Closed underground heat exchange hole well body structure

Abstract

The utility model discloses a closed underground heat exchange hole well bore structure which effectively solves the problems that the heat exchange efficiency of a single circulation loop is low, and the utilization rate of heat energy in a middle-deep layer is limited. Which comprises a vertical well vertically extending downwards from the ground, and is characterized in that a heat preservation pipe is arranged in the vertical well, a packer is arranged at the bottom of the heat preservation pipe and divides the vertical well into an upper well part and a lower well part which are separated from each other, an inclined well located below the ground is arranged on one side of the vertical well, and the inclined well is arranged in the vertical well. The inclined well is divided into an inclined part and a vertical part, and one end of the inclined part is communicated with the upper well part; the second horizontal well is ingenious in structure and convenient to use, the problem that water flow among a plurality of second horizontal wells flows slowly is solved through the arrangement of the guide assembly and the like, the flowing speed of liquid media in the second horizontal wells is controlled by adjusting the positions of the guide arc pieces, meanwhile, the guide arc pieces can be adjusted according to different use requirements, and the service life of the second horizontal wells is prolonged. And adjustment of the flowing speed of liquid in the second horizontal well is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of medium-deep underground heat exchange, in particular to a closed underground heat exchange hole well body structure. Background Art

[0002] Although geothermal energy is widely accepted as an environmentally friendly and economical green energy, there are still some technical difficulties in its application. For example, under certain geological conditions, it is difficult to fully recharge geothermal water. Although the mode of multiple injections can solve the recharge problem, it seriously affects the economic efficiency of the geothermal heating system and is only a stopgap measure. The technical demand of "taking heat without taking water" has become the most concerned topic in all recent geothermal technology exchange meetings.

[0003] The technology of "taking heat without taking water" and the medium-deep closed shell-and-tube heat exchange system also have many experiments and engineering cases. The problem is that the heat exchange performance is not high, and the average stable heat exchange load is 100-250kW. This is related to the fact that the system adopts a heat exchange mode based on heat conduction, and it is also related to the fact that it simply uses the well wall for heat exchange, and the heat exchange area is small. Therefore, one of the directions for improving this technology is to develop the heat exchange process into the aquifer or formation, turning it into a heat exchange process combining convection and heat conduction, and at the same time expanding the heat exchange area.

[0004] The Chinese utility model patent application No. 201922468295.6 discloses a medium-deep single-hole butt-joint heat exchange type geothermal well body structure, which includes a vertical well buried underground, a first horizontal well and a second horizontal well that form a circulation loop with the vertical well. Low-temperature water enters the well, flows downward from the annular space between the insulation pipe and the vertical well, passes through the first horizontal well, the cement body and the second horizontal well, rises to the surface along the insulation pipe and enters the heat source side of the heat pump, and returns to the annular space between the insulation pipe and the vertical well after exiting the heat source side of the heat pump. The low-temperature water that has released heat from the heat source side of the heat pump passes through the high-temperature well section and undergoes heat exchange and increases in temperature before entering the heat source side of the heat pump. The reciprocating cycle continuously delivers energy to the heat pump, achieving the purpose of extracting heat without extracting water. The medium-deep single-hole butt-joint heat exchange type geothermal well body structure has a low efficiency of heat exchange through a single circulation loop, and has limited utilization of thermal energy in the medium-deep layer. Utility Model Content

[0005] In view of the above situation, in order to overcome the defects of the prior art, the purpose of the present utility model is to provide a closed downhole heat exchange hole wellbore structure, which effectively solves the problems mentioned in the background technology.

[0006] The technical solution is that the utility model comprises a vertical well extending vertically downward from the ground, characterized in that a heat preservation pipe is arranged in the vertical well, a packer is arranged at the bottom of the heat preservation pipe, and the packer separates the vertical well into an upper well portion and a lower well portion which are isolated from each other;

[0007] A slanted well located below the ground is provided on one side of the vertical well, the slanted well is divided into a slanted part and a vertical part, one end of the slanted part is connected to the upper well part, a first horizontal well is provided below the slanted well on one side of the vertical well, one end of the first horizontal well close to the vertical well is connected to the lower well part, and one end of the first horizontal well far from the vertical well is connected to the vertical part;

[0008] A plurality of second horizontal wells are arranged between the inclined well and the first horizontal well, the two ends of the second horizontal wells are respectively connected with the lower well portion and the vertical portion, a guide assembly is fixed inside the second horizontal well, and the guide assembly is located at the connection between the second horizontal well and the vertical portion;

[0009] The guide assembly includes a guide cylinder fixed on the inner wall of the second horizontal well, a guide arc piece is coaxially slidable inside the guide cylinder, and the guide arc piece is divided into a horizontal sliding part and an arc-shaped guide part, and the arc-shaped guide part is located in the vertical part.

[0010] Preferably, sliding grooves are provided on both sides of the inner wall of the guide cylinder, a plurality of one-way teeth are arranged inside the sliding grooves, two through grooves are provided on the outer wall of the guide arc piece, the through grooves correspond to the sliding grooves one by one, a rotating rod is fixed inside the through groove, a top plate is rotatably connected to the rotating rod, the inner side surface of the top plate is connected to the through groove by a spring, and one end of the top plate is engaged with the one-way teeth.

[0011] Preferably, a plurality of reinforcing ribs are distributed circumferentially on the inner wall of the guide arc piece.

[0012] Preferably, a limiting groove is provided on the inner wall of the guide cylinder, a limiting block is fixed on the outer wall of the guide arc piece, and the limiting block is clamped in the limiting groove.

[0013] Preferably, a mounting ring is fixed on the guide cylinder.

[0014] Preferably, the engaging end between the top plate and the one-way tooth is arranged in a circular arc.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] 1. Through the setting of multiple second horizontal wells, inclined wells and first horizontal wells, the thermal energy utilization of multiple circulation loops is realized, which is less restricted by the site, has high heating capacity and improves the versatility of the overall heat exchange well system.

[0017] 2. The problem of slow water flow between multiple second horizontal wells is solved by setting guide components and the like. The flow rate of the liquid medium inside the second horizontal well is controlled by adjusting the position of the guide arc piece. The overall device has a simple structure and is easy to install. At the same time, the guide arc piece can be adjusted according to different usage requirements to achieve the adjustment of the liquid flow rate in the second horizontal well. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a plan view of the utility model.

[0019] Figure 2 It is a structural schematic diagram of the guide component in the utility model.

[0020] Figure 3 It is a structural schematic diagram of the guide tube in the utility model.

[0021] Figure 4 It is a structural schematic diagram of the guide arc piece in the utility model.

[0022] Figure 5 This utility model Figure 4 A schematic diagram of the enlarged structure at point A in the middle.

[0023] Figure 6 It is a cross-sectional view of the guide assembly in the utility model.

[0024] Figure 7 This utility model Figure 6 A magnified schematic diagram of the structure at point B in the middle.

[0025] Explanation of the symbols in the schematic diagram:

[0026] 10. Vertical well; 101. Upper wellhead; 102. Lower wellhead; 20. Insulation pipe; 30. Packer; 40. Inclined well; 401. Inclined part; 402. Vertical part; 50. Second horizontal well; 60. First horizontal well; 70. Guide cylinder; 701. Mounting ring; 702. Slide groove; 703. Limiting groove; 704. One-way tooth; 71. Guide arc piece; 711. Reinforcement rib; 712. Limiting block; 713. Through groove; 714. Rotating rod; 72. Top plate. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] Depend on Figure 1 to Figure 2A vertical well 10 extending vertically downward from the ground is provided, wherein a heat preservation pipe 20 is provided in the vertical well 10, and a packer 30 is provided at the bottom of the heat preservation pipe 20, wherein the packer 30 separates the vertical well 10 into an upper well portion 101 and a lower well portion 102 which are separated from each other, and the packer 30 is made of rubber material, which swells when exposed to water, thereby separating the straight pipe and preventing water in the upper well portion 101 from entering the lower well portion 102;

[0029] Further, considering that the heat exchange efficiency of the traditional unidirectional vertical well 10 is low, in order to enhance the heat exchange efficiency at the same buried depth, a slanted well 40 located below the ground is provided on one side of the vertical well 10, and the slanted well 40 is divided into a slanted portion 401 and a vertical portion 402, one end of the slanted portion 401 is connected to the upper well portion 101, and a first horizontal well 60 located below the slanted well 40 is provided on one side of the vertical well 10, and one end of the first horizontal well 60 close to the vertical well 10 is connected to the lower well portion 102, and one end of the first horizontal well 60 away from the vertical well 10 is connected to the vertical portion 402, at this time, a circulation loop is formed between the first horizontal well 60, the vertical well 10 and the slanted well 40, and such a setting can correspondingly improve the heat exchange efficiency, but the disadvantage is also obvious, and the utilization rate of geothermal heat in the middle and deep layers cannot be optimized by a circulation loop;

[0030] Further, in order to solve the use defects of the above-mentioned one circulation loop, a plurality of second horizontal wells 50 are arranged between the inclined well 40 and the first horizontal well 60, and the two ends of the second horizontal well 50 are respectively connected with the lower well portion 102 and the vertical portion 402, and a guide assembly is fixed inside the second horizontal well 50, and the guide assembly is located at the connection between the second horizontal well 50 and the vertical portion 402. On the basis of one circulation loop, a plurality of second horizontal wells 50 are added, and the number of second horizontal wells 50 is adjusted according to actual use needs, and one circulation loop is changed into a plurality of circulation loops, which greatly enhances the heat exchange efficiency within the depth range of the middle and deep layers. However, problems with the plurality of circulation loops are also found during use, and the water flow inside the plurality of second horizontal wells 50 is stagnant or the liquid flows slowly, and the coordination degree of the plurality of circulation loops is not high;

[0031] Furthermore, in order to solve the problem of low coordination among the above-mentioned multiple circulation loops, the guide assembly includes a guide cylinder 70 fixed on the inner wall of the second horizontal well 50, and a guide arc plate 71 is coaxially slid inside the guide cylinder 70. The guide arc plate 71 is divided into a horizontal sliding portion and an arc-shaped guide portion, and the arc-shaped guide portion is located in the vertical portion 402. By arranging a guide cylinder 70 and a guide arc plate 71 inside each second horizontal well 50, the arc-shaped guide portion of the guide arc plate 71 is placed in the vertical portion 402. When the liquid inside the vertical portion 402 circulates from top to bottom, a part of the liquid is guided into the second horizontal well 50, so as to push the liquid inside the second horizontal well 50, thereby accelerating the flow rate of the liquid and improving the coordination among the multiple circulation loops.

[0032] refer to Figures 3 to 7 As shown, considering that different usage requirements have different extension amounts of the guide arc piece 71, both sides of the inner wall of the guide cylinder 70 are provided with slide grooves 702, and a plurality of one-way teeth 704 are arranged inside the slide grooves 702. Two through grooves 713 are provided on the outer wall of the guide arc piece 71, and the through grooves 713 correspond to the slide grooves 702 one by one. A rotating rod 714 is fixed inside the through groove 713, and a top plate 72 is rotatably connected to the rotating rod 714. The inner side surface of the top plate 72 is connected to the through groove 713 by a spring. 2 is engaged with the one-way tooth 704, and through the arrangement of the slide groove 702, the one-way tooth 704 and the top plate 72, before installing the guide assembly, the extension amount of the guide arc piece 71 is first adjusted. At the same time, in order to avoid the guide arc piece 71 from retracting in the vertical portion 402, the top plate 72 and the one-way tooth 704 are supported by each other. In summary, the extension amount of the guide arc piece 71 can be adjusted according to different usage requirements, and the water flow velocity inside the second horizontal well 50 also changes accordingly, and the guide arc piece 71 can also be prevented from retracting.

[0033] refer to Figure 4 As shown, in order to meet the supporting strength of the guide arc piece 71, a plurality of reinforcing ribs 711 are distributed circumferentially on the inner wall of the guide arc piece 71. The arrangement of the plurality of reinforcing ribs 711 can not only meet the supporting strength of the guide arc piece 71, but also the guide grooves formed between the reinforcing ribs 711 can enhance the drainage effect of the liquid.

[0034] refer to Figure 3 and Figure 4 As shown, in order to prevent the guide arc piece 71 from rotationally offset, a limiting groove 703 is opened on the inner wall of the guide cylinder 70, and a limiting block 712 is fixed on the outer wall of the guide arc piece 71. The limiting block 712 is clamped in the limiting groove 703, and the guide arc piece 71 is limited by the above-mentioned limiting block 712 and the limiting groove 703.

[0035] refer to Figure 2 and Figure 3 As shown, a mounting ring 701 is fixed on the guide tube 70 , and the mounting ring 701 is convenient for installation on the inner wall of the second horizontal well 50 .

[0036] refer to Figure 7 As shown, when adjusting the guide arc piece 71, obstruction is prevented between the top plate 72 and the one-way tooth 704. The clamping ends of the top plate 72 and the one-way tooth 704 are set as arcs to avoid affecting the adjustment of the guide arc piece 71 due to the thickness of the top plate 72.

[0037] When the utility model is used:

[0038] First, the vertical well 10 part, the inclined well 40 part, the first horizontal well 60 part and the second horizontal well 50 parts are constructed respectively. During the construction process, it is necessary to pay attention to the deflection treatment at the turning point, and the oil casing is set in each part;

[0039] Then, when the oil casing of the second horizontal well 50 is installed, the guide assembly is installed on the inner wall of the second horizontal well 50, and the whole well section is cemented, thereby completing the connection of multiple circulation loops;

[0040] Secondly, before installing the guide assembly, the extension amount of the guide arc piece 71 is adjusted according to different usage requirements. During the adjustment process, the guide arc piece 71 is directly pushed to move to the specified position, and the top plate 72 is engaged with the corresponding one-way tooth 704;

[0041] Finally, the flow direction of the heat exchange medium in the multiple circulation loops is as follows: the liquid in the upper well portion 101 enters from the inclined well 40 , converges to the lower well portion 102 in the multiple circulation loops formed by the first horizontal well 60 and the multiple second horizontal wells 50 , and flows out.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A closed downhole heat exchange hole wellbore structure, comprising a vertical well (10) extending vertically downward from the ground, characterized in that: A heat preservation pipe (20) is arranged in the vertical well (10), a packer (30) is arranged at the bottom of the heat preservation pipe (20), and the packer (30) separates the vertical well (10) into an upper well portion (101) and a lower well portion (102) which are isolated from each other; A slanted well (40) located below the ground is provided on one side of the vertical well (10), the slanted well (40) is divided into a slanted portion (401) and a vertical portion (402), one end of the slanted portion (401) is connected to an upper well portion (101), a first horizontal well (60) located below the slanted well (40) is provided on one side of the vertical well (10), an end of the first horizontal well (60) close to the vertical well (10) is connected to the lower well portion (102), and an end of the first horizontal well (60) far from the vertical well (10) is connected to the vertical portion (402); A plurality of second horizontal wells (50) are arranged between the inclined well (40) and the first horizontal well (60), and two ends of the second horizontal well (50) are respectively connected to the lower well portion (102) and the vertical portion (402), and a guide assembly is fixed inside the second horizontal well (50), and the guide assembly is located at the connection between the second horizontal well (50) and the vertical portion (402); The guide assembly comprises a guide tube (70) fixed on the inner wall of the second horizontal well (50), a guide arc plate (71) is coaxially slidable inside the guide tube (70), and the guide arc plate (71) is divided into a horizontal sliding part and an arc-shaped guide part, and the arc-shaped guide part is located in the vertical part (402).

2. A closed downhole heat exchange hole wellbore structure according to claim 1, characterized in that: Slide grooves (702) are provided on both sides of the inner wall of the guide cylinder (70), and a plurality of one-way teeth (704) are arranged inside the slide groove (702). Two through grooves (713) are provided on the outer wall of the guide arc plate (71), and the through grooves (713) correspond to the slide grooves (702) one by one. A rotating rod (714) is fixed inside the through groove (713), and a top plate (72) is rotatably connected to the rotating rod (714). The inner side surface of the top plate (72) is connected to the through groove (713) by a spring, and one end of the top plate (72) is clamped with the one-way teeth (704).

3. A closed downhole heat exchange hole wellbore structure according to claim 1, characterized in that: A plurality of reinforcing ribs (711) are distributed circumferentially on the inner wall of the guide arc piece (71).

4. A closed downhole heat exchange hole wellbore structure according to claim 1, characterized in that: A limiting groove (703) is provided on the inner wall of the guide cylinder (70), a limiting block (712) is fixed on the outer wall of the guide arc piece (71), and the limiting block (712) is clamped in the limiting groove (703).

5. The closed downhole heat exchange hole wellbore structure according to claim 1, characterized in that: A mounting ring (701) is fixed on the guide cylinder (70).

6. A closed downhole heat exchange hole wellbore structure according to claim 2, characterized in that: The clamping ends of the top plate (72) and the one-way teeth (704) are arranged in an arc shape.

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