A dry hot rock single well double horizontal artificial fracturing heat exchange method

Abstract

The application discloses a dry hot rock single-well double-horizontal artificial fracturing heat exchange method and belongs to the technical field of dry hot rock development. According to the method, after the heat exchange medium is introduced into the cooling through sleeve, the cooling mechanism is driven to drive the refrigeration device to refrigerate, cold air is diffused to all parts of the cooling through sleeve, the heat exchange medium is dispersed into several small heat exchange media by the first dispersion net and the second dispersion net, the heat exchange medium is cooled comprehensively, the water cooling temperature reduction mechanism absorbs heat by dissolving potassium nitrate powder in the water solution, the air cooling temperature reduction mechanism absorbs heat by decomposing ammonium chloride powder into hydrogen chloride and ammonia gas, the residual heat of the heat exchange medium is fully absorbed, the temperature of the heat exchange medium and the cooling through sleeve is reduced, the cold quantity in the cooling through sleeve is transferred to the heat exchange medium, the residual heat in the heat exchange medium is rapidly radiated and absorbed, the heat exchange medium is fully cooled, the cooling and temperature reduction of the heat exchange medium are more rapid and comprehensive, the cooling effect is enhanced, and the heat exchange medium is conveniently recycled.

Description

Technical Field

[0001] This invention relates to the field of hot dry rock development technology, and more specifically, to a method for artificial fracturing and heat exchange in a single well in hot dry rock. Background Technology

[0002] Hot dry rock generally refers to high-temperature rock masses with temperatures ranging from 150 to 550°C, buried at depths of several thousand meters, and containing little or no underground fluid. The key technology for developing hot dry rock is the fracturing and extraction of the rock mass. The purpose of fracturing hot dry rock is to increase its permeability, allowing the "underground heat exchanger" to have a larger heat exchange area. Currently, the main use of hot dry rock for development is power generation.

[0003] Currently, there are two main categories of heat exchange methods for hot dry rock: single-well circulation heat exchange and dual-well circulation heat exchange. Single-well heat exchange is low-cost and energy-saving, but its heat exchange effect is poor and its thermal energy utilization rate is low. Furthermore, the single-well circulation heat exchange method for hot dry rock requires cooling of the heat exchange medium to ensure its circulation heat exchange. However, the existing cooling devices have low cooling efficiency and poor performance. Summary of the Invention

[0004] 1. Technical problems to be solved

[0005] To address the problems existing in the prior art, the present invention aims to provide a method for artificial fracturing heat exchange in a single well of hot dry rock. This method involves introducing the heat exchange medium into the cooling cylinder, driving a cooling mechanism to activate a refrigeration device, dispersing cold air throughout the cooling cylinder. Combined with a first and second dispersing net, the heat exchange medium is dispersed into several smaller streams for comprehensive cooling. Furthermore, a water-cooling mechanism absorbs heat by dissolving potassium nitrate powder in an aqueous solution, while an air-cooling mechanism absorbs heat by decomposing ammonium chloride powder into hydrogen chloride and ammonia gas. This ensures that the residual heat emitted by the heat exchange medium is fully absorbed, reducing its temperature and that of the cooling cylinder. This facilitates the transfer of cold energy from inside the cooling cylinder to the heat exchange medium, rapidly dissipating and absorbing any remaining residual heat, resulting in thorough cooling. This leads to faster and more comprehensive cooling of the heat exchange medium, enhancing the cooling effect and facilitating subsequent recycling.

[0006] 2. Technical Solution

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A method for artificially fracturing heat transfer in a single well in hot dry rock includes the following steps:

[0009] S1. First, determine the burial depth of the hot dry rock, and then carry out drilling using drilling machines according to the planned drilling plan. Next, drill two horizontal wells in the same direction on the well wall.

[0010] S2. Inject cement slurry containing high thermal conductivity material into the main well and two horizontal wells of the dry hot rock, and then use supercritical carbon dioxide as the fracturing medium to form artificially fractured rock layers in the dry hot rock mass using fracturing technology.

[0011] S3. Heat exchange devices and transmission pipelines are installed inside the main dry hot rock well and two horizontal wells. Then, surface wellhead heat exchange equipment and cooling devices are installed around the wellhead to form a circulating heat exchange loop, thereby realizing the extraction of dry hot rock thermal energy.

[0012] Furthermore, the cooling device in S3 includes a cooling cylinder. Both ends of the cooling cylinder are threadedly connected to sealing circular plates. A feed pipe is fixedly connected to the left end of the sealing circular plate on the left side, and a discharge pipe is fixedly connected to the right end of the sealing circular plate on the right side. Both the feed pipe and the discharge pipe are connected to the interior of the cooling cylinder. The interior of the cooling cylinder is equipped with a driving cooling mechanism and an air-cooling mechanism. A water-cooling mechanism is also provided on the cooling cylinder. This solution achieves that after the heat exchange medium is introduced into the cooling cylinder, the driving cooling mechanism drives the refrigeration device to cool, causing the cold air to diffuse throughout the cooling cylinder, in conjunction with... The first and second dispersing nets disperse the heat exchange medium into several smaller streams, facilitating comprehensive cooling. The water-cooling mechanism absorbs heat through potassium nitrate powder dissolved in an aqueous solution, while the air-cooling mechanism absorbs heat through ammonium chloride powder decomposing into hydrogen chloride and ammonia gas. This ensures that the residual heat emitted by the heat exchange medium is fully absorbed, reducing its temperature and that of the cooling cylinder. This facilitates the transfer of cooling energy from inside the cooling cylinder to the heat exchange medium, allowing its residual heat to dissipate and be absorbed quickly, resulting in thorough cooling. This leads to faster and more comprehensive cooling of the heat exchange medium, enhancing the cooling effect and facilitating subsequent recycling.

[0013] Furthermore, the inner wall of the feed pipe is rotatably connected to two rubber seals, which are in close contact with each other. The contact and sealing of the two rubber seals can prevent the heat exchange medium from being introduced into the cooling cylinder. Under impact and extrusion, the two rubber seals rotate and open, realizing the conduction of the heat exchange medium.

[0014] Furthermore, the driving cooling mechanism includes a guide pipe embedded in the inner wall of the cooling cylinder. The inner wall of the guide pipe is fixedly connected with a first dispersion net and a second dispersion net. A refrigeration device is installed inside the cooling cylinder. The driving cooling mechanism uses the refrigeration device to cool the cylinder, causing cold air to diffuse into all parts of the guide pipe and reduce its internal temperature. The heat exchange medium is introduced into the cooling cylinder and passes through the first dispersion net and the second dispersion net in sequence, thereby being dispersed into several small heat exchange medium streams, so that the residual heat inside can be fully dissipated, facilitating comprehensive cooling.

[0015] Furthermore, both the first and second dispersion meshes are made of metallic copper. The mesh size of the first dispersion mesh is larger than that of the second dispersion mesh. By using the first and second dispersion meshes made of metallic copper, they have good thermal conductivity. After the heat exchange medium comes into contact with and disperses with them, the dissipated heat is quickly introduced into the guide tube and absorbed by the aqueous solution.

[0016] Furthermore, the water-cooling mechanism includes an annular frame fitted onto the outer end of the cooling cylinder. A flexible storage bladder is fixedly connected inside the annular frame, and the flexible storage bladder contains potassium nitrate powder. Two symmetrically positioned extrusion arc plates are fixedly connected to both ends of the flexible storage bladder. Multiple pairs of T-shaped rods are fixedly connected to the inner wall of the annular frame. Movable blocks are fitted onto each pair of T-shaped rods, and the extrusion arc plates are fixedly connected to a pair of movable blocks located on the outer side. A memory spring is fitted onto each pair of T-shaped rods, and the outer ends of the memory springs are fixedly connected to the annular frame and the movable blocks, respectively. The flexible storage bladder, the annular frame, the cooling cylinder, and the guide... A guide tube is embedded between the tubes, and the guide tube is connected to the interior of the flexible storage bladder and the guide tube respectively. A moving spray nozzle is fixedly connected to the inner wall of the guide tube. The interior of the guide tube contains an aqueous solution. After the heat exchange medium dissipates heat, it is conducted into the guide tube and absorbed by the aqueous solution. As the heat dissipates, the temperature rises. The memory spring senses the temperature rise and deforms and extends as the temperature rises. The water cooling mechanism pushes the extrusion arc plate towards the flexible storage bladder through the extension of the memory spring, extruding part of the potassium nitrate powder inside the bladder into the guide tube, where it dissolves in the aqueous solution, absorbs heat and cools down, facilitating the continuous absorption of heat.

[0017] Furthermore, a feeding tube is embedded between the flexible storage bladder and the annular frame, and the feeding tube penetrates the annular frame. The feeding tube is connected to the interior of the flexible storage bladder, and a sealing plug is interference-fitted to the feeding tube. Through the setting of the feeding tube and the sealing plug, the potassium nitrate powder can be added and used.

[0018] Furthermore, the inner wall of the movable block has two symmetrical spherical grooves, and each groove is rotatably connected with a ball bearing. The outer end of the ball bearing contacts the outer end of the T-shaped rod. The memory spring is made of shape memory alloy material. The initial state of the memory spring is a contracted state. The ball bearings make the movement of the movable block smoother and more convenient. The memory spring made of shape memory alloy material has a two-way memory effect. It deforms and extends when the temperature rises to 40°C, and returns to its initial state when the temperature drops.

[0019] Furthermore, the air-cooling mechanism includes a first built-in ring fixedly connected to the inner wall of the cooling cylinder, and a third built-in ring fixedly connected to the left end of the sealing circular plate on the right side, with the diameter of the third built-in ring matching the diameter of the discharge pipe. A second built-in ring is provided between the first and third built-in rings. A connecting frame is sequentially connected between the first, second, and third built-in rings, and the interior of the connecting frame is filled with ammonium chloride powder. The inner wall of the connecting frame is filled with a diamond powder layer. When the heat exchange medium passes through the connecting frame in the air-cooling mechanism, its residual heat is conducted to the interior of the connecting frame through the diamond powder layer. The ammonium chloride powder absorbs the heat and begins to decompose into hydrogen chloride gas and ammonia gas, fully absorbing the residual heat of the heat exchange medium, thus achieving sufficient cooling and causing its temperature to drop rapidly, enhancing the cooling effect.

[0020] 3. Beneficial effects

[0021] Compared with the prior art, the advantages of this invention are:

[0022] (1) In this scheme, after the heat exchange medium is introduced into the cooling cylinder, the cooling mechanism drives the refrigeration device to cool, so that the cold air is diffused to all parts of the cooling cylinder. With the help of the first and second dispersion nets, the heat exchange medium is dispersed into several small heat exchange mediums, which facilitates comprehensive cooling. The water cooling mechanism absorbs heat by dissolving potassium nitrate powder in the aqueous solution, and the air cooling mechanism absorbs heat by decomposing ammonium chloride powder into hydrogen chloride and ammonia gas. This allows the residual heat emitted by the heat exchange medium to be fully absorbed, reducing its temperature and that of the cooling cylinder. This promotes the transfer of cold energy inside the cooling cylinder to the heat exchange medium, allowing the residual heat inside to be quickly dissipated and absorbed, thus promoting sufficient cooling. This makes the cooling of the heat exchange medium faster and more comprehensive, enhancing the cooling effect and facilitating subsequent recycling.

[0023] (2) The inner wall of the feed pipe is rotatably connected to two rubber seals, and the two rubber seals are in close contact with each other. The contact and sealing of the two rubber seals can prevent the heat exchange medium from being introduced into the cooling tube. Under impact and extrusion, the two rubber seals rotate and open, realizing the conduction of the heat exchange medium.

[0024] (3) The driving cooling mechanism includes a guide pipe embedded in the inner wall of the cooling cylinder. The inner wall of the guide pipe is fixedly connected with a first dispersion net and a second dispersion net. A refrigeration device is installed inside the cooling cylinder. The driving cooling mechanism cools the cylinder through the refrigeration device, so that the cold air is diffused to all parts of the guide pipe, reducing its internal temperature. The heat exchange medium is introduced into the cooling cylinder and passes through the first dispersion net and the second dispersion net in sequence, thereby being dispersed into several small heat exchange media, so that the residual heat inside can be fully dissipated, facilitating comprehensive cooling.

[0025] (4) Both the first and second dispersion nets are made of copper. The mesh size of the first dispersion net is larger than that of the second dispersion net. The first and second dispersion nets made of copper have good thermal conductivity. After the heat exchange medium comes into contact with and disperses with them, the heat is quickly introduced into the guide tube and absorbed by the aqueous solution.

[0026] (5) The water-cooling mechanism includes an annular frame fitted onto the outer end of the cooling cylinder. A flexible storage bladder is fixedly connected inside the annular frame, and potassium nitrate powder is placed inside the flexible storage bladder. Two symmetrically arranged extrusion arc plates are fixedly connected to both the left and right ends of the flexible storage bladder. Multiple pairs of T-shaped rods are fixedly connected to the inner wall of the annular frame. Movable blocks are fitted on each pair of T-shaped rods, and the extrusion arc plates are fixedly connected to a pair of movable blocks located on the outer side. Memory springs are fitted on each pair of T-shaped rods, and the outer ends of the memory springs are fixedly connected to the annular frame and the movable blocks, respectively. A flexible storage bladder, annular frame, cooling cylinder, and guide pipe are embedded between them. The device is equipped with a feed tube that is connected to both the flexible storage bladder and the guide tube. A moving spray nozzle is fixedly connected to the inner wall of the feed tube. The guide tube contains an aqueous solution. After the heat exchange medium dissipates heat, it is conducted into the guide tube and absorbed by the aqueous solution. As the heat dissipates, the temperature rises. The memory spring senses the temperature rise and deforms and extends accordingly. The water-cooling mechanism pushes the extrusion plate towards the flexible storage bladder through the extension of the memory spring, extruding some of the potassium nitrate powder inside the bladder into the guide tube, where it dissolves in the aqueous solution, absorbs heat, and cools down, facilitating the continuous absorption of heat.

[0027] (6) A feeding tube is embedded between the flexible storage bladder and the annular frame, and the feeding tube passes through the annular frame. The feeding tube is connected to the interior of the flexible storage bladder. The feeding tube is interference-fitted with a sealing plug. The addition and use of potassium nitrate powder can be achieved through the setting of the feeding tube and the sealing plug.

[0028] (7) The inner wall of the movable block has two symmetrical spherical grooves, and the inside of the two spherical grooves is rotatably connected with balls. The outer end of the ball contacts the outer end of the T-shaped rod. The memory spring is made of shape memory alloy material. The initial state of the memory spring is the contracted state. The ball setting makes the movement of the movable block smoother and more convenient. The memory spring made of shape memory alloy material has a two-way memory effect. It deforms and extends after the temperature rises to 40°C, and returns to the initial state after the temperature drops.

[0029] (8) The air-cooling mechanism includes a first built-in ring fixedly connected to the inner wall of the cooling cylinder, a third built-in ring fixedly connected to the left end of the sealing circular plate on the right side, and the diameter of the third built-in ring matches the diameter of the discharge pipe. A second built-in ring is provided between the first and third built-in rings. A connecting frame is sequentially connected between the first, second, and third built-in rings. The interior of the connecting frame is provided with ammonium chloride powder, and the inner wall of the connecting frame is provided with a diamond powder layer. When the heat exchange medium passes through the connecting frame in the air-cooling mechanism, its residual heat is conducted to the interior of the connecting frame through the diamond powder layer. The ammonium chloride powder absorbs the heat and begins to decompose into hydrogen chloride gas and ammonia gas, fully absorbing the residual heat of the heat exchange medium, so that it is fully cooled, causing its temperature to drop rapidly and enhancing the cooling effect. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the cooling device in this invention;

[0031] Figure 2 This is a schematic cross-sectional view of the cooling device in this invention.

[0032] Figure 3 This is a three-dimensional structural diagram of the cooling cylinder in this invention;

[0033] Figure 4 This is a partial cross-sectional structural diagram of the water-cooling mechanism in this invention;

[0034] Figure 5 for Figure 4 Enlarged structural diagram at point A;

[0035] Figure 6 This is a three-dimensional structural diagram of the air-cooling mechanism in this invention.

[0036] Explanation of the labels in the diagram:

[0037] 100. Cooling cylinder; 200. Sealing circular plate; 300. Feed pipe; 301. Rubber sealing plate; 400. Discharge pipe; 500. Drive cooling mechanism; 501. Guide pipe; 502. First dispersing net; 503. Second dispersing net; 504. Refrigeration device; 600. Water cooling mechanism; 601. Annular frame; 602. Flexible storage bladder; 603. Feeding pipe; 604. Sealing plug; 605. T-shaped rod; 606. Movable block; 6061. Ball bearing; 607. Memory spring; 608. Extrusion arc plate; 609. Guide pipe; 6010. Motion-type spray nozzle; 700. Air cooling mechanism; 701. First built-in ring; 702. Second built-in ring; 703. Third built-in ring; 704. Connecting frame. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" 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 an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] Example:

[0042] A method for artificially fracturing heat transfer in a single well in hot dry rock includes the following steps:

[0043] S1. First, determine the burial depth of the hot dry rock, and then carry out drilling using drilling machines according to the planned drilling plan. Next, drill two horizontal wells in the same direction on the well wall.

[0044] S2. Inject cement slurry containing high thermal conductivity material into the main well and two horizontal wells of the dry hot rock, and then use supercritical carbon dioxide as the fracturing medium to form artificially fractured rock layers in the dry hot rock mass using fracturing technology.

[0045] S3. Heat exchange devices and delivery pipelines are installed inside the main dry hot rock well and two horizontal wells. Then, surface wellhead heat exchange equipment and cooling devices are installed around the wellhead to form a circulating heat exchange loop to realize the exploitation of dry hot rock thermal energy. In this scheme, supercritical carbon dioxide is used as the fracturing medium, which will form more and finer fractures inside the reservoir. The reservoir fractures have better connectivity and a larger heat exchange area, resulting in better heat exchange effect compared to water.

[0046] Please see Figure 1-6 The cooling device in S3 includes a cooling cylinder 100. Both ends of the cooling cylinder 100 are threadedly connected to sealing discs 200. The left end of the sealing disc 200 on the left side is fixedly connected to a feed pipe 300, and the right end of the sealing disc 200 on the right side is fixedly connected to a discharge pipe 400. Both the feed pipe 300 and the discharge pipe 400 are connected to the interior of the cooling cylinder 100. The interior of the cooling cylinder 100 is equipped with a driving cooling mechanism 500 and an air-cooling mechanism 700. A water-cooling mechanism 600 is installed on the cooling cylinder 100. This design achieves cooling by driving the cooling mechanism 500 to drive the refrigeration device 504 after the heat exchange medium is introduced into the cooling cylinder 100, causing the cold air to diffuse into the cooling system. The cooling cylinder 100, in conjunction with the first and second dispersing nets 502 and 503, disperses the heat exchange medium into several smaller streams for comprehensive cooling. The water-cooled cooling mechanism 600 absorbs heat by dissolving potassium nitrate powder in an aqueous solution, while the air-cooled cooling mechanism 700 absorbs heat by decomposing ammonium chloride powder into hydrogen chloride and ammonia gas. This ensures that the residual heat emitted by the heat exchange medium is fully absorbed, reducing its temperature and that of the cooling cylinder 100. This facilitates the transfer of cooling energy from inside the cooling cylinder 100 to the heat exchange medium, allowing its residual heat to dissipate and be absorbed quickly, resulting in thorough cooling. This leads to faster and more comprehensive cooling of the heat exchange medium, enhancing the cooling effect and facilitating subsequent recycling.

[0047] Please see Figure 2 The inner wall of the feed pipe 300 is rotatably connected to two rubber seals 301, and the two rubber seals 301 are in close contact with each other. The contact and sealing of the two rubber seals 301 can prevent the heat exchange medium from being introduced into the cooling cylinder 100. Under impact and extrusion, the two rubber seals 301 rotate and open, realizing the conduction of the heat exchange medium.

[0048] Please see Figure 2-3 The driving cooling mechanism 500 includes a guide pipe 501 embedded in the inner wall of the cooling cylinder 100. The inner wall of the guide pipe 501 is fixedly connected to a first dispersing net 502 and a second dispersing net 503. A refrigeration device 504 is installed inside the cooling cylinder 100. The driving cooling mechanism 500 cools the cylinder through the refrigeration device 504, causing the cold air to diffuse into all parts of the guide pipe 501, thereby reducing its internal temperature. The heat exchange medium is introduced into the cooling cylinder 100 and passes through the first dispersing net 502 and the second dispersing net 503 in sequence, thereby being dispersed into several small heat exchange mediums, so that the residual heat inside can be fully dissipated, facilitating comprehensive cooling.

[0049] Please see Figure 2-3Both the first dispersion mesh 502 and the second dispersion mesh 503 are made of copper. The mesh size of the first dispersion mesh 502 is larger than that of the second dispersion mesh 503. The first dispersion mesh 502 and the second dispersion mesh 503, made of copper, have good thermal conductivity. After the heat exchange medium comes into contact with and disperses with them, the heat dissipated is quickly introduced into the guide pipe 501 and absorbed by the aqueous solution.

[0050] Please see Figure 2 and Figure 4-5 The water-cooling mechanism 600 includes an annular frame 601 sleeved on the outer end of the cooling cylinder 100. A flexible storage bladder 602 is fixedly connected inside the annular frame 601, and potassium nitrate powder is stored inside the flexible storage bladder 602. Two symmetrically arranged extrusion arc plates 608 are fixedly connected to both the left and right ends of the flexible storage bladder 602. Multiple pairs of T-shaped rods 605 are fixedly connected to the inner wall of the annular frame 601, and movable blocks 606 are sleeved on each pair of T-shaped rods 605. The extrusion arc plates 608 are located at... A pair of movable blocks 606 on the outer side are fixedly connected. A memory spring 607 is fitted onto each of a pair of T-shaped rods 605, and the outer ends of the memory springs 607 are fixedly connected to the annular frame 601 and the movable blocks 606, respectively. A guide pipe 609 is embedded between the flexible storage bladder 602, the annular frame 601, the cooling cylinder 100, and the guide pipe 501. The guide pipe 609 is connected to the interior of the flexible storage bladder 602 and the guide pipe 501, respectively. A motion-type jet is fixedly connected to the inner wall of the guide pipe 609. The nozzle 6010 and the guide tube 501 contain an aqueous solution. After the heat exchange medium dissipates heat, it is conducted into the guide tube 501 and absorbed by the aqueous solution. As the heat dissipates, the temperature rises. The memory spring 607 senses the temperature rise and deforms accordingly. The water cooling mechanism 600, through the extension of the memory spring 607, pushes the extrusion arc plate 608 towards the flexible storage bladder 602, extruding some of the potassium nitrate powder inside the flexible storage bladder 602 into the guide tube 501, where it dissolves in the aqueous solution, absorbs heat, and cools down, facilitating the continuous absorption of heat. In this design, the deformation of the memory spring 607 does not extend continuously with temperature changes, so the extrusion and spraying of potassium nitrate powder is intermittent. This allows for multiple extrusions of potassium nitrate powder to dissolve in the aqueous solution based on temperature changes, enabling multiple uses. Furthermore, the cooling cylinder 100 and the sealing disc 200 are connected and fixed with screws, allowing for disassembly and convenient maintenance and replacement of the internal components and mechanisms of the cooling cylinder 100.

[0051] Please see Figure 2 and Figure 4-5A feeding tube 603 is embedded between the flexible storage bladder 602 and the annular frame 601, and the feeding tube 603 penetrates the annular frame 601. The feeding tube 603 is connected to the interior of the flexible storage bladder 602, and a sealing plug 604 is interference-fitted to the feeding tube 603. The addition of potassium nitrate powder is achieved through the feeding tube 603 and the sealing plug 604. The inner wall of the movable block 606 has two symmetrically shaped spherical grooves, and both spherical grooves are rotatably connected to... The outer end of the ball bearing 6061 contacts the outer end of the T-shaped rod 605. The memory spring 607 is made of shape memory alloy material. The initial state of the memory spring 607 is the contracted state. The ball bearing 6061 makes the movement of the movable block 606 smoother and more convenient. The memory spring 607 made of shape memory alloy material has a two-way memory effect. It deforms and extends after the temperature rises to 40°C, and returns to the initial state after the temperature drops.

[0052] Please see Figure 2 and Figure 6 The air-cooling mechanism 700 includes a first built-in ring 701 fixedly connected to the inner wall of the cooling cylinder 100, and a third built-in ring 703 fixedly connected to the left end of the sealing circular plate 200 on the right side. The diameter of the third built-in ring 703 matches the diameter of the discharge pipe 400. A second built-in ring 702 is provided between the first built-in ring 701 and the third built-in ring 703. A connecting frame 704 is sequentially connected between the first built-in ring 701, the second built-in ring 702 and the third built-in ring 703. The interior of the connecting frame 704 is filled with ammonium chloride powder, and the inner wall of the connecting frame 704 is filled with a diamond powder layer. When the heat exchange medium passes through the connecting frame 704 in the air-cooling mechanism 700, its residual heat is conducted to the interior of the connecting frame 704 through the diamond powder layer. The ammonium chloride powder absorbs the heat and begins to decompose into hydrogen chloride gas and ammonia gas, fully absorbing the residual heat of the heat exchange medium, so that it is fully cooled, causing its temperature to drop rapidly and enhancing the cooling effect.

[0053] In this invention, the refrigeration device 504 is first driven to cool, causing cold air to diffuse throughout the guide pipe 501. The heat exchange medium, after passing through the feed pipe 300 and opening the two rubber seals 301, enters the cooling cylinder 100. It then passes through the first dispersing net 502 into the guide pipe 501. The first dispersing net 502 disperses the medium into small streams of heat exchange medium. During this dispersion process, residual heat within the medium is conducted through the first dispersing net 502 to the guide pipe 501 and absorbed by the aqueous solution. As heat dissipates, the temperature rises. The memory spring 607, affected by the temperature, deforms and extends, causing the movable block 606 to move on the T-shaped rod 605. This pushes the extrusion arc plate 608 towards the flexible storage bladder 602, compressing the flexible storage bladder 602. 2. Some potassium nitrate powder inside is sprayed into the guide pipe 501, dissolves in the aqueous solution, absorbs heat and cools down, facilitating the continuous absorption of heat. As small streams of heat exchange medium are discharged through the second dispersion net 503, they are further dispersed into even smaller streams, allowing the residual heat inside to dissipate further. Then they converge into the connecting frame 704. Due to the continuous dispersion and mutual exchange of positions of the heat exchange medium, the residual heat inside is also dissipated. It is conducted through the diamond powder layer to the interior of the connecting frame 704. The ammonium chloride powder absorbs the heat and begins to decompose into hydrogen chloride gas and ammonia gas, fully absorbing the residual heat of the heat exchange medium. Combined with the cooling device 504, it is fully cooled, causing its temperature to drop rapidly, enhancing the cooling effect, and facilitating subsequent recycling.

[0054] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A method for artificial fracturing and heat transfer in a single well in hot dry rock formation, characterized in that: Includes the following steps: S1. First, determine the burial depth of the hot dry rock, and then carry out drilling using drilling machines according to the planned drilling plan. Next, drill two horizontal wells in the same direction on the well wall. S2. Inject cement slurry containing high thermal conductivity material into the main well and two horizontal wells of the dry hot rock, and then use supercritical carbon dioxide as the fracturing medium to form artificially fractured rock layers in the dry hot rock mass using fracturing technology. S3. Heat exchange devices and transmission pipelines are installed inside the main dry hot rock well and two horizontal wells. Then, surface wellhead heat exchange equipment and cooling devices are installed around the wellhead to form a circulating heat exchange loop to realize the extraction of dry hot rock thermal energy. The cooling device in S3 includes a cooling cylinder (100). Both ends of the cooling cylinder (100) are threaded with sealing discs (200). The left end of the sealing disc (200) on the left side is fixedly connected with a feed pipe (300), and the right end of the sealing disc (200) on the right side is fixedly connected with a discharge pipe (400). The feed pipe (300) and the discharge pipe (400) are both connected to the interior of the cooling cylinder (100). The interior of the cooling cylinder (100) is provided with a driving cooling mechanism (500) and an air cooling mechanism (700). The cooling cylinder (100) is provided with a water cooling mechanism (600). The driving cooling mechanism (500) includes a guide pipe (501) embedded in the inner wall of the cooling cylinder (100), and a first dispersing net (502) and a second dispersing net (503) are fixedly connected to the inner wall of the guide pipe (501). A refrigeration device (504) is installed inside the cooling cylinder (100). The water-cooling mechanism (600) includes an annular frame (601) sleeved on the outer end of the cooling cylinder (100). A flexible storage bladder (602) is fixedly connected inside the annular frame (601), and potassium nitrate powder is disposed inside the flexible storage bladder (602). Two vertically symmetrical extrusion arc plates (608) are fixedly connected to both the left and right ends of the flexible storage bladder (602). Multiple pairs of T-shaped rods (605) are fixedly connected to the inner wall of the annular frame (601). Movable blocks (606) are sleeved on each pair of T-shaped rods (605), and the extrusion arc plates (608) are fixed to a pair of movable blocks (606) located on the outer side. The connection is as follows: a memory spring (607) is fitted on each of the two T-shaped rods (605), and the outer ends of the memory springs (607) are fixedly connected to the annular frame (601) and the movable block (606) respectively. A guide tube (609) is embedded between the flexible storage bladder (602), the annular frame (601), the cooling tube (100), and the guide tube (501), and the guide tube (609) is connected to the interior of the flexible storage bladder (602) and the guide tube (501) respectively. A motion-type spray nozzle (6010) is fixedly connected to the inner wall of the guide tube (609), and an aqueous solution is provided inside the guide tube (501).

2. The method for artificial fracturing heat transfer in a single well in dry hot rock according to claim 1, characterized in that: The inner wall of the feed pipe (300) is rotatably connected to two rubber seals (301), and the two rubber seals (301) are in close contact with each other.

3. The method for artificial fracturing heat transfer in a single well in hot dry rock according to claim 1, characterized in that: Both the first dispersing mesh (502) and the second dispersing mesh (503) are made of copper. The mesh size of the first dispersing mesh (502) is larger than that of the second dispersing mesh (503).

4. The method for artificial fracturing heat transfer in a single well in hot dry rock according to claim 1, characterized in that: A feeding tube (603) is embedded between the flexible storage bladder (602) and the annular frame (601), and the feeding tube (603) passes through the annular frame (601). The feeding tube (603) is connected to the interior of the flexible storage bladder (602), and the feeding tube (603) is press-fitted with a sealing plug (604).

5. The method for artificial fracturing heat transfer in a single well in hot dry rock according to claim 1, characterized in that: The inner wall of the movable block (606) has two symmetrical spherical grooves, and the inside of each spherical groove is rotatably connected with a ball (6061). The outer end of the ball (6061) is in contact with the outer end of the T-shaped rod (605). The memory spring (607) is made of shape memory alloy material. The initial state of the memory spring (607) is the contracted state.

6. The method for artificial fracturing heat transfer in a single well in hot dry rock according to claim 1, characterized in that: The air-cooling mechanism (700) includes a first built-in ring (701) fixedly connected to the inner wall of the cooling cylinder (100), a third built-in ring (703) fixedly connected to the left end of the sealing circular plate (200) on the right side, and the diameter of the third built-in ring (703) matches the diameter of the discharge pipe (400). A second built-in ring (702) is provided between the first built-in ring (701) and the third built-in ring (703). A connecting frame (704) is sequentially connected between the first built-in ring (701), the second built-in ring (702) and the third built-in ring (703), and the interior of the connecting frame (704) is provided with ammonium chloride powder. The inner wall of the connecting frame (704) is provided with a diamond powder layer.

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