Shale oil in-situ exploitation horizontal well electric heating cable, electric heater, monitoring system and heating method

Abstract

The invention discloses a shale oil in-situ exploitation horizontal well electric heating cable, an electric heater, a monitoring system and a heating method.The electric heating cable comprises a cold section and a hot section which are sequentially connected, and the hot section is used for being arranged on a horizontal well section of a heating well; the cold section and the hot section of the electric heating cable respectively comprise a sheath layer, an insulating layer and a wire core from outside to inside; the sheath layer and the wire core are coaxially arranged, and the insulating layer is distributed between the sheath layer and the wire core; the sheath layer of the cold section is made of austenite alloy, and the sheath layer of the hot section is made of nickel-based alloy. According to the electric heating cable, the technical problem that a conventional heating cable cannot adapt to severe conditions and cannot work in a high-temperature, high-pressure and high-corrosion shale oil exploitation environment is solved, and the economical efficiency of the technology for exploiting shale oil is directly influenced by various factors such as materials, service life and heat energy consumption of the electric heating cable. And important test projects such as improvement of oil and gas resource strategy replacement and energy production and supply guarantee capability, promotion of shale oil in-situ conversion and the like are implemented.

Description

Technical Field

[0001] The present invention relates to the technical field of shale oil and gas in-situ mining, and in particular to an electric heating cable, an electric heater, a monitoring system and a heating method for a shale oil in-situ mining horizontal well. Background Art

[0002] The effective development of existing unconventional oil and gas is of great strategic significance for alleviating the pressure on oil and gas resource supply, ensuring energy security, and promoting low-carbon transformation of energy structure and green development. At present, low-grade resources represented by shale oil and gas have gradually become the main body of oil exploration and development in some regions. The application of downhole electric heater technology in new fields such as in-situ conversion of shale oil and gas is of great significance to improving the strategic succession of oil and gas resources and the ability to ensure energy production and supply, promoting the coordinated integration of fossil energy and new energy, and promoting the implementation of major experimental projects such as in-situ conversion of shale oil.

[0003] Electric heaters are the source of heat. The in-situ conversion process not only requires the installation, operation and maintenance of electric heaters to be convenient, but more importantly, the materials used for electric heaters must have properties such as high temperature resistance, corrosion resistance and good insulation. As an important part of shale in-situ conversion, heater technology has many factors such as material price, service life, and thermal energy consumption that directly affect the economic feasibility of shale oil extraction using this technology. Therefore, it is of great practical significance to develop a set of high-length, high-power, and long-life high-temperature downhole electric heating equipment. Summary of the invention

[0004] In order to solve the production needs of high-temperature, high-pressure, and highly corrosive shale oil production environments where conventional heaters cannot operate under such harsh working conditions, the present invention provides a shale oil in-situ production horizontal well electric heating cable, electric heater, monitoring system and heating method.

[0005] In a first aspect, an embodiment of the present invention provides an electric heating cable for horizontal wells for in-situ production of shale oil, wherein the electric heating cable may include: a cold section and a hot section connected in sequence, wherein the hot section is used to be arranged in a horizontal well section of a heating well; wherein the cold section and the hot section of the electric heating cable respectively include a sheath layer, an insulating layer and a core from the outside to the inside; the sheath layer and the core are coaxially arranged, and the insulating layer is distributed between the sheath layer and the core;

[0006] The material of the jacket layer of the cold section is an austenitic alloy, and the material of the jacket layer of the hot section is a nickel-based alloy.

[0007] In one embodiment, the base material of the wire core is a copper-nickel alloy, and the surface of the copper-nickel alloy is plated with cerium or palladium.

[0008] In another embodiment, the outer side of the wire core is wrapped with nickel foil or tin foil.

[0009] In another embodiment, the insulating layer is made of high-purity magnesium oxide and high-purity zirconium oxide; the mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer, and the mass fraction of the high-purity zirconium oxide is 0% to 50% of the insulating layer.

[0010] In another embodiment, the insulating layer is made of high-purity magnesium oxide and high-purity manganese oxide; the mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer, and the mass fraction of the high-purity manganese oxide is 0 to 50% of the insulating layer.

[0011] In another embodiment, the insulating layer is made of high-purity magnesium oxide, high-purity zirconium oxide and high-purity manganese oxide, the mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer, the mass fraction of the high-purity zirconium oxide is 0 to 50% of the insulating layer, and the mass fraction of the high-purity manganese oxide is 0 to 50% of the insulating layer.

[0012] In another embodiment, there are three wire cores in the electric heating cable, and the tail ends of the three wire cores are connected in a star shape to form tail end star-connected welding points.

[0013] In a second aspect, an embodiment of the present invention provides an electric heater for shale oil in-situ production horizontal wells, which may include: an electrical control cabinet, a guide, and an electric heating cable for shale oil in-situ production horizontal wells as described in the first aspect;

[0014] Among them, the electrical control cabinet is connected to the cold section of the electric heating cable to control the output voltage of the electric heating cable; the guide is connected to the hot section of the electric heating cable to guide the electric heating cable into the heating well through the casing.

[0015] In another embodiment, the electric heater may further include: two insulating sealing devices, one of the insulating sealing devices is sleeved on the end of the hot section and connected to the guide;

[0016] Another insulating sealing device is sleeved on the end of the cold section, and is connected to the cold section and the electrical control cabinet respectively through a power lead-out line penetrating the insulating sealing device.

[0017] In a third aspect, an embodiment of the present invention provides a monitoring system for an electric heater for a horizontal well for in-situ extraction of shale oil, comprising: a distributed optical fiber temperature sensor and an electric heater for a horizontal well for in-situ extraction of shale oil as described in the second aspect, wherein the distributed optical fiber temperature sensor is arranged in a horizontal well section of the heating well and is electrically connected to an electrical control cabinet for monitoring the temperature of the horizontal well section and sending a temperature signal to the electrical control cabinet; the electrical control cabinet is used to adjust the heating power and / or heating speed of the electric heater for a horizontal well for in-situ extraction of shale oil according to the temperature monitored by the distributed optical fiber temperature sensor.

[0018] In a fourth aspect, an embodiment of the present invention provides a method for heating an electric heater for in-situ production of shale oil in a horizontal well. The heating method is performed by heating the electric heater for in-situ production of shale oil in a horizontal well according to the second aspect, and may include:

[0019] The electric heating cable for in-situ production of shale oil in horizontal wells is guided by a guide from the wellhead of the target well through the casing to the vertical well section. During the descending process of the electric heating cable in the vertical well section of the target well, the insulating sealing device at the end of the electric heating cable is detected for damage at each descending preset depth;

[0020] The guide is guided by the guide to pass through the deflection section of the target well and then enter the horizontal well section of the target well, so that the hot section of the electric heating cable is arranged in the horizontal well section of the target well;

[0021] After the electric heating cable is laid to the set position, the wellhead of the target well is sealed, the cold section of the electric heating cable is connected to the electrical control cabinet, and the target well is heated using a step-by-step heating method.

[0022] In a fifth aspect, an embodiment of the present invention provides an application of the shale oil in-situ production horizontal well electric heating cable described in the first aspect in a heating well.

[0023] The beneficial effects of the above technical solution provided in the embodiments of the present invention include at least:

[0024] In the embodiment of the present invention, a horizontal well electric heating cable, an electric heater, a monitoring system and a heating method for in-situ shale oil mining are provided. The electric heating cable solves the technical problem that conventional heating cables cannot adapt to the harsh conditions and cannot work in the high temperature, high pressure and highly corrosive shale oil mining environment. Many factors such as its material, service life, and thermal energy consumption directly affect the economic efficiency of shale oil mining by this technology. The electric heating cable is of great significance to improving the strategic succession of oil and gas resources and the guarantee capacity of energy production and supply, promoting the coordinated integration of fossil energy and new energy, and promoting the implementation of major experimental projects such as in-situ conversion of shale oil.

[0025] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0026] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 is a cross-sectional view of an electric heating cable provided in an embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of the structure of the electric heater and the monitoring system provided in the embodiment of the present invention;

[0030] Among them, 1-electric heating cable; 2-electric control cabinet; 3-guide; 4-insulation sealing device; 5-distributed optical fiber temperature sensor;

[0031] 11-cold section; 12-hot section; 13-transition section; 14-sheath layer; 15-insulation layer; 16-core; 17-nickel foil / tin foil. DETAILED DESCRIPTION

[0032] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0033] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "far", "near", "front", "rear" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In order to solve the production needs of high-temperature, high-pressure, and highly corrosive shale oil production environments where conventional heaters cannot operate under such harsh working conditions, an embodiment of the present invention provides a shale oil in-situ production horizontal well electric heating cable, an electric heater, a monitoring system, and a heating method.

[0036] In the embodiment of the present invention, a shale oil in-situ mining horizontal well electric heating cable is provided. Figure 1 and Figure 2 As shown, the electric heating cable 1 may include: a cold section 11 and a hot section 12 connected in sequence, and the hot section 12 is used to be arranged in the horizontal section of the heating well; wherein the cold section 11 and the hot section 12 of the electric heating cable 1 may respectively include a sheath layer 14, an insulating layer 15 and a core 16 from the outside to the inside; the sheath layer 14 and the core 16 are coaxially arranged, and the insulating layer 15 is distributed between the sheath layer 14 and the core 16; the material of the sheath layer 14 of the cold section 11 is an austenitic alloy, and the material of the sheath layer 14 of the hot section 12 is a nickel-based alloy.

[0037] The above-mentioned electric heating cable provided in the embodiment of the present invention has an outermost sheath layer of corrosion-resistant high-strength metal material, a middle insulation layer of high-temperature resistant, high thermal conductivity insulation material, and an internal wire core (heating wire core) of high resistance, high thermal conductivity material. The middle insulation layer is evenly and densely distributed between the sheath layer and the wire core, and the three form a compact, dense integrated structure. In this embodiment, the electric heating cable screens the outermost sheath layer of the cold section and the hot section according to different environments. In the embodiment of the present invention, the electric heating cable located in the vertical well is the cold section, and the electric heating cable located in the horizontal well section is the hot section. Since there are fewer corrosive media, lower pressure, and lower temperature in the vertical well, the material of the cold section sheath layer in the embodiment of the present invention is preferably austenitic alloy; since the horizontal well section contains corrosive media such as H2S, CO2, H2, H2O, and has high temperature and high pressure, the material of the hot section sheath layer in the embodiment of the present invention is preferably nickel-based alloy.

[0038] It should be noted that, refer to Figure 2 As shown, Figure 2It is shown in the figure that the electric heating cable 1 in this embodiment also includes a transition section 13. Since the transition section 13 is located in the drilling inclination section, the cable in this section has the same structure as the cold section 11, but is named as a transition section due to its different location. Technical personnel in this field should not misunderstand this.

[0039] The above-mentioned electric heating cable provided in the embodiment of the present invention solves the technical problem that conventional heating cables cannot adapt to the harsh conditions and cannot work in the high-temperature, high-pressure and highly corrosive shale oil mining environment. Many factors such as its material, service life, and thermal energy consumption directly affect the economic efficiency of shale oil mining by this technology. The electric heating cable is of great significance to improving the strategic succession of oil and gas resources and the guarantee capacity of energy production and supply, promoting the coordinated integration of fossil energy and new energy, and promoting the implementation of major experimental projects such as the in-situ conversion of shale oil.

[0040] In an alternative embodiment, referring to Figure 1 As shown, the base material of the core 16 is a copper-nickel alloy, and the surface of the copper-nickel alloy is plated with cerium or palladium. The core in this embodiment is a heating core with high resistance and high thermal conductivity after being plated with cerium or palladium, and its base material is preferably a copper-nickel alloy.

[0041] In another alternative embodiment, referring to Figure 1 As shown, the outer side of the wire core 16 is wrapped with nickel foil 17 or tin foil 17. In order to better ensure the performance of the insulating layer and prevent copper ions from diffusing into the magnesium oxide layer at high temperature in the embodiment of the present invention, Ni foil or tin foil is placed between the insulating layer and the wire core, that is, nickel foil 17 or tin foil 17 is wrapped on the outer side of the wire core 16.

[0042] In another optional embodiment, the material of the insulating layer 15 is high-purity magnesium oxide and high-purity zirconium oxide; the mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer 15, and the mass fraction of the high-purity zirconium oxide is 0 to 50% of the insulating layer 15; or, the material of the insulating layer 15 is high-purity magnesium oxide and high-purity manganese oxide; the mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer 15, and the mass fraction of the high-purity manganese oxide is 0 to 50% of the insulating layer 15; or, the material of the insulating layer 15 is high-purity magnesium oxide, high-purity zirconium oxide and high-purity manganese oxide, the mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer 15, the mass fraction of the high-purity zirconium oxide is 0 to 50% of the insulating layer 15, and the mass fraction of the high-purity manganese oxide is 0 to 50% of the insulating layer 15.

[0043] The above-mentioned insulating layer in the embodiment of the present invention is a high temperature resistant and high thermal conductivity insulating material including high purity magnesium oxide, and at least one of high purity zirconium oxide and manganese oxide, the mass fraction of high purity magnesium oxide is 50-100%, the mass fraction of high purity zirconium oxide is 0-50%, and the mass fraction of high purity manganese oxide is 0-50%. The insulating layer can not only separate the wire core from the metal of the sheath layer, but also play a role in heat conduction and protection, which can further improve the service life of the electric heating cable in the embodiment of the present invention.

[0044] In another alternative embodiment, referring to Figure 1 As shown, there are three cores 16 in the electric heating cable 1, and the tail ends of the three cores 16 are connected in a star shape to form tail star welding points. In this embodiment, the heating core includes three separate heating conductor cores, and the tail ends of the three conductor cores are connected in a star shape to form tail star welding points.

[0045] Based on the same inventive concept, an electric heater for horizontal wells for in-situ production of shale oil is also provided in the embodiment of the present invention. Figure 2 As shown, the electric heater may include: an electrical control cabinet 2, a guide 3 and the above-mentioned shale oil in-situ production horizontal well electric heating cable 1; wherein the electrical control cabinet 2 is connected to the cold section 11 of the electric heating cable 1, and is used to control the output voltage of the electric heating cable 1; the guide 3 is connected to the hot section 12 of the electric heating cable 1, and is used to guide the electric heating cable 1 from the casing into the heating well.

[0046] It should be noted that when the electrical control cabinet in this embodiment is working, it first increases the 380V power voltage to 10KV-20KV, and then transforms it to 1kV-3kV to power the cold section of the electric heating cable. It should be further noted that when the electric heater in this embodiment is in use, all equipment needs to be grounded to ensure that the electric heater can protect the safety of construction workers in the event of an electrical failure. The guide in this embodiment is an injection head guide, which not only provides the vertical force required for lifting and sending down the cable, but also provides the power for the cable to move forward in the horizontal direction. The electrical control cabinet in this embodiment includes an active switching element that can receive feedback and adjust the heating power of the heater in real time.

[0047] In this embodiment, the end of the cold section of the electric heating cable is connected to the electrical control cabinet (external power supply), and the hot section of the electric heating cable is connected to the guide. When in use, it is pulled by the guide and enters the heating well through the casing, so that the hot section of the electric heating cable lies flat in the horizontal well section. The output voltage is controlled by the electrical control cabinet to make the electric heating cable work.

[0048] In another alternative embodiment, referring to Figure 2As shown, the electric heater may further include: two insulating sealing devices 4, one insulating sealing device 4 is sleeved at the end of the hot section 12 and connected to the guide 3; the other insulating sealing device 4 is sleeved at the end of the cold section 11, and is respectively connected to the cold section 11 and the electrical control cabinet 2 through a power lead wire passing through the insulating sealing device 4.

[0049] In the embodiment of the present invention, by arranging insulating sealing devices at the two ends of the electric heating cable, the electric heating cable can be effectively protected during the lowering or lifting process. The insulating sealing device in this embodiment is coaxially arranged with the electric heating cable, and the diameter of the insulating sealing device is larger than the diameter of the sheath layer of the electric heating cable.

[0050] Based on the same inventive concept, an electric heater monitoring system for horizontal wells for in-situ production of shale oil is also provided in the embodiment of the present invention. Figure 2 As shown, the monitoring system may include: a distributed optical fiber temperature sensor 5 and the above-mentioned electric heater for horizontal wells for in-situ extraction of shale oil. The distributed optical fiber temperature sensor 5 is used to be arranged in the horizontal well section of the heating well and is electrically connected to the electrical control cabinet 2 to monitor the temperature of the horizontal well section and send the temperature signal to the electrical control cabinet 2; the electrical control cabinet 2 is used to adjust the heating power and / or heating speed of the electric heater for horizontal wells for in-situ extraction of shale oil according to the temperature monitored by the distributed optical fiber temperature sensor 5.

[0051] In the embodiment of the present invention, optical fiber monitoring is adopted, and the optical fiber is distributed on the surface of the horizontal section casing in a cross-shaped distribution to collect real-time temperature. The temperature is fed back to the electrical control cabinet, and the output voltage is adjusted in real time. The above-mentioned distributed optical fiber temperature sensor is an optical instrument for temperature perception, and a single optical fiber is used to simultaneously realize temperature monitoring and signal transmission. It can detect tiny temperature changes, provide accurate and continuous temperature data in real time, and can realize real-time fast multi-point measurement of spatial temperature distribution over a large range and long distance.

[0052] Based on the same inventive concept, an embodiment of the present invention further provides a heating method for an electric heater for in-situ production of shale oil horizontal wells. The heating method is performed according to the above-mentioned electric heater for in-situ production of shale oil horizontal wells. The heating method may include the following steps:

[0053] In the first step, the electric heating cable for in-situ production of shale oil in horizontal wells is guided by a guide from the wellhead of the target well through the casing into the vertical well section. During the descent of the electric heating cable in the vertical well section of the target well, the insulation sealing device at the end of the electric heating cable is detected for damage at each descent to a preset depth. In the embodiment of the present invention, the insulation resistance (insulation sealing device) of the heater can be detected every 100 meters the heater descends to ensure that the front end of the heater is not damaged.

[0054] In the second step, the guide is used to guide the electric heating cable through the deflection section of the target well and then enter the horizontal well section of the target well, so that the hot section of the electric heating cable is arranged in the horizontal well section of the target well.

[0055] The third step is to seal the wellhead of the target well after the electric heating cable is laid to the set position, connect the cold section of the electric heating cable to the electrical control cabinet, and heat the target well using a step-by-step heating method.

[0056] Based on the same inventive concept, an embodiment of the present invention also provides an application of an electric heating cable for in-situ production of shale oil horizontal wells in a heating well.

[0057] The application of the above-mentioned electric heater, heating method and electric heating cable in the embodiments of the present invention in the heating well, its beneficial effects and detailed description can refer to the relevant introduction of the above-mentioned electric heating cable, and the embodiments of the present invention will not be repeated here.

[0058] Obviously, various changes and modifications may be made to the present invention by those skilled in the art without departing from the spirit and scope of the present invention. The present disclosure is not limited to the precise structure described above and shown in the accompanying drawings, and various changes and modifications may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims. Thus, if these changes and modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. An electric heating cable for horizontal wells for in-situ mining of shale oil, characterized in that: The electric heating cable comprises: a cold section and a hot section connected in sequence, wherein the hot section is used to be arranged in a horizontal well section of a heating well; wherein the cold section and the hot section of the electric heating cable respectively comprise a sheath layer, an insulating layer and a core from the outside to the inside; the sheath layer and the core are coaxially arranged, and the insulating layer is distributed between the sheath layer and the core; The material of the jacket layer of the cold section is an austenitic alloy, and the material of the jacket layer of the hot section is a nickel-based alloy.

2. The electric heating cable according to claim 1, characterized in that: The base material of the wire core is a copper-nickel alloy, and the surface of the copper-nickel alloy is plated with cerium or palladium.

3. The electric heating cable according to claim 2, characterized in that: The outer side of the wire core is wrapped with nickel foil or tin foil.

4. The electric heating cable according to claim 1, characterized in that: The insulating layer is made of high-purity magnesium oxide and high-purity zirconium oxide; the mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer, and the mass fraction of the high-purity zirconium oxide is 0% to 50% of the insulating layer; or, The insulating layer is made of high-purity magnesium oxide and high-purity manganese oxide; the mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer, and the mass fraction of the high-purity manganese oxide is 0 to 50% of the insulating layer; or, The insulating layer is made of high-purity magnesium oxide, high-purity zirconium oxide and high-purity manganese oxide. The mass fraction of the high-purity magnesium oxide is 50% to 100% of the insulating layer, the mass fraction of the high-purity zirconium oxide is 0 to 50% of the insulating layer, and the mass fraction of the high-purity manganese oxide is 0 to 50% of the insulating layer.

5. The electric heating cable according to any one of claims 1 to 4, characterized in that: There are three wire cores in the electric heating cable, and the tail ends of the three wire cores are connected in a star shape to form tail end star connection welding points.

6. An electric heater for horizontal wells for in-situ mining of shale oil, characterized in that: include: An electrical control cabinet, a guide, and an electric heating cable for horizontal wells for in-situ production of shale oil according to any one of claims 1 to 5; Among them, the electrical control cabinet is connected to the cold section of the electric heating cable to control the output voltage of the electric heating cable; the guide is connected to the hot section of the electric heating cable to guide the electric heating cable into the heating well through the casing.

7. The electric heater according to claim 6, characterized in that: Also includes: Two insulating sealing devices, one of which is sleeved on the end of the hot section and connected to the guide; Another insulating sealing device is sleeved on the end of the cold section, and is connected to the cold section and the electrical control cabinet respectively through a power lead-out line penetrating the insulating sealing device.

8. An electric heater monitoring system for horizontal wells for in-situ shale oil production, characterized in that: include: A distributed optical fiber temperature sensor and an electric heater for horizontal wells for in-situ extraction of shale oil as described in claim 6 or 7, wherein the distributed optical fiber temperature sensor is used to be arranged in the horizontal well section of the heating well and is electrically connected to the electrical control cabinet, so as to monitor the temperature of the horizontal well section and send the temperature signal to the electrical control cabinet; the electrical control cabinet is used to adjust the heating power and / or heating speed of the electric heater for horizontal wells for in-situ extraction of shale oil according to the temperature monitored by the distributed optical fiber temperature sensor.

9. A heating method for an electric heater for horizontal wells in situ mining of shale oil, characterized in that: The heating method is to heat the shale oil in-situ mining horizontal well using the electric heater according to claim 6 or 7, comprising: The electric heating cable for in-situ production of shale oil in horizontal wells is guided by a guide from the wellhead of the target well through the casing to the vertical well section. During the descending process of the electric heating cable in the vertical well section of the target well, the insulating sealing device at the end of the electric heating cable is detected for damage at each descending preset depth; The guide is guided by the guide to pass through the deflection section of the target well and then enter the horizontal well section of the target well, so that the hot section of the electric heating cable is arranged in the horizontal well section of the target well; After the electric heating cable is laid to the set position, the wellhead of the target well is sealed, the cold section of the electric heating cable is connected to the electrical control cabinet, and the target well is heated by a step-by-step heating method.

10. Use of an electric heating cable for horizontal wells for in-situ production of shale oil as claimed in any one of claims 1 to 5 in a heating well.

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