creates a substantially nonconducting dielectric in such region extending outwardly from the borehole. Such vaporization is preferably achieved by the application of electrical power to an electrode disposed in the borehole. Liquid is produced through the borehole from a lower region of the formation to cool the lower region near the borehole and maintain an electrically conductive path between the formation and the electrode in such lower region through which electrical power is applied to the formation.

Abstract: A method of heating an oil shale formation to produce shale oil includes radiating RF energy into the oil shale formation for a predetermined first time interval from a first borehole which penetrates said oil shale formation. Shale oil is produced when available during said first time interval from a second borehole penetrating said oil shale formation which is a predetermined distance from the first borehole. During a predetermined second time interval, RF energy is again radiated into the oil shale formation from the second borehole while shale oil is produced from the first borehole during the second time interval.

Abstract: A single well method and apparatus for electrically applying heat and stimulating is comprised of a relatively lower surface area formation electrode and relatively high surface area overburden electrode extending downward into the borehole past low resistivity water zones. This long overburden electrode may be formed of nonmagnetic metal to reduce hysteresis losses in the electrode. This improved single well system causes most of power to be dissipated in the oil pay zone and thereby renders single well production economical.

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: A system and method provide for preferential in situ heating of earth formations. A plurality of elongated conductive electrodes are emplaced in earth formations in respective spaced rows bounding a particular volume of the earth formations and forming a transmission line, preferably a triplate line, extending in the direction of the electrodes with the particular volume of the earth formations providing a dielectric medium between respective rows of electrodes. Electromagnetic energy is supplied to the transmission line at a frequency at which the spacing between respective rows is less than about twice the skin depth at the frequency of the applied energy. Reactance means are disposed along respective electrodes to provide predetermined effective transmission line characteristics to develop a predetermined heating pattern in the earth formations. The reactance means may be reactances disposed discretely between sections of respective electrodes.

Abstract: Apparatus and a method of producing fluid organic products from kerogen in situ in a body of oil shale by the application of alternating electric fields having a frequency between 100 kilohertz and 100 megahertz to heat the kerogen in the oil shale to a temperature in the range of 200.degree. C. to 360.degree. C. and to maintain the kerogen in this temperature range for a period of time sufficient to convert a substantial portion of the kerogen in oil shale to fluid organic products which may be collected through passages produced in the oil shale formation by flowing to a well bore having a collection sump.

Abstract: The effects of radio frequency electric field peaking in the earth formations surrounding a conductor excited by radio frequency energy in the controlled in situ heat processing of hydrocarbonaceous earth formations are mitigated by providing an inert buffer region around the conductor to which radio frequency electromagnetic energy is supplied to produce an electric field within the earth formations. A portion of the earth formations is removed to accommodate insertion of the conductor at a desired location in the earth formations and to provide a buffer region between the conductor and the surrounding earth formations. The conductor is supported at the desired location in spaced relationship to the surrounding earth formations, the buffer region encompassing the principal region of the electric field enhancement region around the conductor where the probability of breakdown in the earth formations over the period of application of the radio frequency energy would be above a tolerable level.

Abstract: The disclosure relates to a technique for controlled or uniform temperature heating of a volume of hydrocarbonaceous material in an earth formation employing conductor arrays, inserted in the formation, for applying radio frequency energy to the formation. The number and spacing of conductors in the arrays are selected to provide a concentration of electric field intensity at the extremities of the volume to facilitate controlled or uniform temperature heating of the volume. The arrangement compensates for temperature variations across the volume caused by heat flow within the volume and heat loss to the surrounding formation.

Abstract: The present invention relates to a method and device for promoting oil recovery.The device according to the invention for promoting the recovery of oil contained in a reservoir formation from a well equipped with a casing, comprises an anode which is placed at the bottom of the well, below said reservoir formation, in an electro-conductive liquid, and which is connected to the positive terminal of a direct or pulsed source of unidirectional voltage. Said casing is connected to the negative terminal of said source. The method consists in applying a unidirectional voltage for periods varying between several days and several months and alternating with OFF-period (when no voltage is applied).

Abstract: A method for enhancing the recovery of oil from underground formations includes alternately using a single bore hole as an electrode well and a producing well by placing a first electrode in electrical contact with the oil-bearing formation through the bore hole and passing electrical current through the oil-bearing formation which has been infused with an aqueous electrolytic liquid to a second larger electrode in electrical contact with earth material, and creating sufficient heat and current density proximate the first electrode to precipitate a local exothermic electrochemical reaction producing hot gases which pressurize the formation, thin the oil and break the oil out of the formation matrix. After the formation has been adequately conditioned by the reaction, oil is produced from the bore hole where the beneficial aspects of the reaction are greatest. Preferably, the electrical current employed is alternating current having a substantially rectangular waveform.

Abstract: The process and apparatus for extracting the products of kerogen in situ from an oil shale body by supplying energy selectively to the kerogen by high frequency electric fields in the frequency range between 100 kilohertz and 1000 megahertz at an intensity which heats the kerogen to a temperature range between 250.degree. C. and 500.degree. C. to allow pyrolysis of the kerogen prior to substantial heat transfer to the surrounding mineral portions of the oil shale. A plurality of groups of spaced radiators produce the electric fields for heating the kerogen. A dipole radiator in the subsurface formation is supplied with electromagnetic energy through a transmission line from an energy generator on the surface.

Abstract: A system and method for the controlled in situ heat processing of hydrocarbonaceous earth formations involves the application of electromagnetic energy at a selected frequency or at selected frequencies to a waveguide structure formed by electrodes bounding a particular volume of hydrocarbonaceous material. Terminating one end of the structure with different impedances at different times produces electric field standing waves of different respective phase at that end at a selected frequency. Two standing waves substantially 90.degree. out of phase in formations having relatively uniform dielectric properties result in substantially uniform application of heating power if the product of the amplitude-squared of the electric field standing wave and dwell time is substantially the same in each of the two modes. Feeding the line at both ends provides partial offset for attenuation. Various desired controlled heating patterns other than uniform may be effected by utilizing different dwell times or applied fields.

Abstract: A excitation apparatus is lowered through the casing of an oil well until it is submerged in oil. The apparatus includes a gas discharge tube which emits radiation, either ultraviolet or infra-red, into the surrounding oil. Next, another section of the excitation apparatus provides a mechanical energy input to the oil. The effect is to increase the pressure within the well and to cause the oil to flow more freely, thereby markedly increasing the productivity of the well after the treatment has been completed.

Abstract: An electrode device for electrically heating underground deposits of hydrocarbons in which an insulated pipe is disposed between an electrode and a main guide pipe. The two end portions of the insulated pipe are formed as flanges having outer circumferential surfaces counter tapered to diverge at a predetermined angle toward the end portions. Shock absorbers are disposed between fastening fixtures and the counter-tapered surfaces of the insulated pipe and the fastening fixtures are coupled to connectors on the main guide pipe and the electrode through bolts. If desired, the abutting surfaces of the main guide pipe and the electrode can be formed counter tapered similarly to the counter-tapered surfaces of the insulated pipe.

Abstract: The electrode of an electrode well is formed by inserting a heating device into the borehole and heating the surrounding formation to a temperature at which the hydrocarbon-containing material undergoes thermal cracking, resulting in a coke-like residue surrounding the heater. This conductive and permeable carbonized material serves as an electrode of enlarged radius for further electroheating of the formation.

Abstract: In a pair of electrode wells to be developed for injection and production wells for the electrothermal process for recovering heavy hydrocarbons, the electrodes are formed by inserting a heating device in each borehole and heating the surrounding formation to a temperature at which the hydrocarbon-containing material undergoes thermal cracking, resulting in a coke-like residue surrounding the heater. This conductive and permeable material serves as an electrode, for each well, by which the formation is heated. The heavy hydrocarbon material, such as bitumen found in tar sands, becomes mobile and can be recovered.

Abstract: An electrode unit for electrically heating underground hydrocarbon deposits having a main conduit pipe assembly, a cylindrical water pipe and an electrical conductor arranged coaxially with the electrical conductor disposed between the water pipe and the main conduit pipe assembly. The spaces between the main conduit pipe assembly and the cylindrical water pipe are filled with a solid insulating material, wherein it is not necessary to recirculate cooling oil through the assembly. Connectors are disposed for joining ends of adjacent main conduit pipe assemblies, ends of adjacent water pipes and electrical conductors. Preferably, the electrical conductor is made of a material such as a metal mesh which can stretch longitudinally.

Abstract: The method and improvement for recovery of hydrocarbons in situ from subterranean oil shale formations is disclosed by forming generally horizontal electrodes from the injection of molten metal into preheated or unheated fractures of the formation. A nonconductive spacing material is positioned in the casing of the bore hole between the electrodes. A fracture horizontally intermediate between the metallic electrodes is propped with a nonconductive granular material. Unterminated standing waves from a radio frequency (R.F.) generator are passed between the electrodes so as to heat the oil shale formation. The hydrocarbons in the formation are vaporized and are recovered at the surface by their migration through the intermediate fracture and tubing. By this method radial metallic electrodes can be formed at various depths throughout a subterranean oil shale formation so as to vaporize the hydrocarbons contained within the oil shale formation.

Abstract: A novel apparatus and method for time-domain tracking of high-speed chemical reactions. The apparatus of this invention includes a feedback system for controlling the RF frequency of an RF radiator system to thereby provide the optimum RF frequency for heating the reaction. The apparatus and method of this invention are particularly useful in the recovery of products from oil shale wherein the oil shale is heated by RF dielectric heating and the feedback system adjusts the RF frequency as the permittivity of the oil shale changes during the heating process.

Abstract: Apparatus for heating hydrocarbons, and the like, in an underground reservoir for the purpose of lowering the viscosity of the substance in the reservoir and facilitating the flow thereof has a flow channel arrangement disposable in a reservoir of the material to be treated for forming a flow path for a working fluid that is heated by a heating system associated with the flow channel arrangement. The heated working fluid is then discharged from the flow path and into the reservoir of material to be heated for the purpose of lowering the viscosity and improving the flowability of the material in the reservoir.The heating system includes an electrical resistance heating unit comprising an electrical circuit including at least one pair of opposed electrodes electrically connected in series and arranged along and partially forming the flow path for the working fluid, with the portion of the electrical circuit between the electrodes being completed through the working fluid.

Abstract: The disclosure relates to a technique for radio frequency heating of hydrocarbonaceous earth formations in which a high power radio frequency transmitter is impedance matched to a transmission line including a plurality of conductors at least partially embedded in the formation to be heated. The impedance matching may be effected by a "T" network having three variable reactances. In accordance with the teachings of the present invention, continuous variations of impedance, of the type encountered during the heating of the formation, may be matched in unambiguously defined Smith chart regions by varying two of the three reactances to minimize reflected power from the transmission line.

Abstract: A preheater is disclosed which can be inserted and withdrawn from a well tube defining a curved passage, without having its heating element damaged, by utilizing the flexibility of a spirally coiled structure having increased stability of shape and excellent capacity of restoring its original shape after elastic deformation.

Abstract: A method and apparatus for cleaning openings in a borehole casing, slotted liner, screen or the like, cleaning subsurface earth formations and/or stimulating the flow of fluids through subsurface earth formations surrounding a borehole in which a plasma is generated adjacent the area to be treated by the gasification and ionization of a gasifiable and ionizable material, such as, water, petroleum or similar fluids and/or solids, such as, a consumable metal wire, thereby creating an intense shock wave which passes into or through the material being treated. The plasma region is created by any means adapted to gasify and ionize the gasifiable and ionizable material, such as, a high voltage, high current electrical discharge of short duration.

Abstract: A method and apparatus for fracturing and/or heating subsurface formations wherein an alternating current electric field is produced in the frequency range between 100 kilohertz and 100 meghertz between electrodes spaced apart in the formation and a radio frequency generator supplying a voltage between said lines with suitable loading structures tuned to the frequency of the generator to resonate the electrodes as a parallel wire transmission line which is terminated in an open circuit and produces a standing wave having a voltage node at the end of the line.

Abstract: At least a portion of an oil-recovery well casing adjacent an oil-bearing earth formation is heated by the passing of an electrical current therethrough. The heated casing heats any oil entering therein. Paraffin found in the heated oil is thus maintained in a liquefied state thereby substantially reducing paraffin buildup in the oil-recovery well.

Abstract: A portion of an injection well adjacent an oil-bearing earth formation is sealed off by spaced-apart high-pressure-resistant plugs, and water is charged into the bore-hole space between the plugs at a sufficient rate to effect sustained water pressure in the range of from 400 to 25,000 psi. Under such pressure sufficient current is passed between two electrodes in the water to convert from 10 to 33 barrels of water per hour into steam.

Abstract: The process and apparatus for extracting the products of kerogen in situ from an oil shale body by supplying energy selectively to the kerogen by high frequency electric fields in the frequency range between 100 kilohertz and 1000 megahertz at an intensity which heats the kerogen to a temperature range between 250.degree. C. and 500.degree. C. to allow pyrolysis of the kerogen prior to substantial heat transfer to the surrounding mineral portions of the oil shale.

Abstract: A thermal recovery system for a subterranean well includes an electric heater located immediate the bottom of the well which cyclically receives electric power generated at the well surface. A pump directs a stream of pressurized fluid, such as water, through a conduit to a solenoid valve located at the bottom of the well. The solenoid valve senses electric power application relative to the heater and directs the stream of pressurized water to one of two fluid circuits. When electric power is supplied to the heater, the solenoid valve directs the fluid stream into the heater. The heater thermally stimulates the well and is cooled by the water which is heated and exhausted to thermally stimulate the well. When electric power is not supplied to the heater, the solenoid valve directs the pressurized water to a turbine for driving a production pump. In an alternate embodiment, both the heater and the production pump are operated continuously and the fluid stream is divided between the turbine and the heater.

Abstract: The present invention is directed to an apparatus for installing strain gages or other sensors-transducers in wellbores penetrating subterranean earth formations. The subject apparatus comprises an assembly which is lowered into the wellbore, secured in place, and then actuated to sequentially clean the wellbore or casing surface at a selected location with suitable solvents, etchants and neutralizers, grind the surface to a relatively smooth finish, apply an adhesive to the surface, and attach the strain gages or the like to the adhesive-bearing surface. After installing the condition-sensing gages to the casing or earth formation the assembly is withdrawn from the wellbore leaving the sensing gages securely attached to the casing or the subterranean earth formation.

Abstract: In situ shale oil recovery from oil shale deposits using radio frequency energy as a heat generator is facilitated by rubblizing the shale oil deposits before application of radio frequency energy.

Abstract: In one exemplar embodiment, method and apparatus include providing an electrode disposed in a plurality of insulated, spaced boreholes penetrating the oil formation. The plurality of electrodes in contact with a water electrolyte in the formation are connected to a source of AC electrical power for establishing a current flow between the spaced electrodes and through the oil bearing formation by means of the electrolyte. The electrodes are insulated from the earth structure surrounding the boreholes for preventing an electrical current path between the electrodes and the earth structure for isolating the electrical current path between the electrodes and the formation. When the AC current passing through the formation surpasses a minimum current density, AC disassociaton of the H.sub.

Abstract: A method and apparatus for the recovery of petroleum from petroleum impregnated media. The apparatus includes a microwave generator and a guide for directing microwaves to a microwave dispersing chamber for heating the media. The apparatus has a plurality of holes for the flow of heated petroleum into a petroleum chamber. The method of the invention includes inserting the apparatus into an opening in the media, dispersing microwaves into the media to heat it and recovering petroleum in the recovery chamber.

Abstract: A novel method for stimulating the flow of oil from the pay zone of a formation traversed by a bore hole which involves the conversion of liquid water into high pressure steam in situ in heat transfer proximity to the pay zone. A novel oil tool adapted to be lowered and suspended within the bore hole in proximity to the pay zone having an external elongated shell within which is contained means for the in situ generation of steam. The casing may be adapted to generate steam internally and allow that steam to pass through the shell and into contact with the pay zone at a predetermined high pressure, or to superheat highly pressurized water and allow it to pass through an orifice in the shell, at which time it immediately flashes to high pressure steam and disperses into the area of the pay zone. A novel electrical control system for the operation, regulation and malfunction-detection of the oil tool from the ground surface.

Abstract: The disclosure describes a technique for uniform heating of relatively large blocks of hydrocarbonaceous formations in situ using radio frequency (RF) electrical energy that is substantially confined to the volume to be heated and effects of dielectric heating of the formations. An important aspect of the disclosure relates to the fact that certain hydrocarbonaceous earth formations, for example raw unheated oil shale, exhibit dielectric absorption characteristics in the radio frequency range. In accordance with the system of the invention, a plurality of conductors are inserted in the formations and bound a particular volume of the formations. The phrase "bounding a particular volume" is intended to mean that the volume is enclosed on at least two sides thereof. Electrical excitation is provided for establishing alternating electric fields in the volume.

Abstract: The disclosure describes a technique for uniform heating of relatively large blocks of hydrocarbonaceous formations in situ using radio frequency (RF) electrical energy that is substantially confined to the volume to be heated and effects of dielectric heating of the formations. An important aspect of the disclosure relates to the fact that certain hydrocarbonaceous earth formations, for example raw unheated oil shale, exhibit dielectric absorption characteristics in the radio frequency range. In accordance with the system of the invention, a plurality of conductors are inserted in the formations and bound a particular volume of the formations. The phrase "bounding a particular volume" is intended to mean that the volume is enclosed on at least two sides thereof. Electrical excitation is provided for establishing alternating electric fields in the volume.