JP5938347B2 - Press-fit connection joint for joining insulated conductors - Google Patents

Description

  The present invention relates to a system for insulated conductors used in heater elements. More particularly, the present invention relates to a fixture for connecting insulated conductor cables.

  Hydrocarbons obtained from underground formations are widely used as energy resources, raw materials, and consumer products. Processes for more efficient recovery, treatment, and / or use of available hydrocarbon resources are concerns about the depletion of available hydrocarbon resources as well as concerns about the overall quality degradation of the produced hydrocarbons. Has led to the development of. Use an in situ process to remove hydrocarbon material from underground formations that were previously inaccessible and / or too expensive to remove using available methods be able to. To improve the chemical and / or physical properties of the hydrocarbon material in the underground formation so that the hydrocarbon material can be more easily removed from the underground formation and / or to increase the value of the hydrocarbon material. May need to change. Chemical and physical changes generate hydrocarbons in the formation that can be removed and cause changes in composition, changes in solubility, changes in density, phase changes, and / or changes in viscosity. Reaction may be included.

  A heater can be placed in the wellbore to heat the formation in the field process. There are many different types of heaters that can be used to heat the formation. Examples of in-situ processes using heaters in downholes are Ljungstrom U.S. Pat. No. 2,634,961, Ljungstrom U.S. Pat. No. 2,732,195, Ljungstrom U.S. Pat. No. 2,780. , 450, Ljungstrom US Pat. No. 2,789,805, Ljungstrom US Pat. No. 2,923,535, Van Meurs et al. US Pat. No. 4,886,118, And Wellington et al., US Pat. No. 6,688,387.

US Pat. No. 2,634,961 US Pat. No. 2,732,195 US Pat. No. 2,780,450 US Pat. No. 2,789,805 US Pat. No. 2,923,535 US Pat. No. 4,886,118 US Pat. No. 6,688,387

  Inorganic insulated (MI) cables (insulated conductors) used for underground applications, such as heating formations containing hydrocarbons in some applications, are longer and more typical than typical in the MI cable industry. It can have a large outer diameter and can operate at higher voltages and temperatures. Numerous problems can be considered in the manufacture and / or assembly of long insulated conductors.

  For example, there may be electrical and / or mechanical problems due to aging of electrical insulators used for insulated conductors. There can also be problems with the electrical insulators to be overcome when assembling the insulated conductor heater. Problems such as core bulge or other mechanical defects may occur during assembly of the insulated conductor heater. Such an event can lead to electrical problems when using the heater and can result in the heater failing to serve its intended purpose.

  Furthermore, in underground applications, to create a sufficiently long MI cable to reach the depth and distance required to efficiently heat the underground, and to join sites with different functions (e.g., In order to connect the lead-in cable to the heater portion), it may be necessary to connect multiple MI cables together. Such long heaters also require higher voltages to provide sufficient power to the farthest end of the heater.

  Conventional MI cable splice designs are typically not suitable for voltages greater than 1000V, greater than 1500V, or greater than 2000V, greater than 650 ° C (approximately 1200 ° F), and 700 ° C It cannot operate over a long period of time without causing problems at high temperatures above (about 1290 ° F.) or above 800 ° C. (about 1470 ° F.). Such high voltage and high temperature applications typically require that the compression of the inorganic insulator in the splice is as close as possible to or greater than the level of compression in the insulated conductor (MI cable) itself.

  In some applications, due to the relatively large outer diameter and long length of MI cables, it is necessary to tie the cables together in a horizontally oriented state. There are splices for other uses of MI cables that are made horizontally. These techniques typically use small holes to fill an inorganic insulator (such as magnesium oxide powder) into the splice and compress it slightly by vibration and tamping. Such a method does not result in sufficient compression of the inorganic insulator, and in some cases, compression of the inorganic insulator is not possible at all, thus making a splice used at the high voltages required for the above-mentioned underground applications. Not suitable for.

  Therefore, a need exists for an insulated conductor splice that can function at high voltages and temperatures in a subterranean environment for a long period of time without being inconvenienced. Furthermore, splices may require higher bending and tensile strengths so that they do not fail under the heavy loads and temperatures that can be applied to cables underground. In addition, techniques and methods for reducing the electric field strength at the splice so as to reduce leakage current at the splice and increasing the margin between operating voltage and electrical breakdown can also be utilized. Lowering the charge intensity can also help to increase the operating range of the splice voltage and temperature.

  Furthermore, there can be problems due to large stresses on the insulated conductor during assembly of the insulated conductor and / or underground installation. For example, wrapping an insulated conductor around a spool used to transport and install the insulated conductor and even pulling it out of the spool can lead to mechanical stress on the electrical insulation and / or other components of the insulated conductor There is. Therefore, there is a need for a more reliable system and method for reducing or eliminating problems that may arise during the manufacture, assembly, and / or installation of insulated conductors.

  Embodiments described herein generally relate to systems, methods, and heaters for processing underground formations. Furthermore, the embodiments described herein generally relate to heaters having novel components. Such a heater can be obtained by using the systems and methods described herein.

  In certain embodiments, the present invention provides one or more systems, methods, and / or heaters. In some embodiments, the systems, methods, and / or heaters are used to process underground formations.

  In certain embodiments, a fixture for connecting the end of the first insulated conductor to the end of the second insulated conductor includes the end of the first insulated conductor and the end of the second insulated conductor. A sleeve configured to be disposed on the outside of the portion, and located inside the sleeve so as to fit around an end of the core of the first insulated conductor and an end of the core of the second insulated conductor A core joint configured, wherein the inner space of the sleeve is configured to be at least partially filled with an electrically insulating material, the electrically insulating material being coupled to the insulated conductor It is comprised so that it may be compressed by the edge part of the electrical insulator of a 1st insulated conductor, and the edge part of the electrical insulator of a 2nd insulated conductor.

  In further embodiments, features from individual embodiments can be combined with features from other embodiments. For example, features from one embodiment can be combined with features from any remaining embodiment.

  In further embodiments, the processing of the underground formation is performed using any of the methods, systems, power supplies, or heaters described herein.

  In further embodiments, additional features can be added to the individual embodiments described herein.

  The features and advantages of the method and apparatus of the present invention will be more fully understood by reference to the following detailed description of the presently preferred embodiments of the invention, but only by way of example, in conjunction with the accompanying drawings. Will be understood.

FIG. 2 shows a schematic diagram of an embodiment of a portion of an in situ heat treatment system for treating a formation containing hydrocarbons. 2 illustrates an embodiment of an insulated conductor heat source. 2 illustrates an embodiment of an insulated conductor heat source. 2 illustrates an embodiment of an insulated conductor heat source. FIG. 6 shows a cross-sectional view of the fixture when the insulated conductor is moved to the fixture. Sectional drawing of the fixture of the state in which the insulated conductor was joined inside the fixture is shown.

  While the invention is susceptible to various modifications and alternative forms, certain specific embodiments thereof are shown by way of example in the drawings and will be described in detail herein. The drawings are not necessarily to scale. The drawings and detailed description are not intended to limit the invention to the particular form disclosed, but rather are encompassed by the spirit and scope of the invention as defined by the appended claims. It should be understood to include all modifications, equivalents, and alternatives made.

  The following description relates generally to systems and methods for treating hydrocarbons in formations. Such formations can be treated to yield hydrocarbon products, hydrogen, and other products.

  “Alternating current (AC)” refers to a time-varying current that reverses direction in a substantially sinusoidal fashion. AC causes a skin effect of current in a ferromagnetic conductor.

  “Connection” means a direct or indirect connection (eg, one or more intervening connections) between one or more objects or components. The expression “directly connected” means a direct connection between objects or components such that the objects or components are directly connected to each other so that they work in a “point of use” manner. .

  “Geological formation” includes one or more hydrocarbon-containing layers, one or more non-hydrocarbon layers, overburden, and / or underburden. “Hydrocarbon layer” refers to a layer containing hydrocarbons in the formation. The hydrocarbon layer can include non-hydrocarbon materials and hydrocarbon materials. “Upper soil” and / or “lower soil” includes one or more different types of impermeable materials. For example, the upper soil and / or the lower soil can include bedrock, shale, mudstone, or wet / consolidated carbonate. In some embodiments of the in situ heat treatment process, the upper soil and / or lower soil is one or more hydrocarbon-containing layers that are relatively impervious, wherein the upper soil and / or the lower soil One or more hydrocarbon-containing layers can be included that are not exposed to temperatures during in situ heat treatment processes that lead to significant property changes of the soil hydrocarbon-containing layer. For example, the subsoil can include shale or mudstone, but is not heated to the pyrolysis temperature during the in situ heat treatment process. In some cases, the upper soil and / or the lower soil may be permeable to some extent.

  “Geological fluid” refers to fluid present in the formation and can include pyrolysis fluid, synthesis gas, mobilized hydrocarbons, and water (steam). The formation fluid can include hydrocarbon fluids and non-hydrocarbon fluids. The term “mobilizing fluid” refers to a fluid that has become flowable as a result of heat treatment of the formation in a formation containing hydrocarbons. “Production fluid” refers to fluid removed from the formation.

  A “heat source” is any system for supplying heat to at least a portion of the formation through substantially conductive and / or radiative heat transfer. For example, the heat source can include an electrically conductive material and / or can comprise an electrical heater such as an insulated conductor, an elongated member, and / or a conductor disposed within a conduit. The heat source may comprise a system that generates heat by burning fuel outside or inside the formation. The system may be a surface burner, a downhole gas burner, a flameless distributed combustor, and a natural distributed combustor. In some embodiments, heat supplied to one or more heat sources or generated in one or more heat sources can be provided by other energy sources. Other energy sources can heat the formation directly, or energy can be applied to a transmission medium that heats the formation directly or indirectly. It should be understood that one or more heat sources that apply heat to the formation may use different energy sources. That is, for example, for a given formation, some heat sources can supply heat from conductive materials or electrical resistance heaters, some heat sources can provide heat from combustion, The heat source can provide heat from one or more other energy sources (eg, chemical reaction, solar energy, wind energy, biomass, or other renewable energy sources). The chemical reaction can include an exothermic reaction (eg, an oxidation reaction). The heat source may also comprise a conductive material and / or a heater that provides heat to and / or around the heating location, such as a heater well.

  A “heater” is any system or heat source for generating heat in the vicinity of a well or area of a wellbore. The heater may be, but is not limited to, an electric heater, a burner, a combustor that reacts with material in the formation or material generated from the formation, and / or combinations thereof.

  “Hydrocarbon” is generally defined as a molecule formed primarily by carbon and hydrogen atoms. Hydrocarbons may include other elements such as, but not limited to, halogens, metal elements, nitrogen, oxygen, and / or sulfur. The hydrocarbon may be, but is not limited to, kerogen, bitumen, pyrobitumen, oil, natural mineral wax, and asphaltite. The hydrocarbon can be located within the Earth's mineral matrix or can be located adjacent to the Earth's mineral matrix. Substrates can include, but are not limited to, sedimentary rock, sand, silicilite, carbonate, diatomite, and other porous media. A “hydrocarbon fluid” is a fluid containing hydrocarbons. Hydrocarbon fluids can include, can include, or can include non-hydrocarbon fluids such as hydrogen, nitrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, water, and ammonia. It may be taken in.

  An “in situ conversion process” heats a formation containing hydrocarbons from a heat source and raises the temperature of at least a portion of the formation to a temperature above the pyrolysis temperature so that pyrolysis fluid is generated in the formation. Refers to the process

  “In-situ heat treatment process” involves heating a formation containing hydrocarbons with a heat source so that mobilized fluid, viscosity reducing fluid, and / or pyrolysis fluid is generated in the formation, Refers to the process of raising the temperature of at least a portion of the formation to a temperature above that which results in viscosity reduction and / or thermal decomposition of the hydrocarbon-containing material.

  "Insulated conductor" refers to any elongated material that can conduct electricity and is wholly or partially covered by an electrically insulating material.

  “Nitride” refers to a compound of nitrogen and one or more other elements of the periodic table. Nitrides include, but are not limited to, silicon nitride, boron nitride, or alumina nitride.

  A “perforation” is located in the wall of a conduit, tube, pipe, or other flow path and enters or enters the conduit, tube, pipe, or other flow path Includes openings, slits, holes, or holes that allow outflow.

  “Pyrolysis” is the breaking of chemical bonds resulting from the application of heat. For example, pyrolysis includes converting a compound into one or more other substances only by heat. Heat can be transferred to a portion of the formation to cause pyrolysis.

  “Pyrolysis fluid” or “pyrolysis product” refers to a fluid that is substantially produced during the pyrolysis of hydrocarbons. The fluid generated by the pyrolysis reaction may be mixed with other fluids in the formation. The mixture is considered a pyrolysis fluid or pyrolysis product. As used herein, a “pyrolysis zone” is a portion of a formation that is reacted or reacts to form a pyrolysis fluid (eg, a relatively permeable formation such as a tar sand formation). Point to.

  The “thickness” of a layer refers to the thickness of the cross section of the layer, the cross section being perpendicular to the plane of the layer.

  The term “wellhole” refers to a formation hole formed by excavation or insertion of a conduit into the formation. The well hole can have a substantially circular cross-section or other cross-sectional shape. As used herein, the terms “well” and “opening” can be used interchangeably with the term “wellhole” when referring to formation openings.

  The formation can be processed in a variety of ways to produce a number of different products. Various stages or processes can be used to treat the formation during the in situ heat treatment process. In some embodiments, one or more sites of the formation are melt mined to remove soluble minerals from the sites. Mineral melt mining can be performed before, during, and / or after the in situ heat treatment process. In some embodiments, the average temperature of one or more sites being melt mined can be maintained below about 120 ° C.

  In some embodiments, one or more sites of the formation are heated to remove water from the sites and / or to remove methane and other volatile hydrocarbons from the sites. In some embodiments, in removing water and volatile hydrocarbons, the average temperature can be raised from ambient temperatures to temperatures below about 220 ° C.

  In some embodiments, one or more portions of the formation are heated to a temperature that allows hydrocarbon migration and / or viscosity reduction within the formation. In some embodiments, the average temperature of one or more sites of the formation is the hydrocarbon mobilization temperature of the site (eg, in the range of 100 ° C. to 250 ° C., in the range of 120 ° C. to 240 ° C., or Temperature in the range of 150 ° C to 230 ° C).

  In some embodiments, one or more sites are heated to a temperature that allows a pyrolysis reaction in the formation. In some embodiments, the average temperature of one or more sites of the formation is determined by the hydrocarbon pyrolysis temperature (eg, in the range of 230 ° C to 900 ° C, in the range of 240 ° C to 400 ° C, or 250 The temperature can be raised to a temperature in the range of from ° C to 350 ° C.

  By heating a formation containing hydrocarbons with multiple heat sources, it is possible to establish a temperature gradient around the heat source that raises the temperature of the hydrocarbons in the formation to the desired temperature at the desired heating rate It is. For the desired product, manipulate the quality and quantity of formation fluids generated from hydrocarbon-containing formations by the rate of temperature rise through the mobilization temperature range and / or the pyrolysis temperature range It is possible. Slowly raising the formation temperature through the mobilization temperature range and / or pyrolysis temperature range can enable the production of high quality, high API gravity hydrocarbons from the formation. Slowly raising the formation temperature through the mobilization temperature range and / or pyrolysis temperature range to allow removal of large quantities of hydrocarbons present in the formation as hydrocarbon products it can.

  In some in situ heat treatment embodiments, a portion of the formation is heated to the desired temperature instead of slowly heating the temperature through the temperature range. In some embodiments, the desired temperature is 300 ° C, 325 ° C, or 350 ° C. Other temperatures may be selected as the desired temperature.

  Superposition of heat from the heat source allows the desired temperature in the formation to be established relatively quickly and efficiently. The input of energy from the heat source to the formation can be adjusted to maintain the formation temperature substantially at the desired temperature.

  The products of mobilization and / or pyrolysis can be produced from the formation by production wells. In some embodiments, the average temperature of one or more sites is increased to the mobilization temperature and hydrocarbons are produced from the production well. The average temperature of one or more sites can be raised to the pyrolysis temperature after production by mobilization falls below a predetermined value. In some embodiments, the average temperature of one or more sites can be raised to the pyrolysis temperature with little production before reaching the pyrolysis temperature. A formation fluid containing pyrolysis products may be generated through the production well.

  In some embodiments, the average temperature of one or more sites can be increased to a temperature sufficient to allow synthesis gas generation after mobilization and / or pyrolysis. In some embodiments, the hydrocarbons are brought to a temperature sufficient to allow synthesis gas to be produced, and there is little production before reaching a temperature sufficient to allow synthesis gas production. Can be raised. For example, synthesis gas can be generated at a temperature range of about 400 ° C to about 1200 ° C, about 500 ° C to about 1100 ° C, or about 550 ° C to about 1000 ° C. A syngas generating fluid (eg, steam and / or water) can be introduced into the site for generating syngas. Syngas can be produced from the production well.

  Dissolved mining, removal of volatile hydrocarbons and water, hydrocarbon mobilization, hydrocarbon pyrolysis, synthesis gas generation, and / or other processes can be performed in an in situ heat treatment process. In some embodiments, some processes can be performed after the in situ heat treatment process. Such processes include, but are not limited to, recovering heat from the treated site, storing fluid (eg, water and / or hydrocarbons) in the previously treated site, and / or Or it can be mentioned to sequester carbon dioxide in a pre-treated part.

  FIG. 1 shows a schematic diagram of an embodiment of a portion of an in situ heat treatment system for treating a formation containing hydrocarbons. The in situ heat treatment system can include a barrier well 200. The barrier well 200 is used to form a barrier around the processing area. The barrier suppresses the inflow of fluid into the processing region and / or the outflow of fluid from the processing region. Barrier wells include, but are not limited to, dewatering wells, vacuum wells, capture wells, injection wells, grout wells, frozen wells, or combinations thereof. In some embodiments, the barrier well 200 is a dewatering well. The dewatering well can remove the liquid water and / or can prevent the liquid water from entering the heating target region of the formation or the formation being heated. In the embodiment shown in FIG. 1, the barrier well 200 is shown extending only along one side of the heat source 202, but the barrier well is typically a formation treatment area. Encloses all the heat sources 202 used or to be used.

  The heat source 202 is disposed in at least a portion of the formation. The heat source 202 may comprise a heater such as an insulated conductor, a conduit conductor heater, a surface burner, a flameless distributed combustor, and / or a naturally distributed combustor. The heat source 202 may include other types of heaters. The heat source 202 provides heat to at least a portion of the formation to heat the hydrocarbons within the formation. Energy can be supplied to the heat source 202 via the supply line 204. The supply line 204 may be structurally different depending on the type of one or more heat sources used to heat the formation. Supply line 204 for the heat source can carry electricity for the electric heater, can carry fuel for the combustor, or can carry heat exchange fluid that circulates through the formation. In some embodiments, electricity for the in situ heat treatment process may be provided by one or more nuclear power plants. The use of nuclear power can reduce or eliminate carbon dioxide emissions from on-site heat treatment processes.

  When the formation is heated, the input of heat to the formation can cause the formation to expand and geotechnical movement. The heat source can be activated prior to, simultaneously with, or during the dehydration process. Computer simulations can be used to model the formation's response to heating. Computer simulations show patterns and time sequences for operating heat sources in the formation so that the geotechnical movement of the formation does not adversely affect the function of the heat source, production wells, and other equipment in the formation. Can be used to develop.

  Heating the formation can cause an increase in formation permeability and / or porosity. An increase in permeability and / or porosity can result from a reduction in formation mass due to water evaporation and removal, hydrocarbon removal, and / or crushing. The fluid can flow more easily through heated portions of the formation due to increased permeability and / or porosity of the formation. The fluid in the heated area of the formation can travel a considerable distance through the formation due to increased permeability and / or porosity. The substantial distance can exceed 1000 meters depending on various factors such as formation permeability, fluid properties, formation temperature, and pressure gradients that allow fluid movement. The ability for fluid to travel a significant distance within the formation allows production wells 206 to be relatively spaced apart in the formation.

  Production well 206 is used to remove formation fluid from the formation. In some embodiments, the production well 106 comprises a heat source. The production well heat source can heat one or more portions of the formation in or near the production well. In some field heat treatment process embodiments, the amount of heat per meter of production well supplied from the production well to the formation is greater than the amount of heat per meter of heat source applied from the heat source heating the formation to the formation. Is also small. Heat applied to the formation from the production well evaporates and removes the liquid phase fluid adjacent to the production well and / or penetrates the formation adjacent to the production well by forming macro and / or micro fracturing. By increasing the permeability, it is possible to increase the permeability of the formation adjacent to the production well.

  Two or more heat sources may be placed in the production well. Turn off the heat source at the site below the production well if the superposition of heat from adjacent heat sources sufficiently heats the formation to negate the benefits provided by heating the formation in the production well. can do. In some embodiments, after the heat source at the site below the production well is turned off, the heat source at the site above the production well may remain on. A heat source at a location above the production well can suppress the condensation and return of the formation fluid.

  In some embodiments, the heat source of the production well 206 allows gas phase removal of formation fluid from the formation. By providing heating in the production well or through the production well, the following is possible. That is, (1) when such product fluid moves in a production well adjacent to the upper soil, condensation and / or reflux of the product fluid can be suppressed, and (2) heat input to the formation is increased. (3) The production rate from the production well can be increased compared to a production well without a heat source. (4) Condensation of high carbon number compounds (C6 or higher hydrocarbons) in the production well And / or (5) the permeability of the formation in the vicinity of the production well or the production well can be increased.

  The underground pressure in the formation can correspond to the pressure of the fluid generated in the formation. As the temperature of the area to be heated in the formation increases, the pressure at the area to be heated can increase as a result of thermal expansion of the in-situ fluid, increased fluid generation, and water evaporation. By controlling the rate of fluid removal from the formation, the pressure in the formation can be controlled. The pressure in the formation can be determined at several different locations, such as near a production well or production well, near a heat source or heat source, or a monitoring well.

  In some formations containing hydrocarbons, production of hydrocarbons from the formation is suppressed until at least some of the hydrocarbons in the formation are mobilized and / or pyrolyzed. . If the formation fluid has a selected quality, it is possible to produce the formation fluid from the formation. In some embodiments, the selected quality includes an API gravity of at least about 20 °, 30 °, or 40 °. Suppressing production until at least some of the hydrocarbons are mobilized and / or pyrolyzed can increase the conversion of heavy hydrocarbons to light hydrocarbons. Suppressing initial production can minimize the production of heavy hydrocarbons from the formation. The production of substantial amounts of heavy hydrocarbons requires expensive equipment and / or can shorten the life of the production equipment.

  In some formations containing hydrocarbons, the hydrocarbons in the formation are heated to the mobilization temperature and / or pyrolysis temperature before substantial permeability occurs at the heated site of the formation. Is possible. Since there is no permeability at the beginning, the movement of the generated fluid to the production well 206 can be suppressed. During initial heating, the pressure of the fluid in the formation can be increased near the heat source 202. The increased fluid pressure can be released, monitored, changed, and / or controlled by one or more heat sources 202. For example, the selected heat source 202 or a separate pressure relief well can include a pressure relief valve that allows for removal of some fluid from the formation.

  In some embodiments, an open path to the production well 206 or any other pressure sink may not yet exist in the formation, but the mobilized fluid, pyrolysis fluid generated in the formation Or the pressure caused by the expansion of other fluids may be able to increase. It may be possible for the pressure of the fluid to increase towards the ground pressure. When the fluid reaches ground pressure, the formation of hydrocarbon-containing formations may occur. For example, fracturing can occur from the heat source 202 to the production well 206 at a heated site in the formation. Generation | occurrence | production of the crushing in the heated site | part can release a part of pressure of the said site | part. The pressure in the formation must be kept below a certain pressure to suppress undesirable production, to suppress the crushing of the upper or lower soil, and / or to suppress the coking of hydrocarbons in the formation. It may be.

  After reaching the mobilization temperature and / or pyrolysis temperature and enabling production from the formation, the composition of the formation fluid produced is changed and / or controlled, compared to the non-condensable fluid in the formation fluid It is possible to change the pressure in the formation to control the proportion of condensable fluid at that time and / or to control the API gravity of the generated formation fluid. For example, more condensable fluid components can be generated by reducing the pressure. The condensable fluid component may contain a greater proportion of olefins.

  In some embodiments of the in-situ heat treatment process, the pressure in the formation can be kept high enough to promote the formation of formation fluids having API gravity greater than 20 °. By maintaining the pressure in the formation high, subsidence of the formation during on-site heat treatment can be suppressed. Maintaining high pressure can reduce or eliminate the need for compression at the surface of the earth to carry formation fluids to the treatment facility in the recovery conduit.

  By maintaining a high pressure in the heated area of the formation, surprisingly large quantities of improved quality and relatively low molecular weight hydrocarbons can be produced. The pressure can be maintained so that the amount of compound above a given carbon number is minimized in the generated formation fluid. The predetermined number of carbons may be up to 25, up to 20, up to 12, or up to 8. Some high carbon number compounds can be incorporated into the vapor in the formation and can be removed from the formation with the vapor. By maintaining a high pressure in the formation, it is possible to suppress the incorporation of a high carbon number compound and / or a polycyclic hydrocarbon compound into the vapor. High carbon number compounds and / or polycyclic hydrocarbon compounds can remain in the liquid phase within the formation for a significant amount of time. This considerable time can provide sufficient time for the compound to pyrolyze to form a low carbon number compound.

The production of relatively low molecular weight hydrocarbons is believed to be due in part to hydrogen self-production and reaction in a portion of the formation containing hydrocarbons. For example, by maintaining a high pressure, hydrogen generated in pyrolysis can be forced into the liquid phase in the formation. By heating a portion to a temperature within the pyrolysis temperature range, it is possible to pyrolyze hydrocarbons in the formation to produce a liquid phase pyrolysis fluid. The liquid phase pyrolysis fluid component produced can contain double bonds and / or radicals. Hydrogen (H ₂ ) in the liquid phase reduces the possibility of polymerization or formation of long chain compounds from the generated pyrolysis fluid by reducing the double bonds of the generated pyrolysis fluid. Is possible. Further, H ₂ can neutralize radicals in the generated pyrolysis fluid. The H ₂ in the liquid phase can inhibit the generated pyrolysis fluids from reacting with each other and / or reacting with other compounds in the formation.

  Formation fluid produced from the production well 206 can be conveyed to the treatment facility 210 via the collection tube 208. Formation fluids can also be produced from the heat source 202. For example, fluid can be produced from the heat source 202 to control the pressure in the formation adjacent to the heat source. The fluid produced from the heat source 202 can be conveyed to the collection tube 208 by tubing or piping, or the produced fluid can be conveyed directly to the processing facility 210 by tubing or piping. The processing facility 210 can include separation units, reaction units, quality enhancement units, fuel cells, turbines, storage vessels, and / or other systems and units for processing the produced formation fluid. The treatment facility can form transportation fuel from at least a portion of the hydrocarbons produced from the formation. In some embodiments, the transportation fuel may be a jet fuel such as JP-8.

  The insulated conductor can be used as an electric heater element or heat source for the heater. The insulated conductor can include an inner conductor (core) surrounded by an electrical insulator and an outer conductor (jacket). The electrical insulator can include an inorganic insulator (eg, magnesium oxide) or other electrical insulator.

  In certain embodiments, an insulated conductor is placed in an opening in the formation that contains hydrocarbons. In some embodiments, the insulated conductor is placed in an opening that does not have a formation casing containing hydrocarbons. By disposing the insulated conductor in the opening without the casing of the formation containing hydrocarbon, heat can be transferred from the insulated conductor to the formation by radiation and conduction. By using an opening that does not have a casing, it is possible to easily collect the insulated conductor from the well if necessary.

  In some embodiments, the insulated conductor can be placed in a casing in the formation, cemented in the formation, or filled into the opening with sand, gravel, or other filler material. The insulated conductor can be supported on a support member disposed in the opening. The support member may be a cable, rod, or conduit (eg, a pipe). The support member can be made of metal, ceramic, inorganic material, or a combination thereof. Because a portion of the support member can be exposed to formation fluids and heat during use, the support member can be chemically and / or thermally resistant.

  Ties, spot welds, and / or other types of connectors can be used to connect the insulated conductor to the support member at various locations along the length of the insulated conductor. The support member can be attached to the structure above the well in the upper surface of the formation. In some embodiments, the insulated conductor has sufficient structural strength such that a support member is not required. Insulated conductors can often have at least some flexibility to prevent damage due to thermal expansion when subjected to temperature changes.

  In certain embodiments, the insulated conductor is disposed in the wellbore without a support member and / or a centralizer. Insulated conductors without support members and / or centralizers have the appropriate combination of corrosion resistance, creep strength, length, thickness (diameter), and metallurgical technology to prevent failure of the insulated conductor in use be able to.

  FIG. 2 shows a perspective view of the end of an embodiment of the insulated conductor 212. Insulated conductor 212 has any desired cross-sectional shape including, but not limited to, circular (shown in FIG. 2), triangular, elliptical, rectangular, hexagonal, or irregularly shaped. Can do. In certain embodiments, the insulated conductor 212 includes a core 214, an electrical insulator 216, and a jacket 218. The core 214 can generate heat by resistance when current passes through the core. Alternating current or time-varying current and / or direct current can be used to provide power to the core 214 such that the core is heated by resistance.

  In some embodiments, the electrical insulator 216 prevents current leakage and arcing to the jacket 218. The electrical insulator 216 can conduct heat generated in the core 214 to the jacket 218. A jacket 218 can radiate or conduct heat to the formation. In certain embodiments, the length of the insulated conductor 212 is 1000 m or more. Longer or shorter insulated conductors can also be used to suit the needs of individual applications. The dimensions of the core 214, the electrical insulator 216, and the jacket 218 of the insulated conductor 212 can be selected so that the insulated conductor has sufficient strength to support itself even at the upper working temperature. Such an insulated conductor does not have to extend the support member together with the insulated conductor to a hydrocarbon-containing formation, but to the structure at the top of the well or the upper soil and the hydrocarbon-containing formation. Can be suspended from a support located near the boundary between the two.

  Insulated conductor 212 can be designed to operate at power levels up to about 1650 watts / meter or more. In certain embodiments, the insulated conductor 212 operates at a power level between about 500 watts / meter and about 1150 watts / meter when heating the formation. The insulated conductor 212 can be designed so that substantial thermal and / or electrical breakdown does not occur in the electrical insulator 216 even at the maximum voltage level at typical operating temperatures. The insulated conductor 212 can be designed so that the jacket 218 does not exceed a temperature that can lead to a significant decrease in the corrosion resistance of the jacket material. In certain embodiments, the insulated conductor 212 can be designed to reach a temperature in the range between about 650 ° C and about 900 ° C. Insulated conductors having other operating ranges can be formed to meet individual operating requirements.

  FIG. 2 shows an insulated conductor 212 having a single core 214. In some embodiments, the insulated conductor 212 has more than one core 214. For example, one insulated conductor can have three cores. The core 214 can be made of metal or other conductive material. Materials used to form the core 214 can include, but are not limited to, nichrome, copper, nickel, carbon steel, stainless steel, and combinations thereof. In certain embodiments, the core 214 is subject to a core resistance derived from Ohm's law, resulting in the power dissipation per meter, the heater length, and / or the maximum voltage allowed for the core material at which the core is selected. Is selected to have a diameter and resistivity at an operating temperature that is electrically and structurally stable.

  In some embodiments, the core 214 is made of a material that differs in the length of the insulated conductor 212. For example, the first portion of the core 214 can be made of a material that is significantly less resistant than the second portion of the core. The first site can be located adjacent to a formation that does not need to be heated to a higher temperature than the second formation adjacent to the second site. The resistivity of various parts of the core 214 can be adjusted by changing the diameter and / or can be adjusted by making the core part from different materials.

The electrical insulator 216 can be made of a variety of materials. Commonly used powders include, but are not limited to, MgO, Al ₂ O ₃ , zirconia, BeO, various chemical variants of spinel, and combinations thereof. MgO can provide good thermal conductivity and electrical insulation properties. Desired electrical insulation properties include low leakage current and high dielectric strength. A low leakage current reduces the possibility of thermal breakdown, and a high dielectric strength reduces the possibility of arcing across the insulator. Thermal breakdown can occur when the temperature of the insulator gradually increases due to leakage current, leading to arcing across the insulator.

  The jacket 218 may be an outer metal layer or a conductive layer. Jacket 218 may be in contact with hot formation fluids. The jacket 218 can be made of a material that has high corrosion resistance at high temperatures. Alloys that can be used in the desired operating temperature range of the jacket include, but are not limited to, 304 stainless steel, 310 stainless steel, Incoloy® 800, and Inconel® 600 (Inco Alloys). International, Huntington, West Virginia, USA). It is believed that the thickness of the jacket 218 must be sufficient to survive for 3-10 years in high temperature and corrosive environments. The thickness of the jacket 218 may generally vary between about 1 mm to about 2.5 mm. For example, a 1.3 mm thick 310 stainless steel outer layer can be used as the jacket 218 to provide good chemical resistance to sulfidation corrosion in the heating zone of the formation over a period of more than three years. Larger or smaller thicknesses of the jacket can be used to meet individual application requirements.

  One or more insulated conductors can be placed in the formation opening to form one or more heat sources. A current can be passed through each insulated conductor in the opening to heat the formation. Alternatively, current can be passed through selected insulated conductors in the opening. Unused conductors can be used as spare heaters. The insulated conductor can be electrically connected to the power source in any convenient manner. Each end of the insulated conductor can be connected to a lead-in cable that passes through the structure at the top of the well. Such a configuration typically has a 180 ° bend (“hairpin” curve) or turn located near the bottom of the heat source. Insulated conductors with 180 ° bends or turns can eliminate the need for termination at the bottom, but 180 ° bends or turns can be an electrical and / or structural weakness in the heater. Insulated conductors can be electrically connected to each other in series, in parallel, or in a combination of series and parallel. In some embodiments of the heat source, connecting the core 214 to the jacket 218 (shown in FIG. 2) at the bottom of the heat source allows current to pass to the conductor of the insulated conductor so that the jacket of the insulated conductor You can go back through.

  In some embodiments, three insulated conductors 212 are electrically connected to the power supply in a three phase Y configuration. FIG. 3 shows an embodiment of three insulated conductors connected in a Y configuration at the subsurface formation opening. FIG. 4 illustrates an embodiment of three insulated conductors 212 that can be removed from the formation opening 220. In the three insulated conductors having the Y-shape, the connection at the bottom can be made unnecessary. Alternatively, all three insulated conductors in a Y configuration may be connected to each other near the bottom of the opening. The connection can be made directly at the end of the heated portion of the insulated conductor or at the end of a low temperature pin (lower resistance site) connected to the heated portion at the bottom of the insulated conductor. The bottom connection may be made by a canister filled with insulation and sealed or a canister filled with epoxy. The insulator may have the same composition as the insulator used as electrical insulation.

The three insulated conductors 212 shown in FIGS. 3 and 4 can be connected to the support member 222 using a centralizer 224. Alternatively, the insulated conductor 212 may be secured directly to the support member 222 using a metal strap. The centralizer 224 can maintain the position of the insulated conductor 212 on the support member 222 and / or prevent movement. The centralizer 224 can be made of metal, ceramic, or a combination thereof. The metal may be stainless steel or any other type of metal that can withstand corrosive and high temperature environments. In some embodiments, the centralizer 224 is an arcuate piece of metal welded to the support member at a spacing of less than approximately 6 meters. The ceramic used for the centralizer 224 may be, but is not limited to, Al ₂ O ₃ , MgO, or other electrical insulator. The centralizer 224 can maintain the position of the insulated conductor 212 on the support member 222 so that the insulated conductor is prevented from moving at the operating temperature of the insulated conductor. Furthermore, the insulated conductor 212 may be somewhat flexible to withstand the expansion of the support member 222 during heating.

  Support member 222, insulated conductor 212, and centralizer 224 can be disposed in opening 220 of hydrocarbon layer 226. Insulated conductor 212 may be connected to bottom conductor joint 228 using low temperature pins 230. The bottom conductor joint 228 can electrically connect each insulated conductor 212 to each other. The bottom conductor joint 228 can include a conductive material that does not melt at the temperature found in the opening 220. The low temperature pin 230 may be an insulated conductor having an electrical resistance lower than that of the insulated conductor 212.

  The lead conductor 232 can be connected to the structure 234 at the top of the well for supplying power to the insulated conductor 212. The lead conductor 232 can be made of a conductor with a relatively low electrical resistance so that relatively little heat is generated due to the current passing through the lead conductor. In some embodiments, the lead-in conductor is a copper strand insulated with rubber or polymer. In some embodiments, the lead-in conductor is an inorganic insulated conductor having a copper core. The lead-in conductor 232 can be connected to the structure 234 at the top of the well located at the ground surface 236 via a sealing flange located between the upper soil 238 and the ground surface 236. The sealing flange can prevent fluid from escaping from the opening 220 to the ground surface 236.

  In certain embodiments, the lead conductor 232 is connected to the insulated conductor 212 using the tether conductor 240. The connecting conductor 240 may be a low resistance portion of the insulated conductor 212. The connecting conductor 240 can also be referred to as a “cold pin” of the insulated conductor 212. The tether conductor 240 can be designed so that the power dissipation per unit length is about 1/10 to about 1/5 compared to the main heated portion of the insulated conductor 212. The tether conductor 240 may typically be between about 1.5 m and about 15 m, although shorter or longer lengths may be used to meet the needs of individual applications. it can. In one embodiment, the conductor of the tie conductor 240 is copper. The electrical insulator of the connecting conductor 240 may be the same type as the electrical insulator used for the main heating portion. The jacket of the tether 240 can be made of a corrosion resistant material.

  In certain embodiments, the tether conductor 240 is connected to the lead conductor 232 by a splice or other connection joint. The splice can also be used to connect the tether conductor 240 to the insulated conductor 212. The splice may have to withstand a temperature equal to half the operating temperature of the zone of interest. The density of electrical insulation in the splice often has to be high enough to withstand the required temperature and operating voltage.

  In some embodiments, as shown in FIG. 3, a packing material 242 is disposed between the upper soil casing 244 and the opening 220. In some embodiments, the upper soil casing 244 may be secured to the upper soil 238 by the reinforcing material 246. The packing material 242 can prevent fluid from flowing from the opening 220 to the ground surface 236. Reinforcing material 246 can include, for example, silica powder, slag, or silica powder for improving high temperature performance, and / or Class G or Class H Portland cement mixed with mixtures thereof. In some embodiments, the reinforcing material 246 extends radially with a width of about 5 cm to about 25 cm.

  As shown in FIGS. 3 and 4, the support member 222 and the lead conductor 232 can be connected to a structure 234 at the top of the well located at the formation surface 236. A surface conductor 248 can surround the reinforcement material 246 and lead to the structure 234 at the top of the well. Some embodiments of surface conductors can extend to a depth of about 3 m to about 515 m into the formation opening. Alternatively, the surface conductor can extend to a depth of about 9 m into the formation. Current can be supplied from the power source to the insulated conductor 212 and heat can be generated by the electrical resistance of the insulated conductor. Heat generated from the three insulated conductors 212 can be transferred within the opening 220 to heat at least a portion of the hydrocarbon layer 226.

  Heat generated by the insulated conductor 212 can heat at least a portion of the formation containing hydrocarbons. In some embodiments, heat is transferred to the formation substantially by radiation of the generated heat to the formation. Some heat is transferred by heat conduction or convection by the gas present in the opening. As shown in FIGS. 3 and 4, the opening may be an opening without a casing. An opening without a casing eliminates the costs associated with thermally fixing the heater to the formation, the costs associated with the casing, and / or the cost of packing the heater into the opening. In addition, heat transfer by radiation is more efficient than heat transfer by conduction, so that heaters can be operated at lower temperatures in open well holes. Heat transfer by conduction during the initial operation of the heat source can be improved by adding gas to the opening. The gas can be maintained at a pressure of up to about 27 bar (absolute pressure). The gas can include, but is not limited to, carbon dioxide and / or helium. Insulated conductor heaters in open well holes are advantageously free to expand or contract to accommodate thermal expansion and contraction. The insulated conductor heater can be conveniently removed from the open wellbore or repositioned.

  In certain embodiments, the insulated conductor heater assembly is installed or removed using a spool assembly. More than one spool assembly can be used to install both the insulated conductor and the support member simultaneously. Alternatively, the support member can be installed using a wound tube unit. The heater can be withdrawn from the spool and connected to the support as it is inserted into the well. The electric heater and support member can be withdrawn from the spool assembly. The spacer can be connected to the support member and the heater at the length of the support member. Additional spool assemblies can be used for additional electric heater elements.

  Inorganic insulated (MI) cables (insulated conductors) used for underground applications, such as heating formations containing hydrocarbons in some applications, are longer and more typical than typical in the MI cable industry. It can have a large outer diameter and can operate at higher voltages and temperatures. In these underground applications, to create an MI cable long enough to reach the depth and distance needed to efficiently heat the underground, and to join sites with different functions (eg, pull-in) In order to connect the cable to the heater part), it is necessary to connect several MI cables together. Such long heaters also require higher voltages to provide sufficient power to the farthest end of the heater.

  Conventional MI cable splice designs are typically not suitable for voltages greater than 1000V, greater than 1500V, or greater than 2000V, greater than 650 ° C (approximately 1200 ° F), and 700 ° C It cannot operate over a long period of time without causing problems at high temperatures above (about 1290 ° F.) or above 800 ° C. (about 1470 ° F.). Such high voltage and high temperature applications typically require that the compression of the inorganic insulator in the splice is as close as possible to or greater than the level of compression in the insulated conductor (MI cable) itself.

  In some applications, due to the relatively large outer diameter and long length of MI cables, it is necessary to tie the cables together in a horizontally oriented state. There are splices for other uses of MI cables that are made horizontally. These techniques typically use small holes to fill an inorganic insulator (such as magnesium oxide powder) into the splice and compress it slightly by vibration and tamping. Such a method does not result in sufficient compression of the inorganic insulator, and in some cases, compression of the inorganic insulator is not possible at all, thus making a splice used at the high voltages required for the above-mentioned underground applications. Can not be suitable for.

  Therefore, a need exists for an insulated conductor splice that can function at high voltages and temperatures in a subterranean environment for a long period of time without being inconvenienced. Furthermore, splices may require higher bending and tensile strengths so that they do not fail under the heavy loads and temperatures that can be applied to cables underground. In addition, techniques and methods for reducing the field strength can be utilized to reduce leakage current in the splice and increase the margin between operating voltage and electrical breakdown. Lowering the charge intensity can also help to increase the operating range of the splice voltage and temperature.

  FIGS. 5 and 6 show cross-sectional views of another embodiment of a fixture 250 used to stitch together insulated conductors. FIG. 5 shows a cross-sectional view of the fixture 250 when the insulated conductors 212A, 212B are being moved into the fixture. FIG. 6 shows a cross-sectional view of the fixture 250 with the insulated conductors 212A, 212B joined together inside the fixture. In certain embodiments, the fixture 250 includes a sleeve 252 and a joint 258.

  To connect the fixture 250 to the insulated conductor 212A to the insulated conductor 212B while maintaining the mechanical and electrical integrity of the insulated conductor jacket (sheath), insulator, and core (conductor). Can be used for The fixture 250 can be used to connect an insulated conductor that generates heat to an insulated conductor that does not generate heat, and can be used to connect an insulated conductor that generates heat to an insulated conductor that generates another heat. Or an insulated conductor that does not generate heat can be used to connect another insulated conductor that does not generate heat. In some embodiments, two or more fixtures 250 are used to connect multiple insulated and non-heated insulated conductors to provide a long insulated conductor.

  The fixture 250 can be used to connect insulated conductors of different diameters. For example, the insulated conductors can have different core (conductor) diameters, different jacket (sheath) diameters, or combinations of different diameters. The fixture 250 can also be used to connect insulated conductors having different metallurgical techniques, different types of insulation, or combinations thereof.

  The joint 258 is used to connect and electrically connect the cores 214A and 214B of the insulated conductors 212A and 212B inside the fixture 250. The joint 258 can be made of copper or other suitable conductor. In certain embodiments, cores 214A, 214B are press fit or pushed into fittings 258. In some embodiments, the joint 258 is heated so that the cores 214A, 214B can be slid into the joint. In some embodiments, core 214A is made of a different material than core 214B. For example, core 214A may be copper while core 214B is stainless steel, carbon steel, or alloy 180. In such embodiments, special methods may have to be used to weld the cores together. For example, the core tensile strength characteristics and / or yield strength characteristics may have to be closely matched so that the connection between the cores does not degrade over time or use.

  In some embodiments, the joint 258 includes one or more grooves inside the joint. The grooves can prevent particles from entering and exiting the joint after the cores are stitched together in the joint. In some embodiments, the joint 258 has a tapered inner diameter (eg, the inner diameter decreases toward the center of the joint). The tapered inner diameter can provide better press fit between the joint 258 and the cores 214A, 214B.

  In certain embodiments, an electrically insulating material 256 is located inside the sleeve 252. In some embodiments, the electrically insulating material 256 is magnesium oxide or a mixture of magnesium oxide and boron nitride (80 wt% magnesium oxide and 20 wt% boron nitride). Examples of the electrical insulating material 256 include magnesium oxide, talc, ceramic powder (for example, boron nitride), a mixture of magnesium oxide and other electrical insulators (for example, up to about 50% by weight of boron nitride), ceramic cement, ceramic powder Mention may be made of mixtures with certain non-ceramic materials (such as tungsten sulfide (WS2)) or mixtures thereof. For example, magnesium oxide may be mixed with boron nitride or other electrical insulators to improve the fluidity of the electrical insulation material, improve the dielectric properties of the electrical insulation material, or improve the flexibility of the fixture. it can. In some embodiments, the electrically insulating material 256 is a material similar to the electrical insulator used within at least one of the insulated conductors 212A, 212B. The electrically insulating material 256 can have substantially the same dielectric properties as the electrical insulator used within at least one of the insulated conductors 212A, 212B.

  In certain embodiments, the space inside sleeve 252 is substantially filled with electrically insulating material 256. In certain embodiments, “substantially filled” completely or nearly completely fills the space (s) with an electrically insulating material such that there are substantially no macroscopic voids in the space (s). Refers to that. For example, “substantially filled” refers to filling substantially the entire space with an electrically insulating material having a certain degree of porosity (eg, up to about 40% porosity) due to microscopic voids.

  In some embodiments, the sleeve 252 has one or more grooves 308. The groove 308 can prevent the electrically insulating material 256 from moving out of the sleeve 252 (eg, the groove traps the electrically insulating material within the sleeve).

  In certain embodiments, the electrically insulating material 256 has a concave end at or near the edge of the joint 258 as shown in FIG. The concave shape of the electrically insulating material 256 can improve the coupling of the insulated conductors 212A, 212B with the electrical insulators 216A, 216B. In some embodiments, the electrical insulators 216A, 216B have convex (or tapered) ends to improve coupling with the electrical insulating material 256. The ends of the electrical insulating material 256 and the electrical insulators 216A, 216B can intermingle or mix under pressure applied when the insulated conductors are joined. Intermingling or mixing of insulating materials can improve the coupling between the insulated conductors.

  In certain embodiments, the insulated conductors 212A, 212B are joined at the fixture 250 by moving the insulated conductors toward the center of the fixture (pressing together). The cores 214A and 214B are joined inside the joint 258 as the insulated conductors 212A and 212B move. After the insulated conductors 212A and 21B move into the fixture 250, the insulated conductor is fixed to the fixture by compressing or pressing the ends of the fixture and the insulated conductor inside the fixture, and the electrical insulation is performed. The material 256 can be compressed. A clamp assembly or other similar device can be used to join the insulated conductors 212A, 212B and the fixture 250. In certain embodiments, the force to compress the electrically insulating material 256 is, for example, at least 25,000 pounds per square inch to up to 55,000 pounds per square inch to provide an acceptable compression of the insulating material. . The compression of the electrically insulating material 256 during the assembly process can provide the electrically insulating material with dielectric properties comparable to the dielectric properties of the electrically insulating material inside the insulated conductors 212A, 212B to a practical extent. Methods and devices for facilitating compression include, but are not limited to, mechanical methods, pneumatic, hydraulic / hydraulic, swage, or combinations thereof.

  In some embodiments, the end of the sleeve 252 is connected (welded or brazed) to the jackets 218A, 218B of the insulated conductors 212A, 212B. In some embodiments, a support sleeve and / or strain relief is placed over the fixture 250 to provide additional strength to the fixture.

  The fixture 250 shown in FIGS. 5 and 6 can form a robust electrical and mechanical connection between insulated conductors. For example, the fixtures shown herein may have a voltage of greater than 1000 volts, greater than 1500 volts, or greater than 2000 volts, and a temperature of at least about 650 ° C, at least about 700 ° C, or at least about 800 ° C Can be suitable to function.

  In certain embodiments, the fixtures shown herein are insulated conductors that are not used to heat insulated conductors that are used for heating (eg, insulated conductors that are disposed in hydrocarbon-containing layers) (eg, formations). To the insulated conductor used for the upper soil part). The heating insulated conductor can have a smaller core than the non-heating insulated conductor and a core of a material different from the non-heating insulated conductor. For example, the core of the insulated conductor for heating may be a copper-nickel alloy, stainless steel, or carbon steel, while the core of the insulated conductor that is not heated may be copper. However, due to differences in core size and material electrical properties, the electrical insulators at each location may have sufficiently different thicknesses that cannot be compensated for by joining the insulated conductors with a single fixture. . Thus, in some embodiments, a short intermediate heating insulated conductor can be used between a heated insulated conductor and a non-heated insulated conductor.

  The intermediate heating insulated conductor may have a core diameter that tapers from the diameter of the non-heating insulated conductor core to the diameter of the heating insulated conductor core, while the non-heating insulated conductor The same core material can be used. For example, the intermediate heating insulated conductor may be copper having a core diameter that tapers to the same diameter as the heating insulated conductor. In this way, the thickness of the electrical insulator in the fixture connecting the intermediate insulated conductor and the heated insulated conductor is the same as the thickness of the electrical insulator in the heated insulated conductor. By using the same thickness, the insulated conductor can be easily joined in the fixture. Intermediate heating insulated conductors can cause some voltage drop and some heating losses due to the small core diameter, while intermediate heating insulated conductors minimize these losses. It may be a relatively short length.

  It should be understood that the present invention is not limited to the specific systems described above, which can of course vary. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, “a core” includes a combination of two or more cores, and “a material” includes a mixture of materials.

  Further modifications and alternative embodiments for various aspects of the invention will be apparent to those skilled in the art in light of this specification. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It should be understood that the form of the invention shown and described herein is to be received as the presently preferred embodiment. While any would be apparent to one of ordinary skill in the art having the benefit of the foregoing description of the invention, alternative components and materials are possible for the components and materials illustrated and described herein, Parts and processes can be reversed, and certain features of the invention can be utilized independently. Changes may be made to the elements described herein without departing from the spirit and scope of the invention as described in the following claims.

Claims (14)

A fixture for connecting the end of the first insulated conductor to the end of the second insulated conductor,
A sleeve configured to be disposed over the end of the first insulated conductor and the end of the second insulated conductor;
Located inside the sleeve, it is configured to fit around the end of the first insulated conductor conductive core end and the second conductive core of the insulated conductor, the first and A conductive core joint for electrically connecting the core of the first insulated conductor to the core of the second insulated conductor when the end of the second insulated conductor is inserted into the fixture ;
When the internal space of the periphery of the core joint sleeve has been substantially filled with electrically insulating material, electrical insulating material, the ends of the first and second insulation conductor is inserted into the fixture, the A fixture configured to be compressed between an end of an electrical insulator of one insulated conductor and an end of the electrical insulator of a second insulated conductor. Each insulated conductor, a Ru the electrically insulating material is pressed into the said fitting being configured to compress the electrical insulation of the insulated conductor, fitting of claim 1. Core core and a second insulated conductor of the first insulated conductor, as attached pressed against each other in the core joint when the end of the first and second insulated conductor is moved into the fitting The fixture according to claim 1, which is configured as follows.   The fixture of claim 1, wherein the sleeve comprises one or more grooves for preventing movement of the electrically insulating material about to exit the sleeve.   The fixture of claim 1, wherein at least one of the insulated conductors comprises an electrical insulator that tapers at an angle from the jacket of the insulated conductor to the core of the insulated conductor within the fixture.   The fixture of claim 1, wherein the core joint has a tapered inner diameter with a smaller diameter in the center of the joint to improve contact of the insulated conductor with the core.   The fixture of claim 1, wherein the core joint includes one or more grooves located on the inner diameter of the joint to improve contact of the insulated conductor with the core.   The fixture of claim 1, wherein the electrically insulating material is configured to be compressed by a pressure of at least 25,000 pounds per square inch. Central fixture is configured to be positioned between the end of the end portion of the first insulated conductor second insulated conductors, fitting of claim 1.   The fixture according to claim 1, wherein the inner space of the fixture is configured to be reduced by application of water pressure / hydraulic pressure.   The fixture of claim 1, wherein the interior space of the fixture is configured to be reduced using a swage method. Electrically insulating material, it includes a substantially similar material as the electrical insulator at least one of the two insulated conductors, fitting of claim 1.   The fixture of claim 1, wherein at least one of the insulated conductors is configured to be used to heat an underground formation. The fitting of claim 1, wherein the core coupling is configured to fit tightly around the end of the core of the first insulated conductor and the end of the core of the second insulated conductor.

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