Apparatus and method for constructing an artificial thermal reservoir based on ultra-high temperature thermal fracturing of hot dry rock

Abstract

The application discloses a device and method for constructing an artificial thermal reservoir based on super-high-temperature thermal cracking of hot dry rock, and belongs to the technical field of enhanced geothermal systems. The device for constructing an artificial thermal reservoir comprises coaxially nested inner-layer pipelines and outer-layer annular gap pipelines. An annular space between the outer wall of the inner-layer pipelines and the inner wall of the outer-layer annular gap pipelines forms an annular oxidant channel. A plurality of inner nozzles are arranged on the wall of the inner-layer pipelines, and a plurality of outer nozzles are arranged on the wall of the outer-layer annular gap pipelines. The inner and outer nozzles are connected through magnetic attraction. The device avoids the risk of the fuel and the oxidant reacting in a non-designated area due to early mixing through non-equal-length nozzle arrangement, magnetic attraction positioning and flow channel separation technology, realizes efficient and controllable injection of the fuel and the oxidant and thermal cracking regulation, and significantly improves the reservoir reconstruction efficiency and engineering safety. The device is suitable for artificial reconstruction of hot dry rock reservoirs and development of enhanced geothermal systems.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of enhanced geothermal systems, and particularly relates to an artificial heat reservoir construction device and method based on super-high-temperature thermal fracture dry hot rock. BACKGROUND

[0002] Under the background of the intensifying contradiction between global energy supply and demand, geothermal energy has become a key development direction due to its sustainability. Dry hot rock is usually a dense rock body (such as volcanic rock, metamorphic rock) with low porosity and low permeability, and has very poor natural permeability, so a heat exchange channel needs to be formed through artificial modification. There are usually the following ways in the traditional artificial modification technology:

[0003] 1. Hydraulic fracturing: high-pressure water is injected into the rock body to form a fracture network, but there are problems of uncontrollable structure and low heat extraction efficiency;

[0004] 2. Chemical stimulation: acid solution is injected to dissolve minerals (such as feldspar and quartz) to expand the pore, but the concentration needs to be controlled to avoid damage to the rock structure; a new type of stimulating liquid (such as a compound formula of fluoroboric acid and organic phosphonic acid) can reduce the risk of secondary sedimentation;

[0005] 3. Combined process: combining hydraulic fracturing and chemical stimulation to optimize the permeability of the fracture;

[0006] However, the implementation of artificial reservoir modification of the enhanced geothermal system (EGS) still faces multiple bottlenecks by relying on hydraulic fracturing or chemical stimulation: on the technical level, there is a lack of precise fracture control technology, resulting in poor connectivity of the underground fracture network; the water-rock reaction mechanism under high temperature and high pressure conditions is complex, affecting the permeability improvement effect; the imbalance of reservoir thermal stress leads to accelerated heat energy decay and instability risk of ultra-deep well drilling engineering; stress sensitivity may cause further decrease of permeability during the production process; environmental risks involve the probability of induced earthquake events, chemical pollution of fracturing fluid and destruction of the integrity of the underground water system, and regional water resource pressure caused by high water consumption; and it causes sharp contradictions of insufficient economic efficiency and energy output ratio in the whole life cycle. SUMMARY

[0007] The application overcomes the shortcomings of the prior art and proposes an artificial heat reservoir construction device and method based on super-high-temperature thermal fracture dry hot rock, which realizes efficient and controllable injection of fuel and oxidizer and thermal-induced fracture control, improves the reservoir modification efficiency and engineering safety, and solves the problems of poor precision of fracture control and low modification efficiency in the current enhanced geothermal system.

[0008] The application is realized by the following technical solutions:

[0009] The artificial hot reservoir construction device based on super-high temperature thermal cracking dry hot rock mass comprises coaxially nested inner layer pipes and outer layer annular gap pipes, and an annular oxidant channel is formed between the outer wall of the inner layer pipes and the inner wall of the outer layer annular gap pipes; the inner layer pipes are used for conveying fuel to the dry hot rock mass; a plurality of groups of inner injection ports are arranged on the pipe wall of the inner layer pipes in an axial direction, a plurality of groups of outer injection ports are arranged on the pipe wall of the outer layer annular gap pipes in an axial direction, two adjacent groups of outer injection ports are connected through strip-shaped magnetic attraction bosses arranged in the axial direction of the outer layer annular gap pipes, the inner injection ports are butted through magnetic attraction with the outer injection ports, the number of the outer injection ports is greater than that of the inner injection ports, and the inner layer pipes are connected with a driving mechanism to drive the inner layer pipes to move back and forth in the axial direction of the outer layer annular gap pipes.

[0010] Further, the inner layer pipes are connected with kerosene pipes, and the outer layer annular gap pipes are connected with oxygen pipes.

[0011] Further, each group of inner injection ports comprises a plurality of inner layer pipe injection ports, and the plurality of inner layer pipe injection ports are uniformly arranged in the circumferential direction of the inner layer pipes; the axis of the inner layer pipe injection port is perpendicular to the axis of the inner layer pipe.

[0012] Further, an inner layer pipe end magnetic attraction boss is arranged at the outer port of the inner layer pipe injection port; and a displacement sensor is arranged in the inner layer pipe end magnetic attraction boss.

[0013] Further, each group of outer injection ports comprises a plurality of outer layer pipe injection ports, and the plurality of outer layer pipe injection ports are uniformly arranged in the circumferential direction of the outer layer annular gap pipes; the inner layer pipe injection port is butted through magnetic attraction with the corresponding outer layer pipe injection port.

[0014] Further, the axis of the outer layer pipe injection port is perpendicular to the axis of the outer layer annular gap pipe, and the length of the outer layer pipe injection port is less than that of the inner layer pipe injection port.

[0015] Further, the inner port of the outer layer pipe injection port is located on the inner side of the outer layer annular gap pipe, and the outer port of the outer layer pipe injection port is flush with the outer wall of the outer layer annular gap pipe; the inner port of the outer layer pipe injection port is made of a permanent magnet which is magnetically matched with the inner layer pipe end magnetic attraction boss, and the outer port of the inner layer pipe end magnetic attraction boss is butted through magnetic attraction with the inner port of the outer layer pipe injection port.

[0016] Further, the strip-shaped magnetic attraction boss is arranged between two adjacent outer layer pipe injection ports in the same column; and the width of the strip-shaped magnetic attraction boss is equal to the outer diameter of the inner layer pipe end magnetic attraction boss.

[0017] The artificial hot reservoir construction method based on super-high temperature thermal cracking dry hot rock mass adopts the artificial hot reservoir construction device based on super-high temperature thermal cracking dry hot rock mass, and comprises the following steps:

[0018] S1, the artificial hot reservoir construction device is placed in the horizontal well located in the target area dry hot rock layer, in the initial state, the outer nozzle and the inner nozzle are coaxially aligned by magnetic attraction;

[0019] S2, fuel is quantitatively transported into the dry hot rock layer through the inner layer pipeline, after the fuel diffuses in the dry hot rock layer and forms a continuous fuel belt, the inner layer pipeline is driven to displace along the axial direction by the driving mechanism, and the inner nozzle is synchronously closed;

[0020] S3, excess oxidant is injected through the outer annular gap pipeline, the excess oxidant enters the dry hot rock layer from the outer nozzle through the annular oxidant channel, and an exothermic oxidation reaction occurs between the fuel and the excess oxidant; the accumulated thermal stress of the rock matrix is generated due to the difference in the thermal expansion coefficient, and the network of rock mass cracks is induced to expand.

[0021] Further, after step S1, high-purity helium is introduced through the annular gap between the outer annular gap pipeline and the inner layer pipeline, the high-purity helium is injected into the wellbore of the horizontal well through the outer nozzle which is not connected with the inner nozzle, a stable laminar flow is formed, and residual active gas and liquid impurities in the wellbore are removed.

[0022] The beneficial effects generated by the present application relative to the prior art are:

[0023] 1, the present application avoids the risk of early mixing and reaction of fuel and oxidant in non-designated areas by non-equal-length nozzle layout, magnetic positioning and flow channel separation technology, realizes efficient and controllable injection of fuel and oxidant and thermal cracking regulation, and significantly improves reservoir reconstruction efficiency and engineering safety.

[0024] 2, based on the three-dimensional geological model of the reservoir, kerosene is injected through the inner layer pipeline to form a continuous fuel belt around the pipeline; and excess oxygen is injected through the outer annular gap at high pressure to trigger the self-sustaining oxidation reaction of kerosene in the high-temperature rock layer (T≥80℃); the reaction releases heat to induce a local thermal stress field (peak temperature≥500℃), and the network of rock matrix is broken through the difference in thermal expansion coefficient; not only breaks through the limitations of traditional hydraulic fracturing, but also has extremely high economic efficiency compared with it, provides a new method for enhanced geothermal system development, and can realize artificial cracking of deeper formations, increase the permeability, and realize the volume reconstruction of the target reservoir.

[0025] 3, the present application can realize efficient thermal cracking, and the reservoir permeability is improved by 2~3 orders of magnitude through the thermal-mechanical coupling cracking mechanism; through the flow channel physical isolation and excess oxygen supply strategy (oxygen-fuel ratio≥1.5), complete combustion is ensured, and the safety is higher, and the super deep well working condition is compatible, and the modularization rapid deployment is supported. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a layout schematic diagram of the artificial hot reservoir construction device of the present application;

[0027] Figure 2 is the schematic diagram of the inner pipe structure of the present application;

[0028] Figure 3 is the schematic diagram of the outer annular pipe structure of the present application;

[0029] Figure 4 is the schematic diagram of the whole structure of the outer annular pipe and the inner pipe;

[0030] Figure 5 is the cross-sectional view of the outer annular pipe and the inner pipe;

[0031] Figure 6 is the cross-sectional view of the inner pipe injection port coaxially aligned with the outer pipe injection port for kerosene injection;

[0032] Figure 7 is the cross-sectional view of the inner pipe with axial displacement, in which the inner pipe injection port is mechanically closed;

[0033] Figure 8 is the schematic diagram of the fracture network formed in Example 1;

[0034] Figure 9 is the schematic diagram of the fracture network formed in Example 2:

[0035] wherein 1 is the inner pipe, 2 is the outer annular pipe, 4 is the inner pipe injection port, 5 is the outer pipe injection port, 6 is the strip-shaped magnetic attraction boss, 7 is the inner pipe end magnetic attraction boss, and 8 is the horizontal well. DETAILED DESCRIPTION

[0036] In order to make the technical problems to be solved by the present application, the technical solutions and beneficial effects more clearly understood, the present application will be further described in detail in conjunction with the embodiments and the drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. The technical solutions of the present application are described in detail below in conjunction with the embodiments and the drawings, but the protection scope is not limited thereto. Example 1

[0037] Referring to Figures 1 to 7 , the present embodiment proposes an artificial thermal reservoir construction device based on ultra-high temperature thermal cracking dry hot rock, which comprises a coaxially nested inner pipe 1 and an outer annular pipe 2, and a ring-shaped oxidizing agent channel is formed between the outer wall of the inner pipe 1 and the inner wall of the outer annular pipe 2. The inner pipe 1 is connected with a kerosene pipe, and the outer annular pipe 2 is connected with an oxygen pipe. The inner pipe 1 is used for directional delivery of kerosene (C 12 H 26 ), and the outer annular pipe 2 is used for high-pressure injection of oxygen (O2).

[0038] The inner layer pipe 1 is provided with a plurality of groups of inner spray ports which are arranged axially and spaced apart, each group of inner spray ports including five inner layer pipe spray ports 4 which are uniformly arranged circumferentially along the inner layer pipe 1; the axis of the inner layer pipe spray port 4 is perpendicular to the axis of the inner layer pipe 1, and the outer end of the inner layer pipe spray port 4 is provided with an inner layer pipe end magnetic attraction boss 7; the inner layer pipe end magnetic attraction boss 7 is provided with a displacement sensor; the length of the inner layer pipe spray port 4 is d2, and the outer diameter of the inner layer pipe end magnetic attraction boss 7 is r1;

[0039] The outer layer annular gap pipe 2 is provided with a plurality of groups of outer spray ports which are arranged axially and spaced apart, each group of outer spray ports including five outer layer pipe spray ports 5 which are uniformly arranged circumferentially along the outer layer annular gap pipe 2; the number of outer layer pipe spray ports 5 is greater than the number of inner layer pipe spray ports 4, and the inner layer pipe spray port 4 can be butted against the corresponding outer layer pipe spray port 5; the axis of the outer layer pipe spray port 5 is perpendicular to the axis of the outer layer annular gap pipe 2, the length of the outer layer pipe spray port 5 is d1, and d2>d1; in this embodiment, the length-diameter ratio of the inner layer pipe spray port 4 and the outer layer pipe spray port 5 is 2:1-5:1.

[0040] The inner end of the outer layer pipe spray port 5 is located inside the outer layer annular gap pipe 2, and the outer end of the outer layer pipe spray port 5 is flush with the outer wall of the outer layer annular gap pipe 2; the inner end of the outer layer pipe spray port 5 is made of a permanent magnet which is magnetically matched with the inner layer pipe end magnetic attraction boss 7, the outer diameter of the inner end of the outer layer pipe spray port 5 is r2, r 1= r2; the outer end of the inner layer pipe end magnetic attraction boss 7 can be magnetically attracted and butted against the inner end of the outer layer pipe spray port 5.

[0041] The outer layer annular gap pipe 2 is provided with a strip-shaped magnetic attraction boss 6 along the axis thereof, and each strip-shaped magnetic attraction boss 6 is arranged between two adjacent outer layer pipe spray ports 5 in the same column; the width of the strip-shaped magnetic attraction boss 6 is r3, r 1= r3; the strip-shaped magnetic attraction boss 6 can precisely butt the outer layer pipe spray port 5 against the inner layer pipe end magnetic attraction boss 7 of the inner layer pipe spray port 4 as a magnetic attraction guide channel.

[0042] The inner layer pipe 1 is connected with a driving mechanism, and the driving mechanism drives the inner layer pipe 1 to move back and forth along the axis of the outer layer annular gap pipe 2; it should be noted that the driving mechanism is an existing device, and an electric push rod is used in this embodiment;

[0043] In use, the artificial heat reservoir construction device is vertically or obliquely implanted into the target depth of hot dry rock layer, the alignment state of the inner pipe jet port 4 and the outer pipe jet port 5 is controlled through the axial displacement of the inner pipe 1, when the inner pipe jet port 4 is connected with the outer pipe jet port 5 through the inner pipe end magnetic attraction boss 7, the kerosene can be quantitatively delivered to the hot dry rock layer through the inner pipe 1, then the flow channel is switched, the inner pipe 1 is driven to move along the axial direction through the driving mechanism, when the offset reaches the preset threshold, the inner pipe jet port 4 can be closed through the strip-shaped magnetic attraction boss 6 on the inner wall of the outer annular gap pipe 2, at this time, the excess oxygen can be injected into the hot dry rock through the outer pipe jet port 5 of the outer annular gap pipe 2, and fully reacts with the kerosene to realize the thermal-induced crack strengthening in the hot dry rock. Example 2

[0044] Referring to Figure 8 The embodiment provides an artificial heat reservoir construction method based on super-high-temperature thermal fracture hot dry rock, in the embodiment, the target region hot dry rock is granite, the buried depth is 4280 m, and the in-situ temperature is 220 DEG C; the artificial heat reservoir construction device provided in the embodiment 1 is used, and the following steps are included.

[0045] S1. Composite pipe deployment:

[0046] Two groups of parallel horizontal wells 8 are deployed, the horizontal well 8 horizontal section spacing is 150 m, the initial permeability is low, and no natural fracture connection is detected. A group of artificial heat reservoir construction devices are implanted in the two horizontal wells 8 by using directional drilling technology, the outer annular gap pipe 2 diameter is 219 mm (wall thickness 12 mm), the inner pipe 1 diameter is 114 mm, and the inner pipe 1 and the outer annular gap pipe 2 are made of high-temperature creep-resistant nickel-based alloy material. The outer annular gap pipe 2 is provided with 30 groups of outer pipe jet ports 5 (d1=8 mm), the inner pipe wall of the inner pipe 1 is provided with 20 groups of inner pipe jet ports 4 (d2=25 mm), and in the initial state, the inner pipe jet port 4 of the inner pipe 1 is coaxially aligned with the corresponding outer pipe jet port 5 through magnetic attraction, and the alignment accuracy is ≤0.5 mm.

[0047] S2. Inert environment construction:

[0048] High-purity helium is introduced through the annular gap between the outer annular gap pipe 2 and the inner pipe 1, the high-purity helium is sprayed into the wellbore through the outer pipe jet port 5 which is not connected with the inner pipe jet port 4, the helium introduction time lasts for 10-15 minutes, which aims to form a stable laminar flow, effectively remove the active gases such as residual oxygen, water vapor and liquid impurities in the wellbore, and ensure that the oxygen content in the established inert environment is within a safe range, thereby providing a safe and controllable initial condition for the subsequent non-premixed oxidation reaction.

[0049] S3. Fuel permeation control:

[0050] Based on the fracture distribution data of the three-dimensional geological model of the borehole, kerosene (C 12 H 26 ) is quantitatively transported to the hot dry rock layer through the inner pipeline 1, and the flow rate of kerosene is controlled below 1 m / s to prevent static electricity from being generated during the transportation process, and continuous injection is carried out until the rock fractures form a continuous fuel belt. Specifically, in this embodiment, kerosene is simultaneously injected into the inner pipeline 1 of the two groups of horizontal wells 8, so that the fuel diffuses to the area between the two wells; after a period of time, it is confirmed through tracer monitoring that a continuous fuel belt is formed between the two wells.

[0051] S4. Flow channel switching operation:

[0052] The inner pipeline 1 in the two groups of horizontal wells 8 is driven by a driving mechanism to displace along the axis direction, and the fuel passage is synchronously closed. The displacement amount is fed back in real time by a displacement sensor embedded in the magnetic attraction boss 7 at the end of the inner pipeline, and when the displacement amount reaches ΔL=2r, the inner pipeline injection port 4 of the inner pipeline 1 is completely covered by the inner wall of the outer annular gap pipeline 2, and the kerosene is mechanically blocked from being injected out. At this time, the inner pipeline injection port 4 is in a closed state, and the outer pipeline injection port 5 is in an open state; the displacement control accuracy of the displacement sensor reaches ±0.1 mm.

[0053] S5. Oxidation reaction triggering:

[0054] Excess oxygen is injected into the outer annular gap pipeline 2 through the oxygen pipeline, and the excess oxygen enters the hot dry rock layer, so that the kerosene at the double wells simultaneously undergoes a violent oxidation reaction.

[0055] In order to make the kerosene fully react, combined with the chemical equation of kerosene oxidation, the molar ratio of oxygen to kerosene is controlled to be 35:1 to 36:1, and the non-premixed oxidation reaction of kerosene and oxygen is catalyzed by the original temperature (80-200°C) of the hot dry rock layer. The temperature gradient of the thermal stress field is 80-200°C / m, and the action time is ≥30 minutes; the reaction heat release rate is ≥500 kJ / (m 3 ·s).

[0056] Excess oxygen is injected into the outer annular gap pipeline 2 through the outer annular gap high-pressure injection, and the kerosene self-sustaining oxidation reaction is triggered in the high-temperature rock layer (T≥80°C):

[0057] C 12 H 26 +18.5O2→12CO2+13H2O+release heat value≈45 MJ / kg;

[0058] The reaction heat release induces a local thermal stress field (peak temperature≥500°C), and the rock matrix network is broken through the difference in thermal expansion coefficient.

[0059] S6. Thermal-induced crack strengthening:

[0060] The heat released by the oxidation reaction continues to act in the hot dry rock for 30-120 minutes, providing the necessary time for the effective conduction and accumulation of heat energy in the rock mass, causing the accumulation of thermal stress due to the difference in thermal expansion coefficients of the rock matrix, and when the thermal stress value exceeds the tensile strength of the rock by 3-5 MPa, the network of cracks in the rock mass expands, and the crack density increases by 40%-70%; the excess stress of 3-5 MPa is a safety margin to compensate for the uncertainty caused by the heterogeneity of the rock mass and the fluctuation of the in-situ stress field, ensuring the effectiveness and universality of the thermal cracking effect;

[0061] S7. Circulating cracking:

[0062] After the thermal cracking is completed, the inner pipe 1 is reset to the initial alignment position, and kerosene is injected again to repeat the above operation steps to further increase the permeability of the target area. The peak heat flux density released by the oxidation of kerosene reaches 3.2 x 10 6 W / m 3 , the local temperature of the rock mass breaks through 800℃, and the rock starts to crack, and microseismic monitoring shows that the cracks expand from the two wells, and the kerosene and oxygen are repeatedly injected to make the oxidation reaction occur repeatedly, and finally the crack bridging is achieved through stress interference. Example 3

[0063] Referring to Figure 9 , this embodiment proposes a method for constructing an artificial thermal reservoir based on super-high temperature thermal cracking of hot dry rock. This engineering case is aimed at the development of deep granite thermal reservoirs, and adopts the Enhanced Geothermal System (EGS) technical route. The target reservoir is located at a vertical depth of 4280m, and the in-situ temperature gradient reaches 220℃. The artificial thermal reservoir construction device proposed in Example 1 is used, and the following steps are included:

[0064] S1. Deployment of composite pipe:

[0065] The well pattern is deployed in a horizontal well-double straight well combined configuration, with a horizontal section length of 1500m, penetrating through the low permeability granite mass. An artificial thermal reservoir construction device is implanted at the position of the horizontal section, the outer annular pipe 2 has a diameter of 219mm (wall thickness of 12mm), and the inner pipe 1 has a diameter of 114mm. Both the inner pipe 1 and the outer annular pipe 2 are made of high-temperature creep-resistant nickel-based alloy material. The outer annular pipe 2 is configured with 30 groups of outer pipe injection ports 5 (d1=8mm), and the inner pipe wall of the inner pipe 1 is provided with 20 groups of inner pipe injection ports 4 (d2=25mm). In the initial state, the inner pipe injection ports 4 of the inner pipe 1 and the corresponding outer pipe injection ports 5 are kept coaxially aligned by magnetic attraction, and the alignment accuracy is ≤0.5mm.

[0066] Steps S2-S7 are the same as in Example 2.

[0067] The embodiment realizes the cross-well engineering reconstruction of deep dry hot rock reservoir by building a high-conductivity fracture network between unconnected isolated horizontal wells through the thermal-chemical coupling cracking mechanism. Compared with the traditional hydraulic fracturing technology, it has high economic efficiency. The technical system breaks through the well spacing limit of the traditional enhanced geothermal system (EGS) through the control strategy of fuel directional preposition and precise oxidation triggering, and provides a technical paradigm with industrial promotion value for the development of deep low-permeability dry hot rock. The unique non-hydraulic fracturing mechanism not only eliminates the risk of fracturing fluid pollution, but also realizes the synergistic optimization of reservoir reconstruction efficiency and engineering safety through the dynamic balance control of thermal cracking and shock wave.

[0068] In order to make the public have a thorough understanding of the present application, the specific details are described in detail in the above preferred embodiments of the present application, and the present application can also be completely understood without the description of these details to those skilled in the art. Without departing from the principles of the present application, several improvements and refinements can also be made, which should be considered as the protection scope of the present application.

Claims

1. An apparatus for the construction of an artificial thermal reservoir based on superhigh-temperature thermal fracturing of hot dry rock, characterized in that, The device comprises coaxially nested inner pipe (1) and outer annular pipe (2), and the annular space between the outer wall of the inner pipe (1) and the inner wall of the outer annular pipe (2) forms an annular oxidant channel; the inner pipe (1) is used for conveying fuel to the hot dry rock; a plurality of groups of inner nozzles are arranged on the wall of the inner pipe (1) in an axial direction, a plurality of groups of outer nozzles are arranged on the wall of the outer annular pipe (2) in an axial direction, two adjacent groups of outer nozzles are connected through strip-shaped magnetic attraction boss (6), the strip-shaped magnetic attraction boss (6) is arranged in an axial direction along the outer annular pipe (2); the inner nozzle and the outer nozzle are butted through magnetic attraction; the number of outer nozzles is greater than that of inner nozzles; the inner pipe (1) is connected with a driving mechanism, and the inner pipe (1) is driven to move back and forth along the axial direction of the outer annular pipe (2) through the driving mechanism; Each group of inner nozzles comprises a plurality of inner pipe injection ports (4), and an inner pipe end magnetic attraction boss (7) is arranged at the outer port of the inner pipe injection port (4); each group of outer nozzles comprises a plurality of outer pipe injection ports (5), the inner port of the outer pipe injection port (5) is located inside the outer annular pipe (2), and the outer port of the outer pipe injection port (5) is flush with the outer wall of the outer annular pipe (2); the inner port of the outer pipe injection port (5) is made of a permanent magnet which is magnetically matched with the inner pipe end magnetic attraction boss (7), and the outer port of the inner pipe end magnetic attraction boss (7) is butted with the inner port of the outer pipe injection port (5) through magnetic attraction.

2. The artificial hot reservoir construction apparatus based on super-high-temperature hot fracture of hot dry rock according to claim 1, characterized by, The inner pipe (1) is connected with a kerosene pipe, and the outer annular pipe (2) is connected with an oxygen pipe.

3. The artificial hot reservoir construction apparatus based on super-high-temperature hot fracture of hot dry rock according to claim 1, characterized by, A plurality of inner pipe injection ports (4) are uniformly arranged in a circumferential direction along the inner pipe (1); the axis of the inner pipe injection port (4) is perpendicular to the axis of the inner pipe (1).

4. The artificial hot reservoir construction apparatus based on super-high-temperature hot fracture of hot dry rock according to claim 3, characterized by, The inner pipe end magnetic attraction boss (7) is internally provided with a displacement sensor.

5. The artificial hot reservoir construction based on super-high-temperature hot fracture dry hot rock mass according to claim 4, characterized in that, A plurality of outer pipe injection ports (5) are uniformly arranged in a circumferential direction along the outer annular pipe (2); the inner pipe injection port (4) is butted with the corresponding outer pipe injection port (5) through magnetic attraction.

6. The artificial hot reservoir construction based on super-high-temperature hot fracture dry hot rock mass according to claim 5, characterized in that, The axis of the outer pipe injection port (5) is perpendicular to the axis of the outer annular pipe (2), and the length of the outer pipe injection port (5) is less than that of the inner pipe injection port (4).

7. The artificial hot reservoir construction based on super-high-temperature hot fracture dry hot rock mass according to claim 5, characterized in that, The strip-shaped magnetic attraction boss (6) is correspondingly arranged between two adjacent outer pipe injection ports (5) in the same column; the width of the strip-shaped magnetic attraction boss (6) is equal to the outer diameter of the inner pipe end magnetic attraction boss (7).

8. A method of artificial hot reservoir construction based on superhigh-temperature thermal fracturing of hot dry rock, characterized in that, The device is used for constructing an artificial heat reservoir based on the hot dry rock which is broken by super-high temperature, and comprises the following steps: S1, the device is placed into a horizontal well (8) in a target area hot dry rock layer, in an initial state, the outer nozzle and the inner nozzle are coaxially aligned through magnetic attraction; S2, fuel is quantitatively conveyed into the hot dry rock layer through the inner pipe (1), after the fuel diffuses in the hot dry rock layer and forms a continuous fuel belt, the inner pipe (1) is driven to displace along the axial direction through the driving mechanism, and the inner nozzle is simultaneously closed; S3, injecting excess oxidizer through the outer annular gap pipe (2), the excess oxidizer enters the dry hot rock layer from the outer nozzle through the annular oxidizer channel, and has an exothermic oxidation reaction with the fuel; the rock matrix generates cumulative thermal stress due to the difference in thermal expansion coefficient, inducing the expansion of the rock mass network fracture.

9. The method of claim 8, wherein the artificial hot reservoir is constructed by super-high temperature thermal fracturing of hot dry rock. After step S1, high-purity helium is introduced through the annular gap between the outer annular gap pipe (2) and the inner pipe (1), the high-purity helium is sprayed into the wellbore of the horizontal well (8) through the outer nozzle which is not connected with the inner nozzle, a stable laminar flow is formed, and residual active gas and liquid impurities in the wellbore are removed.

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