CN118008186A - Fishing device and fishing method for broken drill bit in geothermal well drilling process - Google Patents

Abstract

The invention relates to a salvaging device and a salvaging method after a drill bit is disassembled in the geothermal well drilling process, and belongs to the technical field of drill bit salvaging; the device comprises a driving assembly, a salvaging main body and a lifting boss, wherein the driving assembly is arranged at a wellhead of a geothermal well, the salvaging main body is positioned in the geothermal well, the salvaging main body is connected with the driving assembly through a lifting sling and a loop bar, the driving assembly controls the salvaging main body to lift through the lifting sling, and the driving assembly controls the salvaging main body to rotate through the loop bar; three lifting bosses in circular array are arranged in the salvage main body, each lifting boss is independently connected in the salvage main body in a sliding manner along the vertical direction, a welding cavity with an opening at the lower end is detachably arranged at the lower end of each lifting boss, an inner claw is arranged at the lower end of the welding cavity, a rebounding outer claw is arranged at the outer side of the inner claw, and an electronic spark plug and thermite are arranged in the welding cavity; the problem of the drill bit salvage success rate after having solved the present disintegration lower, unable disposable salvage is solved.

Description

A salvage device and salvage method for a drill bit disintegrated during geothermal well drilling

Technical Field

The invention belongs to the technical field of drill bit salvage, and in particular relates to a salvage device and a salvage method after a drill bit is disintegrated during geothermal well drilling.

Background technique

During the drilling process of geothermal wells, as the drilling depth continues to increase, the rock formations encountered are becoming more and more complex, and there are more and more problems to be faced. Among them, the salvage of the drill bit after disintegration is one of the problems. During the drilling process, when the roller drill bit encounters a broken formation, due to the long-term drilling of the drill bit, it is easy to collapse and disintegrate under high temperature and high pressure and frequent mechanical vibration, and get stuck in the broken formation, and it cannot be removed by lifting the drill rod. At present, there is no specific device that meets the actual operation for salvaging the fallen drill bit. The usual method is to use a wire rope to lower the mechanical device to make it jam the drill bit, and then lift it, or to lower a strong magnet, use magnetic force to attract it, and then lift it. The current commonly used method is difficult to operate and has a small lifting force. When the drill bit collapses and disintegrates, its various parts are firmly stuck in the broken formation. The success rate of salvage is very low by relying on the clamping force of the mechanical device or magnetic force on the drill bit. It is difficult to salvage all the drill bit parts at once, which seriously affects the construction progress.

Summary of the invention

The present invention overcomes the shortcomings of the prior art and provides a salvage device and salvage method for a drill bit that has disintegrated during geothermal well drilling, thereby solving the current problems of low success rate in salvaging a drill bit that has disintegrated and inability to salvage the drill bit in one go.

In order to achieve the above object, the present invention is implemented through the following technical solutions.

A salvage device for after a drill bit is disassembled during the drilling of a geothermal well comprises a driving assembly, a salvage body and a lifting boss. The driving assembly is arranged at the wellhead of the geothermal well, the salvage body is located inside the geothermal well, the salvage body is connected to the driving assembly via a lifting sling and a sleeve rod, the driving assembly controls the lifting and lowering of the salvage body via the lifting sling, and the driving assembly controls the rotation of the salvage body via the sleeve rod; three lifting bosses in a circular array are arranged inside the salvage body, each lifting boss is independently connected to the inside of the salvage body by sliding in a vertical direction, a welding cavity with an opening at the lower end is detachably arranged at the lower end of each lifting boss, an inner clamping claw is arranged at the lower end of the welding cavity, a resilient outer clamping claw is arranged on the outer side of the inner clamping claw, and an electronic spark plug and a thermite are arranged inside the welding cavity.

Furthermore, a ground bracket is provided at the wellhead of the geothermal well, and the driving assembly is provided on the ground bracket.

Furthermore, the salvage body includes a main shaft, a main body cylinder cavity, a sling connecting ring, and boss separating spokes; the main body cylinder cavity is a cylindrical structure with openings at both ends; three circular arrays of sling connecting rings are fixedly arranged on the upper end of the side wall of the main body cylinder cavity, and the lower end of the lifting sling is connected to the sling connecting ring; a main shaft is arranged at the center of the upper end opening of the main body cylinder cavity; three circular arrays of vertical slide grooves are arranged on the outer cylindrical surface of the main shaft.

Furthermore, the upper end of the inner wall of the main cylinder cavity and the lower end of the outer wall of the main shaft are fixedly connected by three circular arrays of boss dividing spokes, and each boss dividing spoke is arranged along the radial direction of the main cylinder cavity; the upper end opening of the main cylinder cavity is divided into three circular arrays of fan-shaped through holes by the three boss dividing spokes, and each slide groove corresponds to a fan-shaped through hole.

Furthermore, a rotating rod is fixedly provided at the upper end of the side wall of the main shaft, the lower end of the sleeve rod is fixedly inserted into the rotating rod, and the upper end of the sleeve rod is connected to the driving assembly; the sleeve rod, rotating rod and main shaft are all cylindrical structures with openings at both ends, and the cable passes downward through the sleeve rod, rotating rod, main shaft and three lifting bosses in turn and is connected to the electronic spark plugs inside the three welding cavities respectively.

Furthermore, a lifting boss is arranged inside each fan-shaped through hole of the main body cylinder cavity, and the three lifting bosses have the same structure; the lifting boss includes a boss body, a slider, and a connecting seat, the boss body is a fan-shaped block structure, and the horizontal cross-section of the boss body is fan-shaped, and a vertical slider is fixedly arranged in the middle of the inner arc-shaped edge of the upper end face of the boss body, and the slider slides along the vertical direction and is clamped in the corresponding slide groove.

Furthermore, the connecting seat is fixedly provided at the lower end surface of the boss body, the connecting seat is a fan-shaped block structure, the horizontal cross-section of the connecting seat is fan-shaped, and the welding cavity is detachably provided at the lower end surface of the connecting seat, the welding cavity is a fan-shaped cylindrical structure surrounded by an inner circular arc side wall, an outer circular arc side wall, and rectangular plane side walls on both sides.

Furthermore, a row of inner claws are arranged on the lower end surface of the outer arc-shaped side wall of the welding cavity; a row of outer claws are arranged on the lower end surface of the boss body on the outer side of the connecting seat, and the outer claws are vertically arranged wedge-shaped plate structures, and the width of the lower end of the outer claws is smaller than the width of the upper end of the outer claws, and the upper end of the outer claws extends to the outside of the boss body, and a hook is fixedly arranged on the inner side of the lower end of the outer claw, and the tip of the hook is facing the axis of the main body cylinder cavity; the outer claws are made of stainless steel material, and the outer claws are elastic and can expand outward to undergo elastic deformation.

Furthermore, the thermite is a mixture of aluminum powder, ferrosoferric oxide and a combustion aid.

A method for salvaging a salvaging device after a drill bit disintegrates during geothermal well drilling, comprising the following steps:

Step 1: First determine the relative position of the broken strata that the drill bit is stuck to at the bottom of the geothermal well after it breaks apart and decomposes;

Step 2: Install the welding cavity on the lifting boss, install the three lifting bosses on the salvage body respectively, connect the sleeve rod to the salvage body and the driving assembly respectively, and connect the salvage body to the driving assembly through the lifting sling;

Step 3: lower the salvage body through the driving assembly, and control the salvage body to rotate through the driving assembly until the outer claws and the inner claws contact the various decomposed parts of the drill bit;

Step 4: Continue to lower the salvage body through the driving assembly. Under the deadweight of the whole device and the lifting sling, the outer claws expand outward and undergo elastic deformation. The hooks at the lower ends of the outer claws are embedded in the gap between the drill bit and the formation, thereby clamping the disassembled drill bit.

Step 5: The electronic spark plug is energized through the cable, and the inside of the welding cavity begins to undergo thermite reaction. During the thermite reaction, on the one hand, molten iron is formed, which is filled into the welding cavity and into the enclosed space of the rock layer at the upper end, side, and bottom of the drill bit. Since rock is a poor conductor of heat, the molten iron is filled into the gap between the drill bit and the rock layer. After the molten iron is cooled, the whole device is welded to the decomposed drill bit to form a permanent joint with a firm bond. On the other hand, a large amount of heat is released during the thermite reaction, causing the rock outside the drill bit and the rock cuttings inside the drill bit to begin to melt and crack, and the rock layer where the drill bit is located begins to loosen, causing the decomposed drill bit to loosen in the rock layer, making it easier to pull out the decomposed drill bit.

Step 6: The driving assembly is raised as a whole through the lifting sling control device. Since the device as a whole forms a firmly bonded permanent joint with the disassembled drill bit, the disassembled drill bit can be directly salvaged from the geothermal well; after being salvaged from the well, the welding cavity is removed from the lifting boss.

The beneficial effects of the present invention compared with the prior art are as follows:

Compared with the traditional drill bit salvage device, in addition to the mechanical external and internal clamping forces on the drill bit, the present invention also provides an adhesive force between the device and the drill bit. The adhesive force is relative to the drill bit and will not produce adhesion with the rock formation. When the device is lifted, the rock formation where the drill bit is located and the internal rock cuttings melt, and the rock formation undergoes thermal fracture, making the rock formation in which the drill bit is stuck loose, and the drill bit loosens in the formation, thereby greatly improving the success rate of salvaging the drill bit stuck in the rock formation. In addition, the device adopts thermite welding technology, which is simple and, most importantly, has its own oxygen supply, which is particularly suitable for the low-oxygen environment underground.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described in detail below in conjunction with the accompanying drawings:

FIG1 is a schematic diagram of the overall structure of the present invention;

FIG2 is a schematic diagram of the connection between the salvage body, the lifting boss, and the welding cavity;

FIG3 is a second schematic diagram of the connection between the salvage body, the lifting boss, and the welding cavity;

FIG4 is a third schematic diagram of the connection between the salvage body, the lifting boss, and the welding cavity;

FIG5 is a fourth schematic diagram of the connection between the salvage body, the lifting boss, and the welding cavity;

FIG6 is a schematic structural diagram of a salvage body;

FIG. 7 is a schematic diagram of the connection between the lifting boss and the welding cavity;

FIG8 is a second schematic diagram of the connection between the lifting boss and the welding cavity;

Among them, 1 is a geothermal well, 2 is a ground support, 3 is a driving assembly, 4 is a salvage body, 401 is a main body cylinder cavity, 402 is a main shaft, 403 is a slide groove, 404 is a boss separation spoke, 405 is a sling connecting ring, 5 is a rotating rod, 6 is a sleeve rod, 7 is a lifting sling, 8 is a lifting boss, 801 is a boss body, 802 is a slider, 803 is a fender, 804 is a connecting seat, 9 is a welding cavity, 901 is an inner arc-shaped side wall, 902 is an outer arc-shaped side wall, 903 is a rectangular plane side wall, 904 is an inner claw, 905 is an outer claw, 906 is a hook, 907 is an electronic spark plug, and 10 is a drill bit.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail in conjunction with the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The technical solutions of the present invention are described in detail below in conjunction with the embodiments and the accompanying drawings, but the scope of protection is not limited thereto.

As shown in FIGS. 1-8 , the present invention provides a salvage device after a drill bit is disassembled during geothermal well drilling, comprising a drive assembly 3 , a lifting sling 7 , a sleeve rod 6 , a rotating rod 5 , a salvage body 4 , and a lifting boss 8 .

A ground support 2 is provided at the wellhead of the geothermal well 1 , and a driving assembly 3 is provided on the ground support 2 . The driving assembly 3 is located above the wellhead of the geothermal well 1 .

The salvaging body 4 includes a main shaft 402 , a main body cylinder 401 , a sling connecting ring 405 , and boss separating spokes 404 .

The main body cylinder cavity 401 is a cylindrical structure with openings at both ends. Three circular arrays of sling connection rings 405 are fixedly arranged at the upper end of the side wall of the main body cylinder cavity 401. A main shaft 402 is arranged at the center of the upper end opening of the main body cylinder cavity 401. The main shaft 402 is a cylindrical structure with openings at both ends. The upper end of the main shaft 402 extends to the outer side of the upper end opening of the main body cylinder cavity 401; three circular arrays of slide grooves 403 are arranged on the outer cylindrical surface of the main shaft 402, and the slide grooves 403 are arranged vertically.

The upper end of the inner wall of the main cylinder cavity 401 and the lower end of the outer wall of the main shaft 402 are fixedly connected by three circular arrays of boss separation spokes 404, each boss separation spoke 404 is arranged along the radial direction of the main cylinder cavity 401, the outer end of the boss separation spoke 404 is fixedly connected to the upper end of the inner wall of the main cylinder cavity 401, and the inner end of the boss separation spoke 404 is fixedly connected to the lower end of the outer wall of the main shaft 402; the upper end opening of the main cylinder cavity 401 is divided into three circular arrays of fan-shaped through holes by the three boss separation spokes 404, each slide groove 403 is located in the middle of two adjacent boss separation spokes 404, and each slide groove 403 corresponds to a fan-shaped through hole.

A rotating rod 5 is fixedly arranged at the upper end of the side wall of the main shaft 402. The rotating rod 5 is a cylindrical structure with openings at both ends. The internal space of the rotating rod 5 is connected to the internal space of the main shaft 402. The sleeve rod 6 is a hollow rod-shaped structure with openings at both ends. The lower end of the sleeve rod 6 is inserted into the rotating rod 5 and fixedly connected to the rotating rod 5. The internal space of the sleeve rod 6 is connected to the internal space of the main shaft 402. The sleeve rod 6 drives the rotating rod 5 and the salvage body 4 to rotate synchronously.

The driving assembly 3 is fixedly connected to the three lifting ropes 405 at the upper end of the main body cylinder cavity 401 through the three lifting ropes 7. The driving assembly 3 controls the lifting of the entire device through the three lifting ropes 7.

The upper end of the sleeve rod 6 is connected to the driving assembly 3, and the driving assembly 3 drives the sleeve rod 6 to rotate, and the sleeve rod 6 drives the rotating rod 5 and the salvage body 4 to rotate synchronously.

A lifting boss 8 is arranged inside each sector-shaped through hole of the main body cylinder cavity 401, and the three lifting bosses 8 have the same structure and are arranged in a circular array. The lifting boss 8 includes a boss body 801, a slider 802, a fender 803, a connecting seat 804, a welding cavity 9, an electronic spark plug 907, an inner claw 904, and an outer claw 905.

The boss body 801 is a fan-shaped block structure, and the horizontal cross section of the boss body 801 is fan-shaped, that is, the boss body 801 is a block structure surrounded by a horizontal fan-shaped plane at the upper end, a horizontal fan-shaped plane at the lower end, vertical rectangular planes at both sides, an outer arc surface, and an inner arc surface. The upper end of each boss body 801 extends from the corresponding fan-shaped through hole to the outer side of the upper end opening of the main body barrel cavity 401, and the inner arc surface of the boss body 801 fits with the outer cylindrical surface of the main shaft 402, and the outer arc surface of the boss body 801 fits with the inner cylindrical surface of the main body barrel cavity 401.

A vertical slider 802 is fixedly provided in the middle of the inner arc edge of the upper end face of the boss body 801. The slider 802 extends to the outside of the inner arc surface of the boss body 801, and the slider 802 slides along the vertical direction and is engaged with the corresponding slide groove 403. The outer side surfaces of the slider 802 are respectively fitted with the inner walls of the slide groove 403, so that the boss body 801 can only be raised and lowered relative to the main shaft 402, but cannot be rotated relative to the main shaft 402.

A fender 803 is provided on the side of the outer arc surface of the slider 802 close to the boss body 801, and the fender 803 is fixedly provided on the upper end surface of the boss body 801. The fender 803 is an arc-shaped plate structure, and the axis of the fender 803 coincides with the axis of the boss body 801. The slider 802 is located on the inner side of the fender 803, and the fender 803 protects the slider 802.

A connection seat 804 is fixedly provided at the lower end surface of the boss body 801. The connection seat 804 is a fan-shaped block structure. The horizontal cross section of the connection seat 804 is fan-shaped, that is, the connection seat 804 is a block structure surrounded by a horizontal fan-shaped plane at the upper end, a horizontal fan-shaped plane at the lower end, vertical rectangular planes at both sides, an outer arc surface, and an inner arc surface. The vertical rectangular planes at both sides of the connection seat 804 coincide with the vertical rectangular planes at both sides of the boss body 801. The inner arc surface of the connection seat 804 is located on the inner side of the inner arc surface of the boss body 801, and the outer arc surface of the connection seat 804 is located on the inner side of the outer arc surface of the boss body 801.

A welding cavity 9 with an opening at the lower end is detachably provided at the lower end surface of the connection seat 804. The welding cavity 9 is a fan-shaped cylindrical structure surrounded by an inner arc-shaped side wall 901, an outer arc-shaped side wall 902, and rectangular plane side walls 903 on both sides. The outer side surface of the outer arc-shaped side wall 902 of the welding cavity 9 coincides with the outer arc surface of the connection seat 804, the outer side surface of the inner arc-shaped side wall 901 of the welding cavity 9 coincides with the inner arc surface of the connection seat 804, and the outer side surfaces of the rectangular plane side walls 903 on both sides of the welding cavity 9 are located on the inner side of the vertical rectangular planes on both sides of the connection seat 804. A row of inner clamping claws 904 are provided on the lower end surface of the outer arc-shaped side wall 902 of the welding cavity 9. The inner clamping claws 904 are made of high-strength, high-toughness, high-melting-point alloy steel and are not prone to elastic deformation.

A row of outer claws 905 are arranged at the lower end surface of the boss body 801 outside the connection seat 804. The outer claws 905 are vertically arranged wedge-shaped plate structures. The width of the lower end of the outer claws 905 is smaller than the width of the upper end of the outer claws 905. The upper end of the outer claws 905 extends to the outside of the boss body 801. A hook 906 is fixedly arranged on the inner side of the lower end of the outer claw 905. The tip of the hook 906 faces the axis of the main body cylinder cavity 401. The outer claws 905 are made of stainless steel material. The outer claws 905 are elastic and can expand outward to undergo elastic deformation.

An electronic spark plug 907 is fixedly arranged on the inner top surface of the welding cavity 9.

A cable is inserted into the sleeve rod 6, and the cable passes downward through the sleeve rod 6, the rotating rod 5, the main shaft 402, the three boss bodies 801, and the three connecting seats 804, and is respectively connected to the electronic spark plugs 907 inside the three welding cavities 9. When the electronic spark plugs 907 are energized through the cable, high temperature will be generated instantly.

Thermite is arranged inside each welding cavity 9. The thermite is a mixture of aluminum powder, ferrosoferric oxide and barium peroxide as a combustion aid for generating thermite reaction.

The inner clamping claw 904 cooperates with the welding cavity 9 to increase the bonding area with the drill bit 10, and cooperates with the outer clamping claw 905 to improve the success rate of salvaging the drill bit 10 after disassembly.

The present invention provides a salvaging method for a salvaging device after a drill bit is disintegrated during geothermal well drilling, which comprises:

The first step: first determine the relative position of the broken stratum that the drill bit 10 is stuck to at the bottom of the geothermal well 1 after it is broken and decomposed.

Step 2: Fix the ground bracket 2 to the wellhead of the geothermal well 1, install the welding cavity 9 on the lifting boss 8, install the three lifting bosses 8 on the salvage body 4 respectively, connect the sleeve rod 6 to the salvage body 4 and the driving assembly 3 respectively, and connect the salvage body 4 to the driving assembly 3 through the lifting sling 7.

Step 3: lower the salvage body 4 through the driving assembly 3 , and control the salvage body 4 to rotate through the driving assembly 3 until the outer claws 905 and the inner claws 904 contact the various decomposed parts of the drill bit 10 .

Since each lifting boss 8 is slidably connected to the main shaft 402 of the salvage body 4 through an independent slider 802, the three lifting bosses 8 can be independently lifted to adjust the height of each lifting boss 8, so that the outer claw 905 and the inner claw 904 at the lower end of each lifting boss 8 can contact the drill bit 10 at different positions.

Step 4: Continue to lower the salvage body 4 through the driving assembly 3. Under the action of the deadweight of the entire device and the lifting sling 7, the outer claw 905 expands outward and undergoes elastic deformation. The hook 906 at the lower end of the outer claw 905 is embedded in the gap between the drill bit 10 and the formation, thereby clamping the disassembled drill bit 10.

Step 5: The electronic spark plug 907 is energized through the cable, and the inside of the welding cavity 9 begins to undergo thermite reaction. During the thermite reaction, on the one hand, molten iron is formed, and the molten iron is filled into the welding cavity 9 and into the enclosed space of the rock layer at the upper end, side, and bottom of the drill bit 10. Since rock is a poor conductor of heat, the molten iron is filled into the gap between the drill bit 10 and the rock layer. After the molten iron is cooled, the entire device is welded to the decomposed drill bit 10 to form a firmly bonded permanent joint. On the other hand, a large amount of heat is released during the thermite reaction, causing the rock outside the drill bit 10 and the rock cuttings inside the drill bit 10 to begin to melt and crack, and the rock layer where the drill bit 10 is located begins to loosen, causing the decomposed drill bit 10 to loosen in the rock layer, making it easier to pull out the decomposed drill bit 10.

Welding by thermite reaction is called aluminothermic welding. The principle of aluminothermic welding is to mix aluminum powder with ferroferric oxide in a ratio of 1:3, and add an appropriate amount of barium peroxide as a combustion aid. When it is decomposed by heat, it releases oxygen, making the reaction more intense. Thermite reacts as follows: 8Al+3Fe ₃ O ₄ =4Al ₂ O ₃ +9Fe+795 kcal heat.

Step 6: The driving assembly 3 controls the device to rise as a whole through the lifting sling 7. Since the device as a whole forms a permanent joint with the disassembled drill bit 10, the disassembled drill bit 10 can be directly salvaged from the geothermal well 1. After being salvaged from the well, the welding cavity 9 is removed from the lifting boss 8.

It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims (10)

1. A salvage device after a drill bit is disassembled during the drilling process of a geothermal well, characterized in that it comprises a driving component (3), a salvage body (4), and a lifting boss (8), wherein the driving component (3) is arranged at the wellhead of the geothermal well (1), the salvage body (4) is located inside the geothermal well (1), the salvage body (4) is connected to the driving component (3) via a lifting sling (7) and a sleeve rod (6), the driving component (3) controls the lifting of the salvage body (4) via the lifting sling (7), and the driving component (3) controls the lifting of the salvage body (4) via the sleeve rod (6) (4) for rotation; three circular array lifting bosses (8) are arranged inside the salvage body (4); each lifting boss (8) is independently connected to the inside of the salvage body (4) by sliding in the vertical direction; a welding cavity (9) with an opening at the lower end is detachably arranged at the lower end of each lifting boss (8); an inner clamping claw (904) is arranged at the lower end of the welding cavity (9); a resilient outer clamping claw (905) is arranged outside the inner clamping claw (904); an electronic spark plug (907) and a thermite are arranged inside the welding cavity (9). 2. A salvage device after a drill bit is disintegrated during geothermal well drilling according to claim 1, characterized in that a ground bracket (2) is arranged at the wellhead of the geothermal well (1), and the driving assembly (3) is arranged on the ground bracket (2). 3. A salvage device after the drill bit is disassembled during the geothermal well drilling process according to claim 1, characterized in that: the salvage body (4) comprises a main shaft (402), a main body cylinder (401), a sling connecting ring (405), and boss separation spokes (404); The main body cylinder cavity (401) is a cylindrical structure with openings at both ends; three circular arrays of sling connection rings (405) are fixedly arranged at the upper end of the side wall of the main body cylinder cavity (401), and the lower end of the lifting sling (7) is connected to the sling connection ring (405); a main shaft (402) is arranged at the center of the upper end opening of the main body cylinder cavity (401); and three circular arrays of vertical sliding grooves (403) are arranged on the outer cylindrical surface of the main shaft (402). 4. A salvage device after the drill bit is disassembled during the geothermal well drilling process according to claim 3, characterized in that: the upper end of the inner wall of the main barrel cavity (401) and the lower end of the outer wall of the main shaft (402) are fixedly connected by three circular arrays of boss separation spokes (404), and each boss separation spoke (404) is arranged along the radial direction of the main barrel cavity (401); the upper end opening of the main barrel cavity (401) is divided into three circular arrays of fan-shaped through holes by the three boss separation spokes (404), and each slide groove (403) corresponds to a fan-shaped through hole. 5. A salvage device after the drill bit is disassembled during the drilling of a geothermal well according to claim 4, characterized in that: a rotating rod (5) is fixedly arranged at the upper end of the side wall of the main shaft (402), the lower end of the sleeve rod (6) is fixedly inserted into the rotating rod (5), and the upper end of the sleeve rod (6) is connected to the driving component (3); the sleeve rod (6), the rotating rod (5), and the main shaft (402) are all cylindrical structures with openings at both ends, and the cable passes downward through the sleeve rod (6), the rotating rod (5), the main shaft (402), and the three lifting bosses (8) in turn, and is respectively connected to the electronic spark plugs (907) inside the three welding cavities (9). 6. A salvage device after the drill bit is disassembled during the geothermal well drilling process according to claim 5, characterized in that: a lifting boss (8) is arranged inside each fan-shaped through hole of the main body barrel cavity (401), and the three lifting bosses (8) have the same structure; the lifting boss (8) includes a boss body (801), a slider (802), and a connecting seat (804), the boss body (801) is a fan-shaped block structure, and the horizontal cross-section of the boss body (801) is fan-shaped, and a vertical slider (802) is fixedly arranged in the middle of the inner arc edge of the upper end surface of the boss body (801), and the slider (802) slides along the vertical direction and is engaged with the corresponding slide groove (403). 7. A salvage device after the drill bit is disassembled during the drilling of a geothermal well according to claim 6, characterized in that: the connecting seat (804) is fixedly arranged at the lower end surface of the boss body (801), the connecting seat (804) is a fan-shaped block structure, the horizontal cross-section of the connecting seat (804) is fan-shaped, and the welding cavity (9) is detachably arranged at the lower end surface of the connecting seat (804), and the welding cavity (9) is a fan-shaped cylindrical structure surrounded by an inner arc-shaped side wall (901), an outer arc-shaped side wall (902), and rectangular plane side walls (903) on both sides. 8. A salvage device for a drill bit after it is disassembled during the drilling of a geothermal well according to claim 7, characterized in that: a row of inner claws (904) are arranged on the lower end surface of the outer arc-shaped side wall (902) of the welding cavity (9); a row of outer claws (905) are arranged on the lower end surface of the boss body (801) outside the connecting seat (804), the outer claws (905) are vertically arranged wedge-shaped plate structures, the width of the lower end of the outer claws (905) is smaller than the width of the upper end of the outer claws (905), the upper end of the outer claws (905) extends to the outside of the boss body (801), and a hook (906) is fixedly arranged on the inner side of the lower end of the outer claw (905), and the tip of the hook (906) faces the axis of the main barrel cavity (401); the outer claws (905) are made of stainless steel, and the outer claws (905) are elastic and can expand outward to undergo elastic deformation. 9. The salvage device after the drill bit disintegrates during the geothermal well drilling process according to claim 1, characterized in that the thermite is a mixture of aluminum powder, ferrosoferric oxide and a combustion aid. 10. The method for salvaging a salvaging device after a drill bit is disassembled during geothermal well drilling according to claim 8, characterized in that it comprises the following steps: The first step is to first determine the relative position of the broken strata at the bottom of the geothermal well (1) after the drill bit (10) is broken and decomposed and stuck; Step 2: Install the welding cavity (9) on the lifting boss (8), install the three lifting bosses (8) on the salvage body (4), connect the sleeve rod (6) to the salvage body (4) and the drive assembly (3), respectively, and connect the salvage body (4) to the drive assembly (3) via the lifting sling (7); Step 3: lowering the salvage body (4) through the driving assembly (3), and controlling the salvage body (4) to rotate through the driving assembly (3) until the outer clamping claw (905) and the inner clamping claw (904) contact the various decomposed parts of the drill bit (10); Step 4: The salvaging body (4) is further lowered through the driving assembly (3). Under the deadweight of the entire device and the lifting sling (7), the outer clamping claw (905) expands outward and undergoes elastic deformation. The hook (906) at the lower end of the outer clamping claw (905) is embedded in the gap between the drill bit (10) and the formation, thereby clamping the disassembled drill bit (10); Step 5: The electronic spark plug (907) is energized through the cable, and the inside of the welding cavity (9) begins to undergo an aluminothermic reaction. During the aluminothermic reaction, molten iron is formed, which is filled into the welding cavity (9) and into the enclosed space of the rock layer at the top, side, and bottom of the drill bit (10). Since rock is a poor conductor of heat, the molten iron is filled into the gap between the drill bit (10) and the rock layer. After the molten iron cools down, the entire device is welded to the decomposed drill bit (10) to form a firmly bonded permanent joint. On the other hand, a large amount of heat is released during the aluminothermic reaction, causing the rock outside the drill bit (10) and the rock cuttings inside the drill bit (10) to begin to melt and crack, and the rock layer where the drill bit (10) is located begins to loosen, causing the decomposed drill bit (10) to loosen in the rock layer, making it easier to pull out the decomposed drill bit (10). Step 6: The driving assembly (3) controls the device as a whole to rise via the lifting sling (7). Since the device as a whole forms a firmly bonded permanent joint with the disassembled drill bit (10), the disassembled drill bit (10) can be directly salvaged from the geothermal well (1); after being salvaged from the well, the welding cavity (9) is removed from the lifting boss (8).