Middle-deep layer terrestrial heat efficient development device

Abstract

The invention discloses a middle-deep layer geothermal efficient development device which comprises a main well and further comprises a heat removal device arranged in the main well in the axial direction. The heat removal device comprises an outer pipe assembly and an inner pipe assembly which are coaxially arranged in a sleeved mode, and an overflowing channel is formed between the outer pipe assembly and the inner pipe assembly. The outer pipe assembly comprises an orifice pipe, an upper-section surface sleeve, a lower-section surface sleeve, a non-porous sleeve and a water filtering pipe which are coaxially communicated from top to bottom; the orifice pipe and the non-porous sleeve are arranged in a non-water-taking stratum, and the water filter pipe is arranged in a water-taking stratum; the inner pipe assembly comprises a water taking main pipe, a heat preservation pump pipe, a first heat preservation pipe, an inserting pipe, a socket pipe and a second heat preservation pipe which are sequentially and coaxially communicated from top to bottom. The submersible pump is installed in the first heat preservation pipe and is matched with the inner pipe assembly, when medium-deep layer geothermal energy is exploited in a hydrothermal mode, geothermal water does not make contact with a shallow low-temperature stratum when the deep layer geothermal energy is exploited, whole-course heat preservation in the upward flowing period is achieved, the heat exchange amount of the deep layer geothermal water and the shallow low-temperature stratum is greatly reduced, and the heat extraction power is improved.

Description

Technical Field

[0001] This invention belongs to the field of deep geothermal energy development technology, specifically relating to a high-efficiency development device for medium-deep geothermal energy. Background Technology

[0002] Medium-deep hydrothermal geothermal resources refer to geothermal resources buried at depths of 200–4000 m, with temperatures between 25–150℃. Their thermal energy is primarily utilized by extracting underground hot water. The development of medium-deep hydrothermal geothermal resources is of great significance for energy structure adjustment and the achievement of dual-carbon goals.

[0003] While the development of medium-deep hydrothermal geothermal energy is of great significance, it also faces several pressing problems. Firstly, current conventional medium-deep hydrothermal geothermal development primarily involves connecting submersible pumps to ordinary pump pipes and installing them in geothermal wells to extract geothermal water from underground reservoirs. As the submersible pumps, installed below the dynamic water level, operate, the geothermal water in the deep reservoir flows upwards through conventional steel casings to the pump chamber, continuously extracting heat. However, as the geothermal water flows upwards through the deeper reservoirs, the temperature of the surrounding formation decreases, resulting in some heat loss to the shallower formations and reducing the usable heat at the surface. Furthermore, the large cross-sectional dimensions of the steel casing below the pump chamber and the relatively slow upward flow velocity exacerbate heat loss. Secondly, the pump pipes above the submersible pumps are generally just ordinary steel pipes without insulation, resulting in significant heat loss as the geothermal water flows through the pipe section, further aggravating heat loss. Thirdly, in the current process of medium-deep hydrothermal geothermal extraction, in order to ensure the long-term stable operation of the extraction well, it is often necessary to change the extraction well into a reinjection well to ensure the long-term stable water production of the geothermal reservoir. This requires the ability to flexibly switch between extraction and reinjection conditions within the same well, reducing the number of pumping operations and saving costs.

[0004] Furthermore, in the early stages of medium-deep geothermal exploration and development, exploratory wells are often constructed with the aim of hydrothermal extraction. However, if the well reaches the designed depth but there is no water or very little water, the risk of the well becoming abandoned increases. If this risk had been considered in the initial design, the well could have been converted to extract hot dry rock, thus revitalizing the exploratory well and reducing losses. Summary of the Invention

[0005] In view of the defects and deficiencies in the existing technology, the present invention provides a medium-deep geothermal high-efficiency development device to solve the technical problem of large heat loss in deep hydrothermal geothermal development in the existing technology.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A high-efficiency development device for medium-deep geothermal energy includes a main well and a heat extraction device arranged axially within the main well. The heat extraction device includes an outer tube assembly and an inner tube assembly coaxially sleeved together, and a flow channel is formed between the outer tube assembly and the inner tube assembly; The outer tube assembly includes an orifice tube, an upper surface sleeve, a lower surface sleeve, a non-perforated sleeve, and a filter tube, all coaxially connected from top to bottom. The orifice pipe and the non-perforated sleeve are installed in the non-water intake stratum, and the filter pipe is installed in the water intake stratum. The inner pipe assembly includes a water intake main pipe, a heat-insulating pump pipe, a first heat-insulating pipe, a spigot pipe, a socket pipe, and a second heat-insulating pipe, which are coaxially connected from top to bottom.

[0007] The present invention also has the following technical features: Specifically, the upper end of the second insulation pipe is fitted with a first connecting unit. The first connecting unit includes an insulation pipe hanger and a hanging base connected from top to bottom. The insulation pipe hanger includes an integrally connected connecting section and a fixing section. The connecting section extends into the socket pipe. The hanging base is connected to the upper surface sleeve.

[0008] Furthermore, a water passage hole is provided axially through the fixed section.

[0009] Furthermore, a second connecting unit is fitted on the upper outer side of the non-perforated sleeve. The second connecting unit includes a sleeve hanger and a sleeve suspension base connected from top to bottom. The lower end of the lower surface sleeve is connected to the sleeve suspension base, and the upper end of the non-perforated sleeve extends into the sleeve hanger.

[0010] Furthermore, the upper end of the orifice pipe is provided with a return port, and a return pipe is connected to the return port, and a return valve is provided on the return pipe.

[0011] Furthermore, the upper end of the socket tube is provided with an upper conical opening, and the insertion tube extends into the socket tube through the upper conical opening.

[0012] Furthermore, the upper end of the first insulation pipe is provided with an upper insulation pipe flange and an insulation pipe sealing flange, the lower end of the first insulation pipe is provided with a lower insulation pipe flange, the upper end of the insertion pipe is provided with an insertion pipe flange, and the lower insulation pipe flange is connected to the insertion pipe flange.

[0013] Furthermore, the suspension base is mounted on the main shaft wall.

[0014] Furthermore, a submersible pump is connected to the bottom end of the heat-insulating pump pipe.

[0015] Compared with the prior art, the present invention has the following technical effects: (1) The medium-deep geothermal high-efficiency development device provided by the present invention designs and installs the submersible pump inside the first insulation pipe. With the help of the inner pipe assembly, the geothermal water does not come into contact with the shallow low-temperature stratum during deep geothermal extraction, while ensuring the insulation of the entire process during the upstream flow. This greatly reduces the heat exchange between the deep geothermal water and the shallow low-temperature stratum, thereby significantly improving the heat extraction power under the same working conditions.

[0016] (2) By combining the control of the water intake valve, the reinjection valve and the heat-insulating pipe hanger with water passage hole, the flexible switching between water intake and reinjection can be realized, which broadens the function of the same geothermal well, greatly improves the utilization rate of geothermal well, and reduces the risk of reinjection layer blockage and the cost of handling and maintenance in geothermal well.

[0017] (3) With the help of the device of the present invention, when the exploration well constructed for the purpose of hydrothermal mining is dry or has very little water, the source-side circulating water pump placed below the groundwater level in the geothermal well can be used to realize the smooth conversion from hydrothermal to heat exchange mining without increasing the transformation cost, thus ensuring the successful implementation of deep geothermal mining in heat exchange mining. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a partial structural schematic diagram I of the present invention; Figure 3 This is a partial structural schematic diagram II of the present invention; The labels in the diagram represent: 1-Outer pipe assembly, 2-Inner pipe assembly, 3-Non-water intake formation, 4-Water intake formation, 5-First connecting unit, 6-Second connecting unit, 7-Reinjection pipe, 8-Reinjection valve, 9-Submersible pump; 11-Orifice pipe, 12-Upper surface sleeve, 13-Lower surface sleeve, 14-Non-perforated sleeve, 15-Filter pipe; 21-Water intake main pipe, 22-Insulated pump pipe, 23-First insulated pipe, 24-Spindle pipe, 25-Socket pipe, 26-Second insulated pipe, 27-Upper flange of insulated pipe, 28-Sealing flange of insulated pipe, 29-Lower flange of insulated pipe, 210-Spindle pipe flange, 211-Water intake valve; 51-Insulated pipe hanger, 52-Hanging base; 511-Connecting section, 512-Fixing section; 61-Casing hanger, 62-Casing hanging base; 5113-Through hole. Detailed Implementation

[0019] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0020] When describing the orientation in this invention, it is important to understand that... Figure 1 The directions shown are described, and the terms "up," "down," "front," "back," "left," "right," etc., indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0022] Unless otherwise specified, all components in this invention are commercially available.

[0023] Example Following the above technical solution, such as Figures 1 to 3 As shown, this embodiment provides a medium-deep geothermal high-efficiency development device, including a main well and a heat extraction device arranged axially within the main well; The heat extraction device includes an outer tube assembly 1 and an inner tube assembly 2 coaxially sleeved together, with a flow channel formed between the outer tube assembly 1 and the inner tube assembly 2; the outer tube assembly 1 undertakes the functions of well wall support, formation isolation and fluid introduction: including separating the non-water-producing formation from the interior, ensuring well stability, and introducing water from the water-producing formation into the device.

[0024] The outer tube assembly 1 includes an orifice tube 11, an upper surface sleeve 12, a lower surface sleeve 13, a non-perforated sleeve 14, and a filter tube 15, which are coaxially connected from top to bottom. Among them, the upper surface casing 12 and the lower surface casing 13 serve as the main pressure-bearing and structural support components, penetrating the non-water intake formation 3 to prevent well wall collapse and provide anchoring foundations for the inner casing assembly and connection unit; the non-perforated casing 14 is installed in the non-water intake formation 3 and its function is to seal and isolate; the filter pipe 15 is used for filtration and water intake.

[0025] The orifice pipe 11 and the non-perforated casing 14 are installed in the non-water intake formation 3, and the filter pipe 15 is installed in the water intake formation 4. The surface of the filter pipe 15 is formed with water holes by a perforation and wire winding process. During the water intake process, the large-diameter impurities in the formation can be filtered out. A water stop umbrella is installed on the outside of the connection between the non-perforated casing 14 and the filter pipe 15 to prevent cement from returning to the non-water intake formation and blocking the water intake layer during the cementing process.

[0026] The inner pipe assembly 2 includes a water intake main pipe 21, a heat-insulating pump pipe 22, a first heat-insulating pipe 23, a plug pipe 24, a socket pipe 25, and a second heat-insulating pipe 26, which are coaxially connected from top to bottom. Preferably, the second heat-insulating pipe 26 is a vacuum tube with a thermal conductivity of less than 0.02 W / m·K.

[0027] The inner pipe assembly 2 forms a dedicated lifting and insulation channel for high-temperature geothermal fluid, which will quickly transport the geothermal-heated fluid at the bottom of the well to the surface with minimal heat loss.

[0028] Among them, the water intake main pipe 21 is the final channel for the high-temperature fluid to flow out of the wellhead; the hot water upward insulation channel composed of the insulation pump pipe 22, the first insulation pipe 23, the insertion pipe 24, the socket pipe 25, and the second insulation pipe 26 greatly increases the water temperature at the surface water outlet.

[0029] As a preferred embodiment of this invention, such as Figure 2 As shown, a first connecting unit 5 is sleeved on the upper end of the second insulation pipe 26. The first connecting unit 5 includes an insulation pipe hanger 51 and a hanging base 52 connected from top to bottom. The insulation pipe hanger 51 includes an integrally connected connecting section 511 and a fixing section 512. The connecting section 511 extends into the socket pipe 25 and is threadedly connected to the socket pipe 25. The hanging base 52 is connected to the upper surface sleeve 12 (e.g., threaded connection). The inner wall of the fixing section 512 can fit snugly against the inner wall of the upper surface sleeve 12. A sealing ring is also provided between the insulation pipe hanger 51 and the hanging base 52 to ensure an annular seal between the insulation pipe hanger 51 and the hanging base 52, preventing fluids from different layers from passing through this gap. The upper end of the second insulation pipe 26 extends into the fixing section 512, and the second insulation pipe 26 is threadedly connected to the fixing section 512.

[0030] As a preferred embodiment, a water passage hole 5111 is provided axially in the fixed section 512. When the water intake well is switched to a reinjection well, the water passage hole 5111 can become part of the reinjection water channel.

[0031] As a preferred embodiment of this invention, such as Figure 2 As shown, a second connecting unit 6 is sleeved on the upper outer side of the non-perforated sleeve 14. The second connecting unit 6 includes a sleeve hanger 61 and a sleeve suspension base 62 connected from top to bottom. The lower end of the lower surface sleeve 13 is connected to the sleeve suspension base 62 (e.g., by threaded connection). The upper end of the non-perforated sleeve 14 extends into the sleeve hanger 61, and the non-perforated sleeve 14 can be threadedly connected to the sleeve hanger 61.

[0032] As a preferred embodiment, the upper end of the orifice pipe 11 is provided with a return port, the return port is connected to a return pipe 7, and the return pipe is provided with a return valve 8.

[0033] As a preferred embodiment of this invention, such as Figure 3 As shown, the upper end of the socket tube 25 is provided with an upper conical opening, and the insertion tube 24 extends into the socket tube 25 through the upper conical opening. The insertion tube 24 and the socket tube can be connected by threads. The upper conical opening is made into a flared shape to facilitate the insertion and connection of the insertion tube 24, and the length can be flexibly adjusted to ensure an effective connection. The insertion tube 24 and the socket tube 25 are preferably insulated tubes.

[0034] As a preferred embodiment, the upper end of the first insulation pipe 23 is provided with an upper insulation pipe flange 27 and an insulation pipe sealing flange 28, the lower end of the first insulation pipe 23 is provided with a lower insulation pipe flange 29, the upper end of the insertion pipe 24 is provided with an insertion pipe flange 210, and the lower insulation pipe flange 29 is connected to the insertion pipe flange 210.

[0035] As a preferred embodiment, the suspension base 52 is mounted on the main shaft wall.

[0036] In a preferred embodiment, the bottom end of the insulated pump pipe 22 is connected to a submersible pump 9, which is immersed in the fluid flowing into the area of ​​the filter pipe 15. The suction end directly extracts the geothermal water from that location. This allows for geothermal extraction using hydrothermal methods when water is abundant, as well as heat exchange methods when there is no water or very little water.

[0037] Specifically, the function of submersible pump 9 is to provide the upward power of geothermal water, pumping the hot water flowing from the intake layer into the inner pipe assembly, overcoming head loss and frictional resistance, and driving the entire system to circulate.

[0038] The use of this invention includes: when taking water, closing the reinjection valve 8 to control the system pressure; under the action of the submersible pump 9, the hot water flowing into the water intake layer enters the water intake main pipe 21 through the inner pipe assembly and can eventually flow out; When reinjection is required (reinjecting the used low-temperature water back into the formation), the reinjection valve 8 is opened, and the fluid can be reinjected through the flow channel between the outer pipe assembly 1 and the inner pipe assembly 2, and then returned to the formation through the filter pipe. This realizes the integrated design of heat extraction and reinjection, which is conducive to the sustainable development of geothermal resources.

[0039] When it is necessary to change to a heat exchange method for geothermal extraction, the submersible pump 9 is installed below the possible water level, the reinjection valve 8 is opened, and the fluid can be reinjected into the well through the flow passage between the outer pipe assembly 1 and the inner pipe assembly 2. The submersible pump 9 is used to draw circulating fluid to the energy station, and the flow rate drawn is the same as that of the reinjected fluid. This achieves a smooth transition from hydrothermal to heat exchange extraction without increasing the cost of geothermal well modification, and ensures the successful implementation of deep geothermal extraction in the heat exchange method.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-efficiency development device for medium-deep geothermal resources, comprising a main well, characterized in that, It also includes a heat extraction device arranged axially within the main well; The heat extraction device includes an outer tube assembly (1) and an inner tube assembly (2) coaxially sleeved together, and a flow channel is formed between the outer tube assembly (1) and the inner tube assembly (2); The outer pipe assembly (1) includes an orifice pipe (11) coaxially connected from top to bottom, an upper surface sleeve (12), a lower surface sleeve (13), a non-perforated sleeve (14), and a filter pipe (15). The orifice pipe (11) and the non-perforated sleeve (14) are installed in the non-water intake stratum (3), and the filter pipe (15) is installed in the water intake stratum (4); The inner pipe assembly (2) includes a water intake main pipe (21), a heat-insulating pump pipe (22), a first heat-insulating pipe (23), a plug pipe (24), a socket pipe (25), and a second heat-insulating pipe (26) arranged coaxially from top to bottom.

2. The high-efficiency development device for medium-deep geothermal energy as described in claim 1, characterized in that, The upper end of the second insulation pipe (26) is fitted with a first connecting unit (5). The first connecting unit (5) includes an insulation pipe hanger (51) and a hanging base (52) connected from top to bottom. The insulation pipe hanger (51) includes an integrally connected connecting section (511) and a fixed section (512). The connecting section (511) extends into the socket pipe (25). The fixed hanging base (52) is connected to the upper surface sleeve (12).

3. The high-efficiency development device for medium-deep geothermal energy as described in claim 2, characterized in that, A water passage hole (5111) is provided axially through the fixed section (512).

4. The high-efficiency development device for medium-deep geothermal energy as described in claim 1, characterized in that, The upper end of the non-perforated sleeve (14) is fitted with a second connecting unit (6). The second connecting unit (6) includes a sleeve hanger (61) and a sleeve suspension base (62) connected from top to bottom. The lower end of the lower surface sleeve (13) is connected to the sleeve suspension base (62), and the upper end of the non-perforated sleeve (14) extends into the sleeve hanger (61).

5. The high-efficiency development device for medium-deep geothermal energy as described in claim 1, characterized in that, The upper end of the orifice pipe (11) is provided with a return port, and a return pipe (7) is connected to the return port. A return valve (8) is provided on the return pipe.

6. The high-efficiency development device for medium-deep geothermal energy as described in claim 1, characterized in that, The upper end of the socket tube (25) is provided with an upper conical opening, and the insertion tube (24) extends into the socket tube (25) through the upper conical opening.

7. The high-efficiency development device for medium-deep geothermal energy as described in claim 1, characterized in that, The first insulation pipe (23) is provided with an upper flange (27) and a sealing flange (28) at its upper end, and a lower flange (29) at its lower end. The insertion pipe (24) is provided with an insertion pipe flange (210) at its upper end, and the lower flange (29) is connected to the insertion pipe flange (210).

8. The high-efficiency development device for medium-deep geothermal energy as described in claim 2, characterized in that, The suspension base (52) is installed on the main well wall.

9. The high-efficiency development device for medium-deep geothermal energy as described in claim 1, characterized in that, The bottom end of the insulated pump pipe (22) is connected to a submersible pump (9).

10. The high-efficiency development device for medium-deep geothermal energy as described in claim 1, characterized in that, A water intake valve (211) is installed on the water intake main pipe (21).

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