A geothermal drilling device and method using carbon dioxide jet rotary drilling

Abstract

The present invention discloses a geothermal drilling device and method for carbon dioxide jet rotary drilling, which relates to the field of drilling technology and includes a drilling system, the drilling system including a drill bit, a drill pipe, a drilling rig, a drilling tower, and a mud pump, and also includes a jet system, the jet system including a dry ice abrasive machine, a control valve, a heating and cooling pressurizing device, and a control center; the drill bit is provided with a flushing liquid inlet and a jet water inlet, and the drill bit is provided with a drilling fluid channel and a jet channel respectively connected to the flushing liquid inlet and the jet water inlet; the drill bit is connected to the drill pipe via a connector; the dry ice abrasive machine is connected to the inner pipe of the drill pipe via the heating and cooling pressurizing device, and the mud pump is connected to the inner and outer pipe gaps of the drill pipe via the heating and cooling pressurizing device; the control valve is provided on the pipeline connecting the heating and cooling pressurizing device and the inner pipe of the drill pipe; the control valve, mud pump, drilling rig, dry ice abrasive machine, and heating and cooling pressurizing device are respectively electrically connected to the control center. The present invention can reduce drill bit wear, improve drilling efficiency, and reduce production costs.

Description

Technical Field

[0001] The present invention relates to the field of drilling technology, and in particular to a geothermal drilling device and method for carbon dioxide jet rotary drilling. Background Art

[0002] As drilling depth increases, the number of extremely hard rock formations encountered increases. This is particularly true in hot dry rock mining, where the majority of hot dry rock is hot and hard. This impacts drilling speeds and severe drill bit wear due to the impact of the hard rock. Furthermore, the high temperatures create a harsh operating environment for the drill bit, shortening its lifespan and leading to frequent downtime and bit replacements, severely impacting the efficiency of hot dry rock mining and increasing costs. In recent years, PDC drill bits have been primarily used abroad to address this issue by optimizing the drill bit structure, improving diamond quality, and increasing the pressure on bit during drilling. However, this approach places higher demands on drill bit processing technology, increases manufacturing costs, and cannot prevent the PDC surface layer from cracking and shedding when drilling hard rock. Currently, my country's primary approach to addressing hard rock formations is to weld high-strength blades to a soft matrix and employ high-pressure-on-bit drilling to increase drilling speeds. However, this still poses the problem of blade shedding. These methods still fail to address the high forces and rapid wear experienced by drill bits in hard rock, and they still suffer from low drilling speeds and high production costs. In order to speed up drilling efficiency in hard rock, a new technology is needed to solve these problems. Summary of the Invention

[0003] The purpose of the present invention is to provide a geothermal drilling device and method for carbon dioxide jet rotary drilling to solve the problems existing in the above-mentioned prior art, thereby reducing drill bit wear, improving drilling efficiency and reducing production costs.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a geothermal drilling device for carbon dioxide jet rotary drilling, comprising a drilling system including a drill bit, a drill rod, a drilling rig, a drilling tower and a mud pump, and a jet system including a dry ice abrasive machine, a control valve, a temperature riser and a pressure regulator and a control center;

[0006] The drilling end of the drill bit is provided with a flushing liquid inlet and a jet water inlet, and the drill bit is provided with a drilling fluid channel and a jet channel respectively connected to the flushing liquid inlet and the jet water inlet. The drill bit is connected to the drill pipe via a connector; the connector includes a connector inner tube and a connector outer tube, and the drill pipe includes a drill pipe inner tube and a drill pipe outer tube. The drilling fluid channel is connected to the inner and outer tube gaps of the drill pipe through the inner and outer tube gaps of the connector, and the jet channel is connected to the inner pipe of the drill pipe through the connector inner tube.

[0007] The dry ice abrasive machine is connected to the heating and pressurizing device and communicates with the inner tube of the drill pipe through the heating and pressurizing device. The mud pump is connected to the heating and pressurizing device and communicates with the inner and outer tube gaps of the drill pipe through the heating and pressurizing device. The control valve is provided on the pipeline connecting the heating and pressurizing device and the inner tube of the drill pipe.

[0008] The control valve, the mud pump, the drilling rig, the dry ice grinding machine and the temperature increasing and pressurizing device are electrically connected to the control center respectively.

[0009] Preferably, the drill bit is a cemented carbide full-drill drill bit, the drilling end of the drill bit is provided with three cemented carbide blades, and each of the cemented carbide blades is provided with a plurality of evenly distributed cemented carbide blades.

[0010] Preferably, a flushing fluid outlet is provided between each adjacent two carbide blades, the jet outlet is provided in the middle of the drill bit, the gap between the inner and outer tubes of the drill bit constitutes the drilling fluid channel, and the inner cavity of the inner tube of the drill bit constitutes the jet channel.

[0011] Preferably, a nozzle is provided between the jet channel and the jet water outlet, and a filter is provided between the nozzle and the jet water outlet.

[0012] Preferably, the lower ends of the connector inner tube and the connector outer tube are both provided with internal threads, which are used to be threadedly connected to the inner tube and outer tube of the drill bit, respectively; the upper end of the connector outer tube is provided with an internal thread, which is used to be threadedly connected to the lower end of the drill pipe outer tube; a clamping piece is provided inside the upper end of the connector inner tube, and a clamping joint that cooperates with the clamping piece is provided inside the lower end of the drill pipe inner tube; the clamping joint cooperates with the clamping piece to connect the connector inner tube and the drill pipe inner tube.

[0013] Preferably, the drill rod outer tube is provided with a sliding portion near the thread at its lower end, and a drill rod spring and two spring seats are sleeved on the sliding portion. The drill rod spring is arranged between the two spring seats, and the spring seat can slide axially along the sliding portion. The upper end of the drill rod outer tube is provided with a connecting flange, and the upper end of the drill rod outer tube is also provided with a shock absorber.

[0014] The present invention also provides a geothermal drilling method using carbon dioxide jet rotary drilling, based on the geothermal drilling device using carbon dioxide jet rotary drilling described above, comprising the following steps:

[0015] S1: Determine the borehole to be tested, install the drilling tower, the drilling rig, and the control center, excavate a mud pit, arrange the mud pump, and then install the dry ice grinder and the temperature-boosting pressurizer; connect the mud pump and the dry ice grinder to the temperature-boosting pressurizer using pipelines, and connect the temperature-boosting pressurizer to the drill pipe inner tube and the drill pipe outer tube using concentric pipelines, so that pressurized carbon dioxide and drilling fluid can flow into the drill pipe inner tube and the gap between the inner and outer tubes of the drill pipe, respectively, and install the control valve between the drill pipe inner tube and the inner tube of the concentric pipeline;

[0016] S2: Connecting the drill bit to the connector, installing the connector on the drill rod, installing the drill rod on the drilling rig and hanging it on the drilling tower;

[0017] S3: starting the mud pump to circulate the drilling fluid through the gap between the inner and outer tubes of the drill pipe and the annular space in the borehole, operating the winch of the drilling rig to lower the drill pipe to the bottom of the hole, and operating the rotator of the drilling rig to rotate and break the rock;

[0018] S4: The dry ice grinding machine is started to produce carbon dioxide required for the jet, and the carbon dioxide is transported to the heating and pressurizing device; the control valve is opened by the control center to transport the high-pressure carbon dioxide fluid to the inner tube of the drill pipe, and a high-pressure jet is generated at the bottom of the hole to crush the rock. After the rock is crushed for a period of time, the jet is stopped and the drilling rig is operated to perform rotary drilling;

[0019] S5: Repeat step S4 to repeatedly perform carbon dioxide jet rotary drilling.

[0020] Preferably, during the drilling process, the jet intensity and interval are adjusted by the control center according to the properties of the rock at the bottom of the hole.

[0021] Preferably, in step S1, a mud pool is excavated near a water source and a borehole, and the mud pump is arranged beside the pool.

[0022] Compared with the prior art, the present invention has achieved the following technical effects:

[0023] The geothermal drilling device and method for carbon dioxide jet rotary drilling provided by the present invention can, during the hot dry rock mining process, crush the rock by the carbon dioxide jet, causing cracks in the rock to develop in an interlaced manner and significantly reducing its strength, thereby directly improving the rock crushing and drilling efficiency of the rotary drilling, reducing drill bit wear, and lowering mining costs. On the other hand, the supercritical carbon dioxide after crushing the rock can also cool the drill bit, thereby protecting the drill bit from damage by high temperature and increasing the life of the drill bit. In addition, the carbon dioxide can also suspend and carry rock cuttings to stabilize the well wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A schematic structural diagram of a geothermal drilling device for carbon dioxide jet rotary drilling provided by the present invention;

[0026] Figure 2 Schematic diagram of the cross-sectional structure of the drill rod in the present invention;

[0027] Figure 3 Schematic diagram of the cross-sectional structure of the connector in the present invention;

[0028] Figure 4 Schematic diagram of the cross-sectional structure of the drill bit of the present invention;

[0029] Figure 5 Schematic diagram of the side structure of the drill bit of the present invention;

[0030] Figure 6 A schematic flow chart of the geothermal drilling method using carbon dioxide jet rotary drilling provided by the present invention.

[0031] In the figure: 1-drilling tower, 2-control center, 3-control valve, 4-drilling rig, 5-dry ice grinding machine, 6-heating pressurizer, 7-mud pump, 8-mud pool, 9-annular space, 10-jet channel, 11-drilling fluid channel, 12-well wall, 13-broken rock formation, 14-connecting flange, 15-shock absorber, 16-drill pipe inner tube, 17-drill pipe spring, 18-clamp joint, 19-clamping part, 20-nozzle, 21-filter screen, 22-carbide blade, 23-flushing fluid outlet, 24-jet outlet, 25-drill bit, 26-drill pipe, 27-connector, 28-connector inner tube, 29-connector outer tube, 30-drill pipe outer tube, 31-carbide blade, 32-sliding part, 33-spring seat. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] The purpose of the present invention is to provide a geothermal drilling device and method for carbon dioxide jet rotary drilling to solve the problems existing in the prior art, thereby reducing drill bit wear, improving drilling efficiency and reducing production costs.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] like Figures 1-6 As shown, this embodiment provides a geothermal drilling device for carbon dioxide jet rotary drilling, including a drilling system, the drilling system including a drill bit 25, a drill rod 26, a drilling rig 4, a drilling tower 1 and a mud pump 7, and also includes a jet system, the jet system including a dry ice abrasive machine 5, a control valve 3, a heating and pressurizing device 6 and a control center 2;

[0036] The drilling end of the drill bit 25 is provided with a flushing fluid inlet 23 and a jet inlet 24. A drilling fluid channel 11 and a jet channel 10 are provided inside the drill bit 25, respectively communicating with the flushing fluid inlet 23 and the jet inlet 24. The drill bit 25 is connected to the drill pipe 26 via a connector 27. The connector 27 includes an inner connector tube 28 and an outer connector tube 29. The drill pipe 26 includes an inner drill pipe tube 16 and an outer drill pipe tube 30. The drilling fluid channel 11 communicates with the inner and outer drill pipe tubes of the drill pipe 26 through the gap between the inner and outer tubes of the connector 27. The jet channel 10 communicates with the inner drill pipe tube 16 through the inner connector tube 28.

[0037] The dry ice abrasive machine 5 is connected to the heating and pressurizing device 6 and communicates with the drill pipe inner tube 16 through the heating and pressurizing device 6. The mud pump 7 is connected to the heating and pressurizing device 6 and communicates with the inner and outer tube gaps of the drill pipe 26 through the heating and pressurizing device 6. The control valve 3 is provided on the pipeline connecting the heating and pressurizing device 6 and the drill pipe inner tube 16.

[0038] The control valve 3 , the mud pump 7 , the drilling rig 4 , the dry ice grinding machine 5 and the temperature increasing and pressurizing device 6 are electrically connected to the control center 2 respectively.

[0039] The present device can generate high-pressure supercritical carbon dioxide during rotary drilling by controlling the dry ice grinder 5 and the heating and pressurizing device 6 through the control center 2. The high-pressure supercritical carbon dioxide is then ejected from the jet nozzle 24 through the drill pipe inner tube 16 and the internal jet channel 10 of the drill bit 25, thereby crushing the rock at the bottom of the hole and forming a crushed rock layer 13 at the bottom of the hole. This accelerates drilling efficiency, reduces drill bit wear, reduces energy consumption, and lowers production costs. Furthermore, since a dedicated pipeline is designed for the jet, the jet does not affect the circulation of the drilling fluid during the jet process, which is of great significance for stabilizing the wellbore, removing rock cuttings at the bottom of the hole, and lubricating and cooling the drill bit. Using a carbon dioxide jet is more efficient and environmentally friendly. The efficiency of a carbon dioxide jet is far higher than that of a water jet or a nitrogen jet, significantly reducing resource consumption. The carbon dioxide generated by the jet is not only environmentally friendly and does not react with the drilling fluid or the formation, but also has the effect of cleaning and cooling the drill bit, stabilizing the wellbore wall, and preventing excessive temperatures from causing the drill bit to become scrapped. Furthermore, the device can be well utilized in other fields such as geological exploration and petroleum exploration.

[0040] In this embodiment, the drill bit 25 is a cemented carbide full-drilling drill bit. The drilling end of the drill bit 25 is provided with three cemented carbide blades 31. The three cemented carbide blades 31 are evenly arranged at 120° intervals from each other. Each cemented carbide blade 31 is provided with multiple evenly distributed cemented carbide blades 22 for cutting rocks.

[0041] In this embodiment, a flushing fluid inlet 23 is provided between each adjacent carbide blade 31, and a jet inlet 24 is disposed in the middle of the drill bit 25. The gap between the inner and outer tubes of the drill bit 25 forms the drilling fluid channel 11, and the inner cavity of the inner tube of the drill bit 25 forms the jet channel 10. The multi-inlet carbide drill bit in this embodiment features a simple structure, rational design, ease of use, and low cost. It can be adjusted to select whether to perform jetting according to actual working conditions. Furthermore, the jet inlet 24 and the flushing fluid inlet 23 are independent of each other and do not affect each other, effectively reducing the impact of drilling fluid on rock breaking by jetting.

[0042] In this embodiment, a nozzle 20 is provided between the jet channel 10 and the jet outlet 24, and a filter 21 is provided between the nozzle 20 and the jet outlet 24. High-pressure supercritical carbon dioxide fluid can be ejected through the nozzle 20 to form a high-pressure jet, and the filter 21 plays a role in filtering the fluid.

[0043] In this embodiment, the lower ends of the connector inner tube 28 and the connector outer tube 29 are each provided with internal threads for threaded connection with the inner tube and outer tube of the drill bit 25, respectively. The upper end of the connector outer tube 29 is provided with internal threads for threaded connection with the lower end of the drill pipe outer tube 30. A clamping member 19 is provided within the upper end of the connector inner tube 28, and a clamping joint 18 is provided within the lower end of the drill pipe inner tube 16 to cooperate with the clamping member 19. The clamping joint 18 and the clamping member 19 are engaged and engaged to connect the connector inner tube 28 and the drill pipe inner tube 16. The threaded connection method is convenient and quick to install. The clamping connection method of the clamping member 19 and the clamping joint 18 facilitates the simultaneous clamping connection of the connector inner tube 28 and the drill pipe inner tube 16 when the connector outer tube 29 and the drill pipe outer tube 30 are threadedly connected. Among them, the clamping joint 18 is a conical head, and the clamping part 19 includes two clamping rods connected by a rotating shaft. A clamping protrusion is provided at one end of the clamping rod close to the clamping joint 18, and a torsion spring is provided at the rotating shaft. After the clamping joint 18 is inserted between the two clamping rods, under the action of the torsion spring, the two clamping rods close and clamp the clamping joint 18 through the clamping protrusion at their ends, thereby realizing the clamping connection between the connector inner tube 28 and the drill pipe inner tube 16.

[0044] In this embodiment, the drill pipe outer tube 30 is provided with a sliding portion 32 near its lower threaded end. A drill pipe spring 17 and two spring seats 33 are mounted on the sliding portion 32. The drill pipe spring 17 is positioned between the two spring seats 33, and the spring seats 33 are capable of sliding axially along the sliding portion 32. A connecting flange 14 is provided at the upper end of the drill pipe outer tube 30, along with a shock absorber 15. The drill pipe spring 17 and spring seats 33 reduce inertial impact on the drill pipe during lifting and lowering operations, and also provide buffering and protection for components such as the lifter, wire rope, and main winch. The connecting flange 14 at the upper end of the drill pipe outer tube 30 is used to connect to other drill pipe sections above it. The provision of the shock absorber 15 reduces shaking and vibration of the drill pipe 26 during drilling, thereby stabilizing the drilling tool.

[0045] A geothermal drilling method using carbon dioxide jet rotary drilling is based on the geothermal drilling device using carbon dioxide jet rotary drilling described above, comprising the following steps:

[0046] S1: Determine the borehole to be tested, install the drilling tower 1, drilling rig 4, and control center 2, excavate the mud pit 8, arrange the mud pump 7, and then install the dry ice grinder 5 and the heating and pressurizing device 6; use pipelines to connect the mud pump 7 and the dry ice grinder 5 to the heating and pressurizing device 6, and use concentric pipelines to connect the heating and pressurizing device 6 to the drill pipe inner tube 16 and the drill pipe outer tube 30, so that the pressurized carbon dioxide and drilling fluid can flow into the inner and outer tube gaps of the drill pipe inner tube 16 and the drill pipe 26 respectively, and install a control valve 3 between the drill pipe inner tube 16 and the inner tube of the concentric pipeline;

[0047] S2: Connect the drill bit 25 to the connector 27, and install the connector 27 on the drill rod 26. Install the drill rod 26 on the drilling rig 4 and hang it on the drilling tower 1.

[0048] S3: Start the mud pump 7 to circulate the drilling fluid through the gaps between the inner and outer tubes of the drill pipe 26 and the annular space 9 in the borehole. The drill pipe 26 is lowered to the bottom of the hole by operating the winch of the drilling rig 4, and the gyrator of the drilling rig 4 is operated to rotate and break the rock. The annular space 9 refers to the annular gap formed between the wellbore 12, the drill pipe 26, and the drill bit 25.

[0049] S4: The dry ice grinding machine 5 is started to produce the carbon dioxide required for the jet and transported to the heating and pressurizing device 6; the control valve 3 is opened by the control center 2 to transport the high-pressure carbon dioxide fluid to the inner tube 16 of the drill pipe, and a high-pressure jet is generated at the bottom of the hole to crush the rock. After the rock is crushed for a period of time, the jet operation is stopped and the drilling rig 4 is operated to perform rotary drilling;

[0050] S5: Repeat step S4 to repeatedly perform carbon dioxide jet rotary drilling.

[0051] During drilling, the jet intensity and interval are adjusted by control center 2 based on the properties of the rock at the bottom of the hole. Control center 2 can also use control valve 3 to adjust the flow of drilling fluid and CO2 based on the actual conditions at the bottom of the hole, thus achieving a jet-drilling cycle, improving drilling efficiency and reducing CO2 usage.

[0052] In step S1 , a mud pool 8 is excavated near a water source and a borehole, and a mud pump 7 is arranged beside the pool.

[0053] The supercritical carbon dioxide jet employed in this invention offers advantages over other jets. Compared to water jets, it has lower nozzle pressure energy loss and a higher thermal cracking effect. Compared to nitrogen jets, it has higher jet impact shear force, erosion force, and thermal cracking effect. Furthermore, the carbon dioxide generated by the jet can flush and cool the drill bit, reducing damage to the drill bit from rock cuttings and extending its lifespan.

[0054] The present invention designs a concentric tube drilling tool and sets a jet channel inside the drilling tool, which can perform jet work while using drilling fluid circulation, thereby solving the problem of shallow application depth; and the jet medium is not limited to carbon dioxide and can be replaced by connecting other instruments and equipment, making the device more flexible.

[0055] The present invention adopts a periodic adjustment working mode. According to the actual drilling situation at the bottom of the hole, the control center adjusts the jet intensity and interval at regular intervals to meet the actual engineering use needs as much as possible and improve work efficiency; it can also minimize the consumption of jets and reduce resource loss.

[0056] The present invention is suitable for hot dry rock mining. It can not only solve the problem that hot dry rock is hard and difficult to mine, but also solve the problem of excessively high mining environment temperature, thereby improving mining efficiency, reducing mining costs, and enhancing the feasibility of hot dry rock development.

[0057] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A geothermal drilling device for carbon dioxide jet rotary drilling, comprising a drilling system, wherein the drilling system comprises a drill bit, a drill pipe, a drilling rig, a drilling tower, and a mud pump, characterized in that: Also included is a fluidic system comprising a dry ice grinder, a control valve, a temperature booster and a control center; The drilling end of the drill bit is provided with a flushing liquid inlet and a jet water inlet, and the drill bit is provided with a drilling fluid channel and a jet channel respectively connected to the flushing liquid inlet and the jet water inlet. The drill bit is connected to the drill pipe via a connector; the connector includes a connector inner tube and a connector outer tube, and the drill pipe includes a drill pipe inner tube and a drill pipe outer tube. The drilling fluid channel is connected to the inner and outer tube gaps of the drill pipe through the inner and outer tube gaps of the connector, and the jet channel is connected to the inner pipe of the drill pipe through the connector inner tube. The dry ice abrasive machine is connected to the heating and pressurizing device and communicates with the inner tube of the drill pipe through the heating and pressurizing device. The mud pump is connected to the heating and pressurizing device and communicates with the inner and outer tube gaps of the drill pipe through the heating and pressurizing device. The control valve is provided on the pipeline connecting the heating and pressurizing device and the inner tube of the drill pipe. The control valve, the mud pump, the drilling rig, the dry ice grinding machine and the temperature increasing and pressurizing device are electrically connected to the control center respectively; During the rotary drilling process, the control center controls the dry ice grinder and the temperature booster to generate high-pressure supercritical carbon dioxide, which is emitted from the jet nozzle through the inner tube of the drill pipe and the jet channel inside the drill bit.

2. The geothermal drilling device for carbon dioxide jet rotary drilling according to claim 1, characterized in that: The drill bit is a cemented carbide full-drilling drill bit. The drilling end of the drill bit is provided with three cemented carbide blades, and each of the cemented carbide blades is provided with a plurality of evenly distributed cemented carbide blades.

3. The geothermal drilling device for carbon dioxide jet rotary drilling according to claim 2, characterized in that: A flushing fluid outlet is provided between each adjacent two carbide blades, the jet outlet is provided in the middle of the drill bit, the gap between the inner and outer tubes of the drill bit constitutes the drilling fluid channel, and the inner cavity of the inner tube of the drill bit constitutes the jet channel.

4. The geothermal drilling device for carbon dioxide jet rotary drilling according to claim 1, characterized in that: A nozzle is provided between the jet channel and the jet water outlet, and a filter is provided between the nozzle and the jet water outlet.

5. The geothermal drilling device for carbon dioxide jet rotary drilling according to claim 3, characterized in that: The lower ends of the connector inner tube and the connector outer tube are both provided with internal threads, which are used to be threadedly connected to the inner tube and outer tube of the drill bit, respectively. The upper end of the connector outer tube is provided with an internal thread, which is used to be threadedly connected to the lower end of the drill pipe outer tube. A clamping piece is provided inside the upper end of the connector inner tube, and a clamping joint that cooperates with the clamping piece is provided inside the lower end of the drill pipe inner tube. The clamping joint cooperates with the clamping piece to connect the connector inner tube and the drill pipe inner tube.

6. The geothermal drilling device for carbon dioxide jet rotary drilling according to claim 5, characterized in that: The drill rod outer tube is provided with a sliding portion near the thread at its lower end, and a drill rod spring and two spring seats are sleeved on the sliding portion. The drill rod spring is arranged between the two spring seats, and the spring seat can slide axially along the sliding portion. The upper end of the drill rod outer tube is provided with a connecting flange, and the upper end of the drill rod outer tube is also provided with a shock absorber.

7. A geothermal drilling method using carbon dioxide jet rotary drilling, characterized in that: The geothermal drilling device for carbon dioxide jet rotary drilling according to any one of claims 1 to 6 comprises the following steps: S1: Determine the borehole to be tested, install the drilling tower, the drilling rig, and the control center, excavate a mud pit, arrange the mud pump, and then install the dry ice grinder and the temperature-boosting pressurizer; connect the mud pump and the dry ice grinder to the temperature-boosting pressurizer using pipelines, and connect the temperature-boosting pressurizer to the drill pipe inner tube and the drill pipe outer tube using concentric pipelines, so that pressurized carbon dioxide and drilling fluid can flow into the drill pipe inner tube and the gap between the inner and outer tubes of the drill pipe, respectively, and install the control valve between the drill pipe inner tube and the inner tube of the concentric pipeline; S2: Connecting the drill bit to the connector, installing the connector on the drill rod, installing the drill rod on the drilling rig and hanging it on the drilling tower; S3: starting the mud pump to circulate the drilling fluid through the gap between the inner and outer tubes of the drill pipe and the annular space in the borehole, operating the winch of the drilling rig to lower the drill pipe to the bottom of the hole, and operating the rotator of the drilling rig to rotate and break the rock; S4: The dry ice grinding machine is started to produce carbon dioxide required for the jet, and the carbon dioxide is transported to the heating and pressurizing device; the control valve is opened by the control center to transport the high-pressure carbon dioxide fluid to the inner tube of the drill pipe, and a high-pressure jet is generated at the bottom of the hole to crush the rock. After the rock is crushed for a period of time, the jet is stopped and the drilling rig is operated to perform rotary drilling; S5: Repeat step S4 to repeatedly perform carbon dioxide jet rotary drilling.

8. The geothermal drilling method using carbon dioxide jet rotary drilling according to claim 7, characterized in that: During the drilling process, the jet intensity and interval are adjusted by the control center according to the properties of the rock at the bottom of the hole.

9. The geothermal drilling method using carbon dioxide jet rotary drilling according to claim 7, characterized in that: In step S1, a mud pool is excavated near a water source and a borehole, and the mud pump is arranged beside the pool.

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