Downhole electric heating device integrating convection heating and in-situ liquid drainage and using method thereof

Abstract

The invention relates to an underground electric heating device integrating convection heating and in-situ liquid drainage and a using method thereof.The device comprises an upper connector, a lower connector, a heating pipe body, a liquid drainage pipe body, a one-way valve, a heating assembly and a Tesla valve, and the heating pipe body and the liquid drainage pipe body are arranged between the upper connector and the lower connector side by side; the wiring hole of the upper joint is communicated with the hot air outlet of the lower joint through the heating pipe body, and the medium exchange port of the upper joint is communicated with the fluid medium inlet of the lower joint through the liquid discharge pipe body; the one-way valve is arranged at the joint of the bottom end of the liquid discharge pipe body and the fluid medium inlet of the lower joint; the heating assembly and the Tesla valve are arranged in the heating pipe body and on the lower portion of the heating pipe body respectively. According to the underground electric heating device integrating convective heating and in-situ liquid drainage and the using method thereof, in-situ heating in a well can be achieved, in-situ liquid drainage in the well can also be achieved, and therefore underground heating and in-well liquid drainage can be conducted step by step.

Description

Technical Field

[0001] The present invention relates to the technical field of heaters, and in particular to a downhole electric heating device integrating convection heating and in-situ drainage and a method for using the device. Background Art

[0002] Downhole heaters are commonly used in the fields of in-situ pyrolysis of oil shale, in-situ pyrolysis of oil-rich coal, thermal recovery of heavy oil, and oil sand mining. According to the different sources of heat generated in the heater, the heater can be divided into steam heaters, combustion heaters, and electric heaters. Among them, the combustion heater has extremely high requirements for its control process, and its stability in underground use is far inferior to that of the electric heater. Electric heaters can be further subdivided into resistance heating and electromagnetic induction heating. The electric heaters commonly used in experiments or industry are generally conductive resistance heating, and heating and drainage are carried out using different equipment, which often has the disadvantages of poor drainage effect, easy damage to the heater, and low heating efficiency. Summary of the invention

[0003] In view of the above problems, the purpose of the present invention is to provide a downhole electric heating device integrating convection heating and in-situ drainage and a method of using the same, so as to solve the problem that the current downhole heating devices have low heating efficiency and cannot perform in-situ drainage.

[0004] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention discloses a downhole electric heating device integrating convection heating and in-situ drainage, comprising an upper joint, a lower joint, a heating pipe body, a drainage pipe body, a one-way valve, a heating component and a Tesla valve. The left and right sides of the upper joint are respectively provided with a wiring hole and a medium exchange port, and the wiring hole and the medium exchange port are connected through a transverse channel, and the left and right sides of the lower joint are respectively provided with a hot gas outlet and a fluid medium inlet; The heating pipe body and the drain pipe body are arranged side by side between the upper joint and the lower joint, and the upper joint is connected to the hot air outlet of the lower joint through the heating pipe body, and the medium exchange port of the upper joint is connected to the fluid medium inlet of the lower joint through the drain pipe body; The one-way valve is arranged at the joint between the bottom end of the discharge pipe body and the fluid medium inlet of the lower joint, so as to ensure that the medium can only flow upward from the fluid medium inlet of the lower joint into the discharge pipe body and cannot flow in the reverse direction; The heating component and the Tesla valve are respectively arranged at the upper part and the lower part of the heating tube body; Wherein, the medium exchange port of the upper joint is used for connecting the oil pipe; The Tesla valve can prevent liquid from flowing into the interior of the heating tube from the hot gas outlet of the lower joint, but can allow the gas in the heating tube to flow out from the hot gas outlet; The heating component is used to heat the gas flowing through it.

[0005] Furthermore, the downhole electric heating device also includes a ferrule, and the ferrule is sealed and arranged at the opening of the wiring hole of the upper joint.

[0006] Furthermore, the heating component includes a heating rod, the top of the heating rod is provided with a terminal head, the center of the ferrule is provided with a cable hole, the cable hole of the ferrule is provided with a cable, and the cable is connected to the terminal head of the heating rod.

[0007] Furthermore, the heating rod is sequentially covered with a plurality of groups of mutually parallel spiral baffles from top to bottom.

[0008] Furthermore, a first temperature sensor and a second temperature sensor are respectively provided at the air outlet and the air inlet of the heating tube body; The first temperature sensor and the second temperature sensor are provided with a display, and the display is connected to the first temperature sensor and the second temperature sensor via a first signal line and a second signal line, respectively.

[0009] Furthermore, the ferrule is further provided with a first signal line tube hole and a second signal line tube hole, and the first signal line tube hole and the second signal line tube hole are respectively located on both sides of the cable hole; The first signal line tube hole and the second signal line tube hole are respectively inserted with a first signal line tube and a second signal line tube, and the bottom ends of the first signal line tube and the second signal line tube are respectively extended into the air outlet and the air inlet of the heating tube body; A first temperature sensor and a second temperature sensor are respectively disposed at the bottom ends of the first signal line tube and the second signal line tube; A first signal line and a second signal line are respectively passed through the first signal line tube and the second signal line tube, the bottom ends of the first signal line and the second signal line are respectively connected to the first temperature sensor and the second temperature sensor, and the top ends of the first signal line and the second signal line respectively extend upward from the first signal line tube and the second signal line tube and expose the line ends; The exposed ends of the first signal line and the second signal line are respectively connected to the display; Wherein, the first temperature sensor and the second temperature sensor are used to respectively test and detect the temperature at the air outlet and the air inlet of the heating tube in real time; The display is used to display the temperatures detected by the first temperature sensor and the second temperature sensor in real time.

[0010] Furthermore, the upper joint is butted with the top end of the heating tube body through a left short circuit, and the bottom end of the heating tube body is butted with the hot air outlet of the lower joint; The medium exchange port of the upper joint is butted with the top end of the liquid discharge tube body through a right short circuit, and the bottom end of the liquid discharge tube body is butted with the fluid medium inlet of the lower joint.

[0011] Furthermore, the heating tube body comprises an upper heating tube body and a lower heating tube body, and the bottom end of the upper heating tube body and the top end of the lower heating tube body are connected together by threads; The heating component is arranged on the upper part of the heating tube body; The Tesla valve is arranged at the lower part of the heating tube body.

[0012] In a second aspect, the present invention further discloses a method for using the above-mentioned downhole electric heating device integrating convection heating and in-situ drainage, comprising: When the liquid is discharged in situ, the liquid at the bottom of the well will be blocked by the Tesla valve after the hot gas from the lower joint comes out, and can only pass through the fluid medium inlet of the lower joint, pass upward through the one-way valve, enter the discharge pipe body, continue to move upward, enter the oil pipe through the medium exchange port of the upper joint, and finally be discharged to the ground through the oil pipe; When gas injection heating is required, normal temperature gas is injected into the medium exchange port of the upper joint through the oil pipe, and a part of the gas moves downward to the bottom end of the discharge pipe body and the joint of the fluid medium inlet of the lower joint, and is blocked by the one-way valve; the remaining gas enters the heating pipe body connected to the upper joint through the transverse channel and is heated by the heating component to become high temperature gas; After the high-temperature gas passes through the Tesla valve, it passes through the hot gas outlet of the lower joint and finally reaches the bottom of the well.

[0013] Wherein, during the process of injecting gas into the bottom of the well for heating, the first temperature sensor and the second temperature sensor respectively detect the temperatures at the gas outlet and the gas inlet of the heating pipe body in real time; The display displays the temperatures tested by the first temperature sensor and the second temperature sensor in real time respectively.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (I) The present invention discloses a downhole electric heating device integrating convection heating and in-situ drainage and a method for using the device, wherein the device comprises an upper joint, a lower joint, a heating pipe body, a drainage pipe body, a one-way valve, a heating component and a Tesla, wherein the heating pipe body and the drainage pipe body are arranged side by side between the upper joint and the lower joint, and the upper joint is connected to the hot air hole of the lower joint through the heating pipe body, and the medium exchange port of the upper joint is connected to the fluid medium inlet of the lower joint through the drainage pipe body; the one-way valve is arranged at the joint between the bottom end of the drainage pipe body and the fluid medium inlet of the lower joint, and the heating component and the Tesla valve are respectively arranged inside and below the heating pipe body. When draining in situ, the liquid at the bottom of the well will be blocked by the Tesla valve after reaching the hot gas outlet of the lower joint, and can only pass through the fluid medium inlet of the lower joint, pass upward through the one-way valve, enter the drainage pipe body, continue to move upward, enter the oil pipe through the medium exchange port of the upper joint, and finally be discharged to the ground through the oil pipe; when in-situ gas injection heating is required, normal temperature gas is injected into the medium exchange port of the upper joint through the oil pipe, and a part of it moves downward to the bottom end of the drainage pipe body and the joint with the fluid medium inlet of the lower joint, and is blocked by the one-way valve; the remaining gas enters the upper joint through the horizontal channel to connect to the heating pipe body, is heated by the heating component, and becomes high-temperature gas; after passing through the Tesla valve, the high-temperature gas passes through the hot gas outlet of the lower joint and finally reaches the well. The present invention discloses an underground electric heating device integrating convection heating and in-situ drainage and a method of using the device, which can not only realize in-situ drainage underground, but also perform in-situ heating on the basis of in-situ drainage, thereby realizing that underground heating and underground drainage are carried out step by step through the same device, greatly extending the service life of the underground heating device, solving the problem that the heating device and drainage device used separately are too large in size and have few usage scenarios, and indirectly increasing the in-situ mining depth of unconventional energy.

[0015] (II) The present invention discloses a downhole electric heating device integrating convection heating and in-situ drainage, which reduces the size of the heater, improves the heating efficiency of the heating component, and is suitable for deeper unconventional energy mining. In addition, by diverting the downhole gas and the return liquid, downhole heating and underground liquid return are carried out in steps in the same device, protecting the downhole heating device from damage by the downhole liquid, greatly reducing the probability of replacing and maintaining the heater and reducing the work intensity of going up and down the well, increasing the effective heating time of in-situ heat injection, improving practicality, and reducing process costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A longitudinal cross-sectional view of a downhole electric heating device provided in Example 1 of the present invention; Figure 2 for Figure 1 A partial enlarged view of middle A; Figure 3 An exploded diagram of a downhole electric heating device provided in Example 1 of the present invention; Figure 4 A schematic diagram of the structure of a heating component provided in Embodiment 1 of the present invention; Figure 5 A schematic diagram of the structure of a Tesla valve provided in Example 1 of the present invention; Figure 6 A schematic diagram of a medium (discharge fluid) flowing in a downhole electric heating device under a bottom hole liquid flowback state provided in Example 2 of the present invention; Figure 7 This is a schematic diagram of the flow of a medium (gas) in a downhole heating device during gas injection and heating at the bottom of a well, as provided in Example 2 of the present invention.

[0017] Description of reference numerals: 100 - oil pipe; 1-upper connector, 10-lateral channel, 11-wiring hole, 12-medium exchange port, 2-lower joint, 21-hot gas outlet, 22-fluid medium inlet; 31-left short circuit, 32-right short circuit; 41-heating tube body, 411-heating tube body upper part, 412-heating tube body lower part; 42-drain pipe body, 421-upper part of drain pipe body, 422-lower part of drain pipe body; 5- One-way valve; 60-cable, 61-ferrule, 62-heating component, 620-connecting head, 621-heating rod, 622-spiral baffle; 63-Tesla valve, 631-Tesla valve inlet, 632-Tesla valve outlet; 71 - first signal line tube, 72 - second signal line tube, 81 - first temperature sensor, 82 - second temperature sensor. DETAILED DESCRIPTION

[0018] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0019] In order to solve the problem that the heating efficiency of the heating component of the current downhole heater is low and inability to perform in-situ drainage, the present invention discloses a downhole electric heating device integrating convection heating and in-situ drainage and a method of using the same, wherein the device comprises an upper joint, a lower joint, a heating tube body, a drainage tube body, a one-way valve, a heating component and a Tesla valve, the heating tube body and the drainage tube body are arranged side by side between the upper joint and the lower joint, and the wiring hole of the upper joint is connected to the hot air hole of the lower joint through the heating tube body, and the medium exchange hole of the upper joint is connected to the fluid medium hole of the lower joint through the drainage tube body; the one-way valve is arranged at the joint between the bottom end of the drainage tube body and the fluid medium hole of the lower joint, and the heating component and the Tesla valve are respectively arranged at the upper and lower parts of the heating tube body. When the underground water flows back to the bottom of the well, the liquid at the bottom of the well will be blocked by the Tesla valve after reaching the hot air hole of the lower joint, and can only pass through the fluid medium hole of the lower joint, pass through the one-way valve upward, enter the drainage pipe body, continue to move upward, enter the oil pipe through the medium exchange hole of the upper joint, and finally be discharged to the ground through the oil pipe; when it is necessary to inject gas to heat the bottom of the well, normal temperature gas is injected into the medium exchange hole of the upper joint through the oil pipe, and a part of it moves downward to the bottom end of the drainage pipe body and the joint with the fluid medium hole of the lower joint, and is blocked by the one-way valve; the remaining gas enters the wiring hole of the upper joint through the transverse channel; the normal temperature gas is heated by the heating component in the heating pipe body and becomes high-temperature gas; after the high-temperature gas passes through the Tesla valve, it passes through the hot air hole of the lower joint and finally reaches the bottom of the well. The present invention discloses a downhole electric heating device integrating convection heating and in-situ drainage and a method of using the same, which can not only realize in-situ drainage at the wellhead, but also perform in-situ heating based on the in-situ drainage wellhead, thereby realizing downhole heating and underground water gushing at the same position, greatly extending the service life of the downhole heating device, solving the problem of the heating component being too large and having few usage scenarios, and indirectly increasing the exploitable depth of unconventional energy.

[0020] Example 1: A downhole electric heating device integrating convection heating and in-situ drainage Embodiment 1 of the present invention provides a downhole electric heating device integrating convection heating and in-situ drainage, and its structure is described in detail below with reference to the accompanying drawings.

[0021] refer to Figures 1 to 5 The downhole electric heating device integrating convection heating and in-situ drainage includes an upper joint 1, a lower joint 2, a left short circuit 31, a right short circuit 32, a heating pipe body 41, a drainage pipe body 42, a one-way valve 5, a heating component 62 and a Tesla valve 63.

[0022] The upper joint 1 is provided with a wiring hole 11 and a medium exchange port 12 on the left and right sides respectively, and the wiring hole 11 and the medium exchange port 12 are connected through a transverse channel 10, and the lower joint 2 is provided with a hot gas outlet 21 and a fluid medium inlet 22 on the left and right sides respectively; The heating pipe body 41 and the drain pipe body 42 are arranged side by side between the upper joint 1 and the lower joint 2, and the upper joint 1 is connected to the hot air outlet 21 of the lower joint 2 through the heating pipe body 41, and the medium exchange port 12 of the upper joint 1 is connected to the fluid medium inlet 22 of the lower joint 2 through the drain pipe body 42; The one-way valve 5 is arranged at the joint between the bottom end of the drain pipe body 42 and the fluid medium inlet 22 of the lower joint 2, so as to ensure that the medium can only flow upward from the fluid medium hole inlet 22 of the lower joint 2 into the drain pipe body 42 and cannot flow in the reverse direction; The heating component 62 and the Tesla valve 63 are respectively arranged at the upper part and the lower part of the heating tube body 41; The medium exchange port 12 of the upper joint 1 is used for connecting with the oil pipe 100; The Tesla valve 63 can prevent the liquid from flowing from the hot gas outlet 21 of the lower joint 2 into the interior of the heating pipe body 41, but can allow the gas in the heating pipe body 41 to pass through and enter the well; The heating component 62 is used to heat the gas flowing therethrough.

[0023] When the liquid is discharged in situ, after the liquid at the bottom of the well reaches the hot gas outlet 21 of the lower joint 2, it will be blocked by the Tesla valve 63 and can only pass through the fluid medium inlet 22 of the lower joint 2, pass upward through the one-way valve 5, enter the liquid discharge pipe body 42, continue to move upward, enter the oil pipe 100 through the medium exchange port 12 of the upper joint 1, and finally be discharged to the ground through the oil pipe 100; When in-situ gas injection is required, normal temperature gas is injected into the medium exchange port 12 of the upper joint 1 through the oil pipe 100, and a part of the gas moves downward to the bottom end of the drainage pipe body 42 and the joint with the fluid medium inlet 22 of the lower joint 2, and is blocked by the one-way valve 5; the remaining gas enters the heating pipe body 41 through the transverse channel 10 and is heated by the heating component 62 to become high temperature gas; After passing through the Tesla valve 63, the high-temperature gas passes through the hot gas outlet 21 of the lower joint 2 and finally reaches the bottom of the well.

[0024] In order to prevent gas or liquid from flowing out from the opening of the wiring hole 11 of the upper connector 1 , the downhole electric heating device further comprises a ferrule 61 , which can pass through the cable and seal the opening of the wiring hole 11 of the upper connector 1 .

[0025] In order to achieve the heating effect by energizing the heating rod 621, the heating component 62 includes a heating rod 621, the top of the heating rod 621 is provided with a terminal head 620, the center of the ferrule 61 is provided with a cable hole, the cable hole of the ferrule 61 is passed with a cable 60, and the cable 60 is connected to the terminal head 620 of the heating rod 621.

[0026] The heating component 62 is an electric heating rod 621, which heats the shell-side air to an optimal state by enhancing heat transfer. Common heating components use magnesium oxide as the insulation material and stainless steel as the outer armor material. The heat exchange structure adopts a spiral baffle structure.

[0027] In a specific implementation of the baffle structure, the heating rod 621 is sequentially covered with a plurality of groups of mutually parallel spiral baffles 622 from top to bottom.

[0028] The heating rod 621 and the plurality of spiral baffles 622 are integrally formed.

[0029] During the process of injecting gas into the bottom of the well for heating, in order to detect whether the temperatures at the air outlet and the air inlet of the heating pipe body 41 meet the requirements, the air outlet and the air inlet of the heating pipe body 41 are respectively provided with a first temperature sensor 81 and a second temperature sensor 82, and the first temperature sensor 81 and the second temperature sensor 82 are configured with a display, and the display is connected to the first temperature sensor 81 and the second temperature sensor 82 respectively through a first signal line and a second signal line.

[0030] As a specific implementation, the ferrule 61 is further provided with a first signal line tube hole and a second signal line tube hole, and the first signal line tube hole and the second signal line tube hole are respectively located on both sides of the cable hole; The first signal line tube hole and the second signal line tube hole are respectively inserted with a first signal line tube 71 and a second signal line tube 72, and the bottom ends of the first signal line tube 71 and the second signal line tube 72 extend into the air outlet and the air inlet of the heating tube body 41 respectively; A first temperature sensor 81 and a second temperature sensor 82 are respectively disposed at the bottom ends of the first signal line tube 71 and the second signal line tube 72; A first signal line and a second signal line are respectively passed through the first signal line tube 71 and the second signal line tube 72. The bottom ends of the first signal line and the second signal line are respectively connected to the first temperature sensor 81 and the second temperature sensor 82. The top ends of the first signal line and the second signal line respectively extend upward from the first signal line tube 71 and the second signal line tube 72 and expose the line ends. The exposed ends of the first signal line tube 71 and the second signal line tube 72 are respectively connected to the display; The first temperature sensor 81 and the second temperature sensor 82 are used to detect the temperatures of the air outlet and the air inlet of the heating tube body 41 in real time, respectively; The display is used to display the temperatures tested by the first temperature sensor 81 and the second temperature sensor 82 in real time.

[0031] As a specific implementation method for connecting the upper joint 1 to the heating tube body 41 and the drainage tube body 42 respectively, the upper joint 1 is connected to the top end of the heating tube body 41 through the left short circuit 31, and the bottom end of the heating tube body 41 is connected to the hot air outlet 21 of the lower joint 2; the medium exchange port 12 of the upper joint 1 is connected to the top end of the drainage tube body 42 through the right short circuit 32, and the bottom end of the drainage tube body 42 is connected to the fluid medium inlet 22 of the lower joint 2.

[0032] More specifically, the heating tube body 41 includes a heating tube body upper part 411 and a heating tube body lower part 412, the bottom end of the heating tube body upper part 411 and the top end of the lower heating tube body part 412 are connected together by threads; the heating component 62 is arranged in the heating tube body part 411; the Tesla valve 63 is arranged in the heating tube body lower part 412.

[0033] Similarly, the drain tube body 42 includes an upper drain tube body portion 421 and a lower drain tube body portion 422, and the bottom end of the upper drain tube body portion 421 and the top end of the lower drain tube body portion 422 are threadedly connected together; the one-way valve 5 is arranged at the joint between the bottom end of the lower drain tube body portion 422 and the fluid medium inlet 22 of the lower joint 2.

[0034] Specifically, the upper joint 1 is a multifunctional conversion joint, which is a prior art.

[0035] Specifically, the one-way valve 5 is a one-way gravity valve, which is a prior art.

[0036] The Tesla valve 63, also called a Tesla directional valve, comprises a Tesla valve inlet 631 and a Tesla valve outlet 632. Figure 5 As shown, it is a one-way flow valve proposed by Serbian-American scientist Nikola Tesla and named after himself. The magic lies in that it has no moving parts as a whole, and only uses the spatial structure to change the gas flow. It can achieve the one-way flow characteristics of the fluid without any extra mechanical parts. It is an existing technology and will not be described here.

[0037] Example 2: Method for using a downhole electric heating device integrating convection heating and in-situ drainage Embodiment 2 of the present invention provides a method for using a downhole electric heating device integrating convection heating and in-situ drainage, using the downhole electric heating device integrating convection heating and in-situ drainage of embodiment 1, the method comprises the following steps: refer to Figure 6When the liquid is discharged in situ, after the liquid at the bottom of the well reaches the hot gas outlet 21 of the lower joint 2, it will be blocked by the Tesla valve 63 and can only pass through the fluid medium inlet 22 of the lower joint 2, pass through the one-way valve 5 upward, enter the liquid discharge pipe body 42, continue to move upward, enter the oil pipe 100 through the medium exchange port 12 of the upper joint 1, and finally be discharged to the ground through the oil pipe 100; Among them, since there is residual gas in the downward gas flow channel formed by the heating pipe body 41 and the hot gas outlet 21 to form air pressure, after the liquid enters the medium exchange inlet 12 of the upper joint 1, only a small amount will enter the heating pipe body 41 through the transverse channel 10, and will be blocked by the air pressure and cannot flow downward. Therefore, most of the liquid will directly enter the oil pipe 100 through the medium exchange port 12 of the upper joint 1, and finally be discharged to the ground through the oil pipe 100.

[0038] refer to Figure 7 When in-situ gas injection heating is required, normal temperature gas is injected into the medium exchange port 12 of the upper joint 1 through the oil pipe 100, and a part of the gas moves downward to the bottom end of the drainage pipe body 42 and the joint with the fluid medium inlet 22 of the lower joint 2, and is blocked by the one-way valve 5; the remaining gas enters the heating pipe body 41 of the upper connecting joint 1 through the transverse channel 10, and is heated by the heating component 62 to become high-temperature gas; After passing through the Tesla valve 63, the high-temperature gas passes through the hot gas outlet 21 of the lower joint 2 and finally reaches the bottom of the well.

[0039] The first temperature sensor 81 and the second temperature sensor 82 respectively measure the temperature of the air outlet and the air inlet of the heating tube 41 in real time. During the process of injecting gas into the bottom of the well for heating, the first temperature sensor 81 and the second temperature sensor 82 respectively detect the temperatures at the air outlet and the air inlet of the heating pipe body 41 in real time; the display respectively displays the temperatures tested by the first temperature sensor 81 and the second temperature sensor 82 in real time.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A downhole electric heating device integrating convection heating and in-situ drainage, characterized in that: It comprises an upper joint (1), a lower joint (2), a heating pipe body (41), a liquid discharge pipe body (42), a one-way valve (5), a heating component (62) and a Tesla valve (63), The upper joint (1) is provided with a wiring hole (11) and a medium exchange port (12) on the left and right sides respectively, and the wiring hole (11) and the medium exchange port (12) are connected via a transverse channel (10), and the lower joint (2) is provided with a hot air outlet (21) and a fluid medium inlet (22) on the left and right sides respectively; The heating tube body (41) and the drainage tube body (42) are arranged side by side between the upper joint (1) and the lower joint (2), and the wiring hole (11) of the upper joint (1) is connected to the hot air outlet (21) of the lower joint (2) through the heating tube body (41), and the medium exchange port (12) of the upper joint (1) is connected to the fluid medium inlet (22) of the lower joint (2) through the drainage tube body (42); The one-way valve (5) is arranged at the joint between the bottom end of the drainage pipe body (42) and the fluid medium inlet (22) of the lower joint (2), so as to ensure that the bottom hole liquid medium can only flow upward from the fluid medium inlet (22) of the lower joint (2) into the drainage pipe body (42) and cannot flow in the reverse direction; The heating component (62) and the Tesla valve (63) are respectively arranged at the upper part and the lower part of the heating tube body (41); Wherein, the medium exchange port (12) of the upper joint (1) is used for connecting to the oil pipe (100); The Tesla valve (63) can prevent liquid from flowing from the hot gas outlet (21) of the lower joint (2) into the interior of the heating pipe body (41), but can allow the gas in the heating pipe body (41) to pass through and enter the well; The heating component (62) is used to heat the gas flowing therethrough.

2. The underground electric heating device according to claim 1, characterized in that: It also comprises a ferrule (61), wherein the ferrule (61) is sealed at the opening of the wiring hole (11) of the upper connector (1).

3. The underground electric heating device according to claim 2, characterized in that: The heating component (62) comprises a heating rod (621), the top end of the heating rod (621) is provided with a terminal head (620), the center of the ferrule (61) is provided with a cable hole, a cable (60) is passed through the cable hole of the ferrule (61), and the cable (60) is connected to the terminal head (620) of the heating rod (621).

4. The underground electric heating device according to claim 3, characterized in that: The heating rod (621) is sequentially covered with a plurality of groups of mutually parallel spiral baffles (622) from top to bottom.

5. The underground electric heating device according to claim 1, characterized in that: A first temperature sensor (81) and a second temperature sensor (82) are respectively provided at the air outlet and the air inlet of the heating tube body (41); The first temperature sensor (81) and the second temperature sensor (82) are provided with a display, and the display is connected to the first temperature sensor (81) and the second temperature sensor (82) respectively via a first signal line and a second signal line.

6. The underground electric heating device according to claim 5, characterized in that: The ferrule (61) is also provided with a first signal wire tube hole and a second signal wire tube hole, wherein the first signal wire tube hole and the second signal wire tube hole are respectively located on two sides of the cable wiring hole; The first signal line tube hole and the second signal line tube hole are respectively provided with a first signal line tube (71) and a second signal line tube (72), and the bottom ends of the first signal line tube (71) and the second signal line tube (72) respectively extend into the air outlet and the air inlet of the heating tube body (41); A first temperature sensor (81) and a second temperature sensor (82) are respectively disposed at the bottom ends of the first signal line tube (71) and the second signal line tube (72); A first signal line and a second signal line are respectively passed through the first signal line tube (71) and the second signal line tube (72); the bottom ends of the first signal line and the second signal line are respectively connected to a first temperature sensor (81) and a second temperature sensor (82); the top ends of the first signal line and the second signal line respectively extend upwards out of the first signal line tube (71) and the second signal line tube (72) and the line ends are exposed; The exposed ends of the first signal line tube (71) and the second signal line tube (72) are respectively connected to the display; The first temperature sensor (81) and the second temperature sensor (82) are respectively used to test the temperatures of the air outlet and the air inlet of the heating tube body (41) in real time; The display is used to display the temperatures detected by the first temperature sensor (81) and the second temperature sensor (82) in real time.

7. The underground electric heating device according to claim 1, characterized in that: The wiring hole (11) of the upper joint (1) is butt-jointed with the top end of the heating tube body (41) via a left short-circuit (31), and the bottom end of the heating tube body (41) is butt-jointed with the hot air outlet (21) of the lower joint (2); The medium exchange port (12) of the upper joint (1) is butt-jointed with the top end of the liquid discharge tube body (42) via a right short-circuit (32), and the bottom end of the liquid discharge tube body (42) is butt-jointed with the fluid medium inlet (22) of the lower joint (2).

8. The underground electric heating device according to claim 1, characterized in that: The heating tube body (41) comprises a heating tube body upper part (411) and a heating tube body lower part (412), and the bottom end of the heating tube body upper part (411) and the top end of the heating tube body lower part (412) are connected together by threads; The heating component (62) is arranged on the upper part (411) of the heating tube body; The Tesla valve (63) is arranged at the lower part (412) of the heating tube body.

9. A method for using the downhole electric heating device integrating convection heating and in-situ drainage according to any one of claims 1 to 8, characterized in that: include: When the liquid is discharged in situ, after the liquid at the bottom of the well reaches the hot gas outlet (21) of the lower joint (2), it will be blocked by the Tesla valve (63) and can only pass through the fluid medium inlet (22) of the lower joint (2), pass upward through the one-way valve (5), enter the liquid discharge pipe body (42), continue to move upward, enter the oil pipe (100) through the medium exchange port (12) of the upper joint (1), and finally be discharged to the ground through the oil pipe (100); When in-situ gas injection heating is required, normal temperature gas is injected into the medium exchange port (12) of the upper joint (1) through the oil pipe (100), and a portion of the gas moves downward to the bottom end of the drainage pipe body (42) and the joint with the fluid medium inlet (22) of the lower joint (2), and is blocked by the one-way valve (5); the remaining gas enters the heating pipe body (41) connected to the upper joint (1) through the transverse channel (10), is heated by the heating component (62), and becomes high temperature gas; After the high-temperature gas passes through the Tesla valve (63), it passes through the hot gas outlet (21) of the lower joint (2) and finally reaches the well.

10. The method according to claim 9, characterized in that During the process of injecting gas into the bottom of the well for heating, the first temperature sensor (81) and the second temperature sensor (82) respectively test the temperatures of the gas outlet and the gas inlet of the heating pipe body (41) in real time; The display respectively displays the temperatures tested by the first temperature sensor (81) and the second temperature sensor (82) in real time.

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