Abstract: A technique is provided to model a heat penetration profile for various targets which are non-planar or three-dimensionally shaped targets for use in a heating system. The relative volume of material that is irradiated at various depths may have an impact on the absorbed heat profile through the target. For example, a hollow cylindrical product has substantially more material per micro-meter near the outside diameter than it does near the inside diameter. Accordingly, the thickness of the wall or the diameter of the hollow inside the cylinder, as well as the outer diameter of the cylinder, have a substantial impact on the ultimate heat profile through the wall.

Abstract: A heating system for a subsurface formation includes a conduit located in a first opening in the subsurface formation. Three electrical conductors are located in the conduit. A return conductor is located inside the conduit. The return conductor is electrically coupled to the ends of the electrical conductors distal from the surface of the formation. Insulation is located inside the conduit. The insulation electrically insulates the three electrical conductors, the return conductor, and the conduit from each other.

Abstract: A radio frequency heater is disclosed including a vessel for containing material to be heated and a radio frequency radiating surface. The vessel has a wall defining a reservoir. The radio frequency radiating surface at least partially surrounds the reservoir. The radiating surface includes two or more circumferentially spaced petals that are electrically isolated from other petals. The petals are positioned to irradiate at least a portion of the reservoir, and are adapted for connection to a source of radio frequency alternating current. A generally conical tank or tank segment having a conically wound radio frequency applicator is also contemplated. Also, a method of heating an oil-water process stream is disclosed. In this method a radio frequency heater and an oil-water process stream are provided. The process stream is irradiated with the heater, thus heating the water phase of the process stream.

Abstract: Method and system for direct electric heating of a pipeline to contribute to removal or hindrance of plugs of ice and optionally hydrates, distinguished in that heating takes place to a temperature above the ice melting point, but below the hydrate melting point.

Abstract: A system for heating a hydrocarbon containing formation includes a heater having an elongated ferromagnetic metal heater section. The heater is located in an opening in a formation. The heater section is configured to heat the hydrocarbon containing formation. The exposed ferromagnetic metal has a sulfidation rate that goes down with increasing temperature of the heater, when the heater is in a selected temperature range.

Abstract: A system used to heat a subsurface formation includes an elongated heater at least partially located in an opening in a hydrocarbon containing layer of the formation. The opening extends from the surface of the formation through an overburden section of the formation and into the hydrocarbon containing layer of the formation. The elongated heater includes an electrical conductor, an insulation layer at least partially surrounding the electrical conductor, and an electrically conductive sheath at least partially surrounding the insulation layer. The elongated heater tapers from a larger thickness at a first end of the heater to a smaller thickness at a second end of the heater. The first end is at or near the junction between the overburden section and the hydrocarbon containing layer and the second end is further into the hydrocarbon containing layer.

Abstract: A method for making a coiled insulated conductor heater to heat a subsurface formation includes pushing the insulated conductor heater longitudinally inside a flexible conduit using pressure. One or more cups are coupled to the outside of the insulated conductor heater. The cups maintain at least some pressure inside at least a portion of the flexible conduit as the insulated conductor heater is pushed inside the flexible conduit. The flexible conduit and the insulated conductor heater are coiled onto a coiled tubing rig.

Abstract: Certain embodiments provide a heater. The heater includes a ferromagnetic member. The heater also includes an electrical conductor electrically coupled to the ferromagnetic member. The electrical conductor is configured to conduct a majority of time-varying electrical current passing through the heater at about 25° C. The heater is configured to provide a first heat output below the Curie temperature of the ferromagnetic member. The heater is configured to automatically provide a second heat output approximately at and above the Curie temperature of the ferromagnetic member. The second heat output is reduced compared to the first heat output.

Abstract: An apparatus and method for quickly and effectively drying ground surfaces are disclosed and claimed. The invention has particular utility in the drying of a race track surface. The invention consists of a means for blowing air upon the surface, a means for heating the air and a means for moving the apparatus with respect to the surface to provide flexibility and control in the degree of drying/heating performed. The apparatus and method may be applied to a variety of surfaces including earthen (dirt) surfaces, concrete and asphalt. One of the objectives of the device is to enable the drying of a track surface such that the surface will not be damaged by overheating which can otherwise occur with other track drying devices applied to an asphalt surface in particular. The design of the invention makes specific use of enhanced turbulent air flow at the surface in order to improve performance over a purely laminar air flow.

Abstract: A heater system may include an alternating current supply and an electrical conductor. An alternating current may be applied to one or more electrical conductors at a voltage above about 200 volts. The electrical conductors may be located in a formation. The electrical conductors may provide an electrically resistive heat output upon application of the alternating electrical current. At least one of the electrical conductors may include an electrically resistive ferromagnetic material. An electrical conductor may provide a reduced amount of heat above or near a selected temperature. Heat may be allowed to transfer from an electrical conductor to a part of the formation.

Abstract: A system for treating a hydrocarbon containing formation is described. The system includes two or more groups of elongated heaters. The group includes two or more heaters placed in two or more openings in the formation. The heaters in the group are electrically coupled below the surface of the formation. The openings include at least partially uncased wellbores in a hydrocarbon layer of the formation. The groups are electrically configured such that current flow through the formation between at least two groups is inhibited. The heaters are configured to provide heat to the formation.

Abstract: A heater may include an electrical conductor. Applying alternating current to the electrical conductor may resistively heat the electrical conductor. The electrical conductor may include an electrically resistive ferromagnetic material. The ferromagnetic material may at least partially surround a non-ferromagnetic material. The heater may provide a reduced amount of heat above or near a selected temperature. An electrical insulator may at least partially surround the electrical conductor. A sheath may at least partially surround the electrical insulator.

Abstract: A heater is described. The heater includes a ferromagnetic conductor and an electrical conductor electrically coupled to the ferromagnetic conductor. The ferromagnetic conductor is positioned relative to the electrical conductor such that an electromagnetic field produced by time-varying current flow in the ferromagnetic conductor confines a majority of the flow of the electrical current to the electrical conductor at temperatures below or near a selected temperature.

Abstract: A heater system may include an alternating current supply and an electrical conductor. Alternating current may be applied to one or more electrical conductors at a frequency between about 100 Hz and about 1000 Hz. The electrical conductors may be located in a formation. The electrical conductors may resistively heat upon application of the alternating electrical current. At least one of the electrical conductors may include an electrically resistive ferromagnetic material. The electrical conductor may provide a reduced amount of heat above or near a selected temperature. Heat may transfer from the electrical conductor to a part of formation.

Abstract: Systems and methods are described for heating a subsurface formation. Alternating electrical current may be applied to one or more electrical conductors. The electrical conductors may be located in a subsurface formation. The electrical conductors may provide an electrically resistive heat output upon application of the alternating electrical current. At least one of the electrical conductors may include an electrically resistive ferromagnetic material. The electrical conductor may provide a reduced amount of heat above or near a selected temperature. Heat may be allowed to transfer from the electrical conductor to a part of the subsurface formation.

Abstract: A heating system for a subsurface formation includes an elongated electrical conductor located in the subsurface formation. The electrical conductor extends between at least a first electrical contact and a second electrical contact. A ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300° C.

Abstract: A system for heating a subsurface formation is described. The system includes a plurality of elongated heaters located in a plurality of openings in the formation. At least two of the heaters are substantially parallel to each other for at least a portion of the lengths of the heaters. At least two of the heaters have first end portions in a first region of the formation and second end portions in a second region of the formation. A source of time-varying current is configured to apply time-varying current to at least two of the heaters. The first end portions of at least two heaters are configured to have substantially the same voltage applied to them. The second portions of at least two heaters are configured to have substantially the same voltage applied to them.

Abstract: A system for heating a subsurface formation is described. The system includes an elongated heater in an opening in the formation. The elongated heater includes two or more portions along the length of the heater that have different power outputs. At least one portion of the elongated heater includes at least one temperature limited portion with at least one selected temperature at which the portion provides a reduced heat output. The heater is configured to provide heat to the formation with the different power outputs. The heater is configured so that the heater heats one or more portions of the formation at one or more selected heating rates.

Abstract: A system for treating a hydrocarbon containing formation is described. The system includes two or more groups of elongated heaters. The group includes two or more heaters placed in two or more openings in the formation. The heaters in the group are electrically coupled below the surface of the formation. The openings include at least partially uncased wellbores in a hydrocarbon layer of the formation. The groups are electrically configured such that current flow through the formation between at least two groups is inhibited. The heaters are configured to provide heat to the formation.

Abstract: Systems, methods, and heaters for treating a subsurface formation are described herein. At least one system for providing power to one or more subsurface heaters is described herein. The system may include an intermittent power source; a transformer coupled to the intermittent power source, and a tap controller coupled to the transformer. The transformer may be configured to transform power from the intermittent power source to power with appropriate operating parameters for the heaters. The tap controller may be configured to monitor and control the transformer so that a constant voltage is provided to the heaters from the transformer regardless of the load of the heaters and the power output provided by the intermittent power source.

Abstract: A system for heating a subsurface formation is described. The system includes a first elongated heater in a first opening in the formation. The first elongated heater includes an exposed metal section in a portion of the first opening. The portion is below a layer of the formation to be heated. The exposed metal section is exposed to the formation. A second elongated heater is in a second opening in the formation. The second opening connects to the first opening at or near the portion of the first opening below the layer to be heated. At least a portion of an exposed metal section of the second elongated heater is electrically coupled to at least a portion of the exposed metal section of the first elongated heater in the portion of the first opening below the layer to be heated.

Abstract: A system for treating a hydrocarbon containing formation is described. The system includes two or more groups of elongated heaters. The group includes two or more heaters placed in two or more openings in the formation. The heaters in the group are electrically coupled below the surface of the formation. The openings include at least partially uncased wellbores in a hydrocarbon layer of the formation. The groups are electrically configured such that current flow through the formation between at least two groups is inhibited. The heaters are configured to provide heat to the formation.

Abstract: A heating system for a subsurface formation is described. The heating system includes a first heater, a second heater, and a third heater placed in an opening in the subsurface formation. Each heater includes: an electrical conductor; an insulation layer at least partially surrounding the electrical conductor; and an electrically conductive sheath at least partially surrounding the insulation layer. The electrical conductor is electrically coupled to the sheath at a lower end portion of the heater. The lower end portion is the portion of the heater distal from a surface of the opening. The first heater, the second heater, and the third heater are electrically coupled at the lower end portions of the heaters. The first heater, the second heater, and the third heater are configured to be electrically coupled in a three-phase wye configuration.

Abstract: A heating and distributed-temperature-sensor cable permanently fixed in a wellbore that permits known amounts of heat to be introduced to subsurface formations and improved temperature measurement thereof. The heat is introduced into a target zone of the wellbore by forming the cable in two sections: an upper section that carries an electrical current without generating significant amounts of heat, and a lower section that generates heat from the electrical current. Continuous distributed-temperature-sensing is performed through measuring various scattering mechanism in optical fibers that run the length of the cable.

Abstract: Heaters for treating a subsurface formation are described herein. Such heaters can be obtained by using the systems and methods described herein. The heater includes a heater section including iron, cobalt, and carbon. The heater section has a Curie temperature less than a phase transformation temperature. The Curie temperature is at least 740° C. The heater section provides, when time varying current is applied to the heater section, an electrical resistance.

Abstract: Systems, methods, and heaters for treating a subsurface formation are described herein. Systems and methods for making heaters are described herein. At least one heater includes a ferromagnetic conductor and an electrical conductor. The electrical conductor is electrically coupled to the ferromagnetic conductor. The heater provides a first amount of heat at a lower temperature. The heater may provide a second reduced amount of heat when the heater reaches a selected temperature, or enters a selected temperature range, at which the ferromagnetic conductor undergoes a phase transformation.

Abstract: A system for heating a hydrocarbon containing formation is described. A conduit may be located in an opening in the formation. The conduit includes ferromagnetic material. An electrical conductor is positioned inside the conduit, and is electrically coupled to the conduit at or near an end portion of the conduit so that the electrical conductor and the conduit are electrically coupled in series. Electrical current flows in the electrical conductor in a substantially opposite direction to electrical current flow in the conduit during application of electrical current to the system. The flow of electrons is substantially confined to the inside of the conduit by the electromagnetic field generated from electrical current flow in the electrical conductor so that the outside surface of the conduit is at or near substantially zero potential at 25° C. The conduit may generate heat and heat the formation during application of electrical current.

Abstract: A well bore fluid is heated to prevent paraffin build-up or lower the viscosity of asphaltenic crude in the production line by an electrical heating element lowered into a pre-determined subterranean location. The heating element is controlled by a control unit that is connected to a temperature sensor and a pressure sensor, which detects temperature and pressure in the vicinity of the heating element and modifies an electric power source to deliver sufficient electric power to the electric heating element to keep the paraffin or other alkanes in a liquefied state. By modifications, the same heater can be used to generate steam in a well bore for the same purposes or to heat oil in a tank battery to prevent solidification of high molecular weight constituents in the crude.

Abstract: A down hole heating system for use with oil and gas wells which exhibit less than optimally achievable flow rates because of high oil viscosity and/or blockage by paraffin (or similar meltable petroleum byproducts). The heating unit the present invention includes shielding to prevent physical damage and shortages to electrical connections within the heating unit while down hole (a previously unrecognized source of system failures in prior art systems). The over-all heating system also includes heat retaining components to focus and contain heat in the production zone to promote flow to, and not just within, the production tubing.

Abstract: Certain embodiments provide a heating system configured to heat at least a part of a subsurface formation. The system includes an electrical power supply. A heater section includes one or more electrical conductors electrically coupled to the electrical power supply. The heater section is configured to be placed in an opening in the formation. At least one of the electrical conductors includes ferromagnetic material. The heater section provides a first heat output when time-varying electrical current is applied to the heater section below a selected temperature, and provides a second heat output approximately at and above the selected temperature during use. The second heat output is reduced compared to the first heat output. The system is configured to allow heat to transfer from the heater section to a part of the formation. The system is configured to allow a frequency of the applied time-varying electrical current to be varied.

Abstract: Certain embodiments provide a system configured to heat a subsurface formation. The system includes an electrical power supply. A heater section includes one or more electrical conductors electrically coupled to the electrical power supply. At least one of the electrical conductors includes ferromagnetic material. The heater section provides a first heat output when time-varying electrical current is applied to the heater section below a selected temperature, and a second heat output approximately at and above the selected temperature during use. The second heat output is reduced compared to the first heat output. The system is configured to allow heat to transfer from the heater section to a part of the formation. The electrical power supply is configured to provide a relatively constant amount of time-varying electrical current that remains within about 15% of a selected constant current value when a load of the electrical conductors changes.

Abstract: The invention provides a system configured to heat at least a part of a subsurface formation. The system includes: an electrical power supply configured to provide modulated direct current (DC); and one or more electrical conductors configured to be electrically coupled to the electrical power supply and placed in an opening in the formation, wherein at least one of the electrical conductors has a heater section, the heater section comprising an electrically resistive ferromagnetic material configured to provide an electrically resistive heat output when electrical current is applied to the ferromagnetic material, and the heater section is configured to provide a reduced amount of heat near or above a selected temperature during use due to the decreasing electrical resistance of the heater section when the temperature of the ferromagnetic material is near or above the selected temperature, and the heater section has a turndown ratio of at least 1.1 to 1.

Abstract: A method for resistively heating a subterranean region to lower the viscosity of heavy oil by using production tubing coupled to at least two electrodes modified for three-phase flow and an electrically insulating body.

Abstract: In an embodiment, a system may be used to heat a hydrocarbon containing formation. The system may include a conduit placed within an opening in the formation. A conductor may be placed within the conduit. The conductor may provide heat to a portion of the formation. In some embodiments, an electrically conductive material may be coupled to a portion of the conductor in the overburden. The electrically conductive material may lower the electrical resistance of the portion of the conductor in the overburden. Lowering the electrical resistance of the portion of the conductor in the overburden may reduce the heat output of the portion in the overburden. The system may allow heat to transfer from the conductor to a section of the formation.

Abstract: A heater may include an electrical conductor. Applying alternating current to the electrical conductor may generate resistively heat the electrical conductor. The electrical conductor may include an electrically resistive ferromagnetic material. The ferromagnetic material may at least partially surround a non-ferromagnetic material. The heater may provide a reduced amount of heat above or near a selected temperature. A conduit may at least partially surround the electrical conductor. A centralizer may maintain a separation distance between the electrical conductor and the conduit.

Abstract: An electrode assembly comprising concentric tubular electrodes is provided for high temperature processing of materials. The electrode assembly is connected with a power supply that includes switching means for alternatively operating the electrode assembly in a transferred mode of operation, in a non-transferred mode of operation, or according to a controlled sequence of non-transferred and transferred modes of operation. The power supply system includes variable inductors, such as leakage-coupled reactors, for controlling the electrical power supplied to the electrodes for producing a DC arc. The electrode assembly can be incorporated into an arc furnace for processing waste material in the furnace. The electrode assembly is also suitable for use in the practice of in-situ vitrification and remediation of contaminated soil.

Abstract: A method and apparatus for radon mitigation using convection versus a fan to exhaust soiled radon contaminated air from beneath a building or dwellings foundation slab. Two suitable orifices one at each end of a dwellings foundations slab are created. On top of one orifice, a section of pipe with a heating element inside is placed. This is coupled with additional sections of pipe and routed vertically thru the dwellings roof. The heating element creates convection, which draws the air beneath the slab up exiting the dwelling at the roof. At the opposite end orifice a fresh air inlet pipe is placed drawing air from outside of dwelling. A suitable layer of gas permeable material is required under the slab for fresh air to flow. One major advantage of the heating element opposed to a fan is its indefinite life span.

Abstract: A hydrocarbon containing 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 from heat sources to raise a temperature of a portion of the formation to a desired temperature. Some of the heat sources may be conductors placed within conduits. The conductors may be resistively heated so that the conductors radiantly heat the conduits. The conduits may transfer heat to the formation.

Abstract: Systems and methods are described for heating a subsurface formation. Alternating electrical current may be applied to one or more electrical conductors. The electrical conductors may be located in a subsurface formation. The electrical conductors may provide an electrically resistive heat output upon application of the alternating electrical current. At least one of the electrical conductors may include an electrically resistive ferromagnetic material. The electrical conductor may provide a reduced amount of heat above or near a selected temperature. Heat may be allowed to transfer from the electrical conductor to a part of the subsurface formation.

Abstract: A hydrocarbon containing 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 from heat sources to raise a temperature of a portion of the formation to a desired temperature. A heat transfer fluid may be circulated within wellbores of some heat sources to heat the formation. The heat transfer fluid may be combustion gas from burners.

Abstract: A wet electric heating (“WEH”) process involves establishing electrode zones (“e-zones”) around conductors (e.g., wells) for distributing electric current and thereby generating and distributing heat accordingly through a target region in a subterranean formation having hydrocarbons. The inventive WEH process takes into account e-zone geometric shape, spacing and/or spatial orientation to provide a more diffuse distribution of increased temperature values within the target region, compared to conventional electric heating processes, during at least the first 10% of a time interval when an electric potential is applied.

Abstract: An oil shale formation may be treated using an in situ thermal process. A mixture of 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 desited temperature. A heating rate for a selected volume of the formation may be controlled by altering an amount of heating energy per day that is provided to the selected volume.

Abstract: A hydrocarbon containing formation may be treated using an in situ thermal process. A mixture of 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. After pyrolysis, the portion may be heated to a synthesis gas production temperature. A synthesis gas producing fluid may be introduced into the portion to generate synthesis gas. Synthesis gas may be produced from the formation in a batch manner or in a substantially continuous manner.

Abstract: A coal formation may be treated using an in situ thermal process. A mixture of 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. A high hydrogen partial pressure within the formation may allow for hydrogenation of formation fluid within the formation. In addition, hydrogen, from produced formation fluid or from another source, may be used to hydrogenate produced fluid in a surface hydrogenation unit. The mixture produced from the formation may have a relatively high hydrogen partial pressure, and a large portion of the pressure within the formation may be attributable to hydrogen partial pressure.

Abstract: An electrode assembly comprising concentric tubular electrodes is provided for high temperature processing of materials. The electrode assembly is connected with a power supply that includes switching means for alternatively operating the electrode assembly in a transferred mode of operation, in a non-transferred mode of operation, or according to a controlled sequence of non-transferred and transferred modes of operation. The power supply system includes variable inductors, such as leakage-coupled reactors, for controlling the electrical power supplied to the electrodes for producing a DC arc. The electrode assembly can be incorporated into an arc furnace for processing waste material in the furnace. The electrode assembly is also suitable for use in the practice of in-situ vitrification and remediation of contaminated soil.

Abstract: A hydrocarbon containing formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. The produced mixture may include a hydrocarbon component. The hydrocarbon component may include a relatively low weight percentage of compounds having carbon numbers greater than 25. The hydrocarbon component may include oxygenated hydrocarbon compounds and a relatively low amount of olefins.

Abstract: A hydrocarbon containing formation may be treated using an in situ thermal process. A mixture of 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. The mixture produced from the formation may contain condensable hydrocarbons, with some of the hydrocarbons being oxygen containing hydrocarbons.

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 coal formation may be treated using an in situ thermal process. A mixture of 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. The formation to be treated may be selected based on initial moisture content of the formation.

Abstract: A power cable for an ESP is used also for heating well bores in cold climates. An electrical switch is located within a wellbore at a selected location in the power cable. The electrical switch is provided to selectively short out the conductors within the power cable, thereby allowing the power cable above the switch to be used as a resistive heating element to thaw the wellbore. While the switch is open, power supplied to power cable drives ESP in a normal manner.