Ultra-short screw drill for coiled tubing

Abstract

The invention discloses an ultra-short screw drilling tool for coiled tubing, which is applied to the technical field of screw drilling tools, and is characterized in that a drilling tool structure is arranged as a drilling device, and in a continuous drilling process, if the drilling tool structure eccentrically rotates or swings in a borehole, the drilling tool structure can rotate or swing in the borehole; the connecting hoops can be clamped at the outer concave position of the drilling tool structure on the outer side of the drilling tool structure, the centralizing bow piece between the two sets of connecting hoops on the left side surrounds the drilling tool structure, and at the moment, the centralizing wheel installed in the structural groove in the inner side of the arc-shaped plate makes contact with the well wall, so that the drilling tool is kept at the center position of a well hole; the centralizing wheel can rotate along the wheel shaft on the inner side of the wheel frame, sliding friction is converted into rolling friction, friction force is reduced, when bumping occurs due to protrusions or recesses on the inner wall of a borehole, the wheel frame and the sliding block can slide along the bottom frame so as to avoid the situation that drilling operation is affected by large bumping, and the centralizing wheel can reset quickly after normal operation.

Description

Technical Field

[0001] The invention belongs to the technical field of screw drill tools, and in particular relates to an ultra-short screw drill tool for a continuous oil pipe. Background Art

[0002] Screw drill tools are downhole power drill tools powered by drilling fluid. The drilling fluid flows into the screw drill tools from the inside of the drill string. When passing through the motor assembly, the special spiral structure of the stator and the rotor forms a pressure difference in the motor. According to the working principle of the volumetric motor, this pressure difference drives the rotor to rotate relative to the stator, thereby converting the hydraulic energy of the drilling fluid into the mechanical energy of the rotor. When operating in a wellbore with a small curvature radius, ultra-short screw drill tools are often used compared to traditional screw drill tools to meet the strict restrictions on the length of the drill tool during continuous tubing operations.

[0003] Chinese patent CN108716362B discloses a hydraulically loaded screw drill, which belongs to the technical field of oil and natural gas downhole power drill. It consists of an upper shell, a lower shell, an intermediate shell, a transmission shaft, a hollow flexure shaft and a diverter cap. A screw rotor is arranged in the upper shell, a diverter cap is arranged below the rotating screw, a transmission shaft is arranged in the lower shell on one side of the diverter cap, and a straightening bearing and a thrust bearing are arranged on the transmission shaft; a moving plate is arranged on the transmission shaft between the straightening bearing and the diverter cap, and a static plate is arranged on the inner wall of the lower shell corresponding to the moving plate. The screw drill can effectively reduce the load on the thrust bearing, and solves the problem that when the existing screw drill works underground, the thrust bearing group runs in the abrasive medium of mud, and the thrust bearing group is prone to wear and rupture failure under the action of heavy axial load, which affects the mechanical properties and service life of the screw drill.

[0004] Existing ultra-short screw drills for continuous tubing are limited in length when drilling, especially when used in wells with small curvature radius. During continuous drilling, they are prone to eccentric rotation or swing, resulting in poor stability. In addition, due to the friction resistance of the drill in the well during drilling, the energy consumption of the operation is higher in deep wells, ultra-deep wells or complex formations, and the service life of the drill may be reduced.

[0005] Based on the above-mentioned problems, we found that it is difficult for the ultra-short screw drill tools in the prior art to avoid the above problems at the same time. Even if they can be solved, they are mostly completed through stabilizers or drag reducers. Although such structures are relatively reasonable to be set on conventional screw drill tools, the installation space of ultra-short screw drill tools is limited, and the conventional auxiliary structure is integrally formed, which is difficult to be flexibly and quickly installed on the outside of the drill tool when needed. Therefore, we propose an ultra-short screw drill tool for continuous tubing that increases the friction with the well wall and can better disperse the pressure when squeezed, so that the drill tool can be kept in the center of the wellbore, improve the stability and accuracy of drilling, and prevent the drill tool from colliding with the well wall to cause damage or deviate from the predetermined trajectory. Summary of the invention

[0006] The purpose of the present invention is to target an existing ultra-short screw drill for continuous oil tubing, which has the advantages of increasing the friction with the well wall and better dispersing the pressure when squeezed, so that the drill tool can be kept in the center of the wellbore, improving the stability and accuracy of drilling, and preventing the drill tool from colliding with the well wall to cause damage or deviate from the predetermined trajectory.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions: an ultra-short screw drill for continuous tubing, comprising a drill structure, wherein three groups of connecting hoops are provided in the middle of the outer side of the drill structure, a straightening bow piece is provided between the two groups of connecting hoops on the left, an elastic sheet is bolted between the two groups of connecting hoops on the right, the elastic sheet is inclined, a ring frame is movably connected to the outer side of the elastic sheet, a hard shell is provided on the outer side of the ring frame, a contact shell is provided on the outer side of the hard shell, a rubber ring is bolted to the outer side of the contact shell, and an air bag is bolted to the inner side of the hard shell;

[0008] The straightening bow piece comprises an arc-shaped plate, five structural grooves are opened on the inner side of the arc-shaped plate, the front side and the rear side of the inner side of the structural groove are bolted to the bottom frame, the inner side of the bottom frame is slidably connected to a slider, the outer side of the slider is bolted to a wheel frame, and the inner side of the wheel frame is rotatably connected to a straightening wheel.

[0009] By adopting the above technical scheme, by setting a drill tool structure as a drilling device, during the continuous drilling process, if the drill tool structure rotates or swings eccentrically in the wellbore, the connecting hoop can be clamped in the outer concave part of the drill tool structure on the outside, and the straightening bow pieces between the two groups of connecting hoops on the left side surround the outside of the drill tool structure. At this time, the straightening wheel installed in the structural groove on the inner side of the arc plate contacts the wellbore wall, so that the drill tool is kept in the center of the wellbore. When the drill tool structure is continuously fed, the straightening wheel will rotate along the wheel axle on the inner side of the wheel frame, converting the sliding friction into rolling friction, reducing the friction force. When there are protrusions or depressions on the inner wall of the wellbore and bumps occur, the wheel frame and the slider will slide along the bottom frame to avoid large bumps affecting the drilling operation, and after normal operation It can be quickly reset, and the two groups of connecting hoops on the right are connected by elastic high-strength elastic sheets. When the external structure has large friction or radial displacement, it will produce certain deformation to avoid structural fracture. The set ring frame can also flexibly clamp the external short frame and the hard shell on the outside of the elastic sheet. The air bag on the inside of the hard shell is filled with gas during installation to ensure a firm contact between the structure and the elastic sheet. The contact shell and the rubber ring are hollowed out. The rubber ring is used to buffer vibration when it contacts the wellbore to prevent vibration from damaging the drill tool structure. When the drill tool structure is drilling in the wellbore, the friction resistance of the drill tool structure in the wellbore is reduced, especially in deep wells, ultra-deep wells or complex formations, which can reduce the operating energy consumption to a certain extent and extend the service life of the drill tool structure.

[0010] The present invention is further configured as follows: the connecting hoop comprises a top hoop, a bottom hoop and a connecting pin; the top hoop and the bottom hoop are rotatably connected via the connecting pin; and fixing bolts are provided on the front sides of the top hoop and the bottom hoop.

[0011] By adopting the above technical solution, the top hoop and the bottom hoop are connected and rotated by a connecting pin, which can facilitate the opening and closing of the structure. After the top hoop and the bottom hoop are firmly stuck on the outside of the elastic sheet, the structure is locked by fixing bolts to prevent the structure from loosening.

[0012] The present invention is further configured as follows: a protrusion is provided at the bottom of the front side of the top hoop, a recess is provided on the front side of the bottom hoop for use with the protrusion, a through hole is provided on the front sides of the top hoop and the bottom hoop, and the inner side of the through hole is movably connected to a fixing bolt.

[0013] By adopting the above technical solution, the top hoop and the bottom hoop can be matched by setting the protrusion to match the inner recess, and the set through hole is used for positioning the fixing bolts and fixing and connecting the structure.

[0014] The present invention is further configured as follows: a torsion spring is provided on the outer side of the connecting pin, and two sides of the torsion spring are bolted to the top hoop and the bottom hoop respectively.

[0015] By adopting the above technical solution, through the provision of a torsion spring, the top hoop and the bottom hoop can be further connected. At the same time, when the top hoop and the bottom hoop rotate along the connecting pin, they deform and accumulate force. When the torsion spring is reset, it will drive the top hoop and the bottom hoop to reset and close to assist the structural connection and installation.

[0016] The present invention is further configured as follows: the inner side of the bottom frame is configured as a hollow shape, a hard spring is bolted to the bottom of the inner side of the bottom frame, and the top of the hard spring is bolted to the slider.

[0017] By adopting the above technical solution, a hard spring is set to push the slider with a higher force, so that the wheel frame and the straightening wheel connected thereto are in contact with the inner wall of the wellbore. When subjected to a larger force, they deform due to the force to protect the external structure from damage due to rigid collision and extrusion.

[0018] The present invention is further configured as follows: a slide bar is provided on the inner side of the hard spring, the top and the bottom of the slide bar are both bolted to the bottom frame, and the outer side of the slide bar is slidably connected to the slider.

[0019] By adopting the above technical solution and setting a slide rod, the movement of the slider can be limited to avoid the structure from rotating or tilting and causing it to be unable to be used normally.

[0020] The present invention is further configured as follows: a connecting spring is bolted to the outer side of the hard shell, and the outer side of the connecting spring is bolted to the contact shell.

[0021] By adopting the above technical solution, by setting a connecting spring, the hard shell and the contact shell can be easily connected, and a certain displacement space is provided for them. When the external structure is subjected to excessive force, the connecting spring is deformed, causing the contact shell to displace along the hard shell to buffer the force protection structure.

[0022] The present invention is further configured as follows: a short frame is bolted to the outer side of the ring frame, and the outer side of the short frame is bolted to the hard shell.

[0023] By adopting the above technical solution and providing a short frame, the ring frame and the hard shell can be easily connected, and a certain distance can be left between them to provide installation space for the airbag.

[0024] The present invention is further configured as follows: a through hole is opened on the inner side of the ring frame, a pin rod is inserted into the inner side of the through hole, and a fixing screw sleeve is threadedly connected to the outer side of the pin rod.

[0025] By adopting the above technical solution, through-holes are provided to cooperate with the pin rods, so that the two sets of ring frames can be easily connected. After the pin rods are inserted into the through-holes, the fixing screw sleeves can be screwed onto the outside of the pin rods to complete the fixation of the structure.

[0026] The present invention is further configured as follows: the straightening wheel is made of a hard alloy material, a friction pattern is provided on the surface of the straightening wheel, and the elastic sheet is made of a high-strength alloy steel material and is slightly raised toward the outside.

[0027] By adopting the above technical solution, the straightening wheel made of cemented carbide has sufficient strength, the friction texture increases the friction with the well wall, and can better disperse the pressure when squeezed. The elastic sheet made of high-strength alloy steel material has good elasticity and corrosion resistance.

[0028] In summary, the present invention has the following beneficial effects:

[0029] By setting the drill tool structure as the drilling device, during the continuous drilling process, if the drill tool structure rotates or swings eccentrically in the wellbore, the connecting hoop can be clamped in the outer concave part of the drill tool structure on the outside, and the straightening bow pieces between the two groups of connecting hoops on the left side surround the outside of the drill tool structure. At this time, the straightening wheel installed in the structural groove on the inner side of the arc plate contacts the wellbore wall to keep the drill tool in the center of the wellbore. When the drill tool structure is continuously fed, the straightening wheel will rotate along the wheel axle on the inner side of the wheel frame, converting the sliding friction into rolling friction and reducing the friction. When there are protrusions or depressions on the inner wall of the wellbore and bumps occur, the wheel frame and the slider will slide along the bottom frame to avoid large bumps affecting the drilling operation, and quickly reset after normal operation. The two groups of connecting hoops on the right are connected by elastic high-strength elastic sheets. When the external structure has large friction or radial displacement, it will produce certain deformation to avoid structural fracture. The set ring frame can also flexibly clamp the external short frame and the hard shell on the outside of the elastic sheet. The air bag inside the hard shell is filled with gas during installation to ensure a stable contact between the structure and the elastic sheet. The contact shell and the rubber ring are hollowed out. The rubber ring is used to buffer vibration when it contacts the wellbore to prevent vibration from damaging the drill tool structure. When the drill tool structure is drilling in the wellbore, the friction resistance of the drill tool structure in the wellbore is reduced, especially in deep wells, ultra-deep wells or complex formations, which can reduce the operating energy consumption to a certain extent and extend the service life of the drill tool structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 It is a schematic diagram of the structure of the straightening limb of the present invention;

[0032] Figure 3 It is a schematic diagram of the structure of the connecting hoop of the present invention;

[0033] Figure 4 is a schematic diagram of the connection of the hard shell of the present invention;

[0034] Figure 5 is a schematic diagram of the hard shell structure of the present invention;

[0035] Figure 6 is a schematic diagram of the position of the airbag of the present invention;

[0036] Figure 7 It is a left view of the hard shell structure of the present invention;

[0037] Figure 8 It is a schematic diagram of the structure of the straightening limb of the present invention;

[0038] Fig. 9 It is a schematic diagram of the wheel frame structure of the present invention.

[0039] Figure numerals: 1. drilling tool structure; 2. connecting hoop; 201. top hoop; 202. bottom hoop; 203. connecting pin; 204. fixing bolt; 3. straightening bow piece; 301. arc plate; 302. bottom frame; 303. slider; 304. structural groove; 305. straightening wheel; 306. wheel frame; 4. elastic sheet; 5. ring frame; 6. short frame; 7. hard shell; 8. contact shell; 9. rubber ring; 10. air bag; 11. through hole; 12. torsion spring; 13. hard spring; 14. slide rod; 15. connecting spring; 16. through hole; 17. pin rod; 18. fixing screw sleeve. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0041] Embodiment 1:

[0042] refer to Figure 1-9 An ultra-short screw drill for a coiled tubing includes a drill structure 1, three groups of connecting hoops 2 are arranged in the middle of the outer side of the drill structure 1, a straightening bow piece 3 is arranged between the two groups of connecting hoops 2 on the left side, an elastic sheet 4 is bolted between the two groups of connecting hoops 2 on the right side, the elastic sheet 4 is inclined, a ring frame 5 is movably connected to the outer side of the elastic sheet 4, a hard shell 7 is arranged on the outer side of the ring frame 5, a contact shell 8 is arranged on the outer side of the hard shell 7, a rubber ring 9 is bolted to the outer side of the contact shell 8, and an air bag 10 is bolted to the inner side of the hard shell 7;

[0043] The righting bow 3 comprises an arc plate 301, and five structural grooves 304 are formed on the inner side of the arc plate 301. The front and rear sides of the inner side of the structural grooves 304 are both bolted to the bottom frame 302. The inner side of the bottom frame 302 is slidably connected to a slider 303. The outer side of the slider 303 is bolted to a wheel frame 306. The inner side of the wheel frame 306 is rotatably connected to a righting wheel 305.

[0044] By setting the drill tool structure 1 as a drilling device, during the continuous drilling process, if the drill tool structure 1 rotates or swings eccentrically in the wellbore, the connecting hoop 2 can be clamped in the outer concave part of the drill tool structure 1 on the outside of the drill tool structure 1, and the straightening bow piece 3 between the two groups of connecting hoops 2 on the left side surrounds the outside of the drill tool structure 1. At this time, the straightening wheel 305 installed in the structural groove 304 on the inner side of the arc plate 301 contacts the wellbore wall to keep the drill tool in the center of the wellbore. When the drill tool structure 1 is continuously fed, the straightening wheel 305 will rotate along the wheel axle on the inner side of the wheel frame 306, converting the sliding friction into rolling friction and reducing the friction. When there are protrusions or depressions on the inner wall of the wellbore and bumps occur, the wheel frame 306 and the slider 303 will slide along the bottom frame 302 to avoid large bumps affecting the drilling operation, and quickly reset after normal operation.

[0045] like Figure 3 As shown, the connecting hoop 2 includes a top hoop 201, a bottom hoop 202 and a connecting pin 203. The top hoop 201 and the bottom hoop 202 are rotatably connected by the connecting pin 203. The front sides of the top hoop 201 and the bottom hoop 202 are provided with fixing bolts 204. By arranging that the top hoop 201 and the bottom hoop 202 are connected and rotated by the connecting pin 203, the opening and closing of the structure can be facilitated, and after the top hoop 201 and the bottom hoop 202 are firmly clamped on the outer side of the elastic sheet 4, the fixing bolts 204 are used to complete the locking of the structure to prevent the structure from loosening.

[0046] like Figure 3 As shown, a protrusion is provided at the bottom of the front side of the top hoop 201, and a recess is provided on the front side of the bottom hoop 202 for use with the protrusion. A through hole 11 is provided on the front sides of the top hoop 201 and the bottom hoop 202, and the inner side of the through hole 11 is movably connected with the fixing bolt 204. By setting the protrusion and the recess, the top hoop 201 and the bottom hoop 202 can be matched. The through hole 11 is used for positioning the fixing bolt 204 and fixing and connecting the structure.

[0047] like Figure 3 As shown, a torsion spring 12 is provided on the outer side of the connecting pin 203, and the two sides of the torsion spring 12 are bolted to the top hoop 201 and the bottom hoop 202 respectively. By providing the torsion spring 12, the top hoop 201 and the bottom hoop 202 can be further connected. At the same time, when the top hoop 201 and the bottom hoop 202 rotate along the connecting pin 203, they deform and accumulate force. When the torsion spring 12 is reset, it will drive the top hoop 201 and the bottom hoop 202 to reset and close to assist the structural connection and installation.

[0048] like Fig. 9As shown, the inner side of the bottom frame 302 is hollowed out, and a hard spring 13 is bolted to the bottom of the inner side of the bottom frame 302. The top of the hard spring 13 is bolted to the slider 303. The hard spring 13 is provided to push the slider 303 with a higher force, so that the wheel frame 306 and the straightening wheel 305 connected thereto are in contact with the inner wall of the wellbore. When subjected to a larger force, they are deformed due to the force to protect the external structure from being damaged due to rigid collision and extrusion.

[0049] like Fig. 9 As shown, a slide bar 14 is provided on the inner side of the hard spring 13, the top and bottom of the slide bar 14 are bolted to the bottom frame 302, and the outer side of the slide bar 14 is slidably connected to the slider 303. By setting the slide bar 14, the movement of the slider 303 can be limited to avoid the structure from rotating or tilting and causing it to be unable to be used normally.

[0050] Brief description of the use process: During use, if the drilling tool structure 1 rotates or swings eccentrically in the wellbore, the connecting hoop 2 can be clamped in the outer concave part of the drilling tool structure 1 on the outer side of the drilling tool structure 1, and the straightening bow piece 3 between the two groups of connecting hoops 2 on the left side surrounds the outside of the drilling tool structure 1, and the straightening wheel 305 in the structural groove 304 on the inner side of the arc plate 301 contacts the wellbore wall to keep the drilling tool in the center of the wellbore. When the drilling tool structure 1 is continuously fed, the straightening wheel 305 will rotate along the wheel axle on the inner side of the wheel frame 306, converting the sliding friction into rolling friction and reducing the friction. When there are protrusions or depressions on the inner wall of the wellbore and bumps occur, the wheel frame 306 and the slider 303 will slide along the bottom frame 302, and the hard spring 13 will be compressed and deformed at this time, and the hard spring 13 will be reset when the environment in the wellbore is normal to facilitate subsequent operations.

[0051] Embodiment 2:

[0052] refer to Figure 1-7 An ultra-short screw drill for a coiled tubing includes a drill structure 1, three groups of connecting hoops 2 are arranged in the middle of the outer side of the drill structure 1, a straightening bow piece 3 is arranged between the two groups of connecting hoops 2 on the left side, an elastic sheet 4 is bolted between the two groups of connecting hoops 2 on the right side, the elastic sheet 4 is inclined, a ring frame 5 is movably connected to the outer side of the elastic sheet 4, a hard shell 7 is arranged on the outer side of the ring frame 5, a contact shell 8 is arranged on the outer side of the hard shell 7, a rubber ring 9 is bolted to the outer side of the contact shell 8, and an air bag 10 is bolted to the inner side of the hard shell 7;

[0053] The two groups of connecting hoops 2 on the right are connected by elastic high-strength elastic sheets 4. When the external structure is subject to large friction or radial displacement, certain deformation will occur to avoid structural fracture. The set ring frame 5 can also flexibly clamp the external short frame 6 and the hard shell 7 on the outside of the elastic sheet 4. The air bag 10 on the inside of the hard shell 7 is filled with gas during installation to ensure a stable contact between the structure and the elastic sheet 4. The contact shell 8 and the rubber ring 9 are hollowed out. The rubber ring 9 is used to buffer vibration when in contact with the wellbore to prevent vibration from causing damage to the drilling tool structure 1. When the drilling tool structure 1 is drilling in the wellbore, the friction resistance of the drilling tool structure 1 in the wellbore is reduced, especially in deep wells, ultra-deep wells or complex formations, which can reduce the operating energy consumption to a certain extent and extend the service life of the drilling tool structure 1.

[0054] like Figure 7 As shown, the outer side of the hard shell 7 is bolted with a connecting spring 15, and the outer side of the connecting spring 15 is bolted to the contact shell 8. By setting the connecting spring 15, the hard shell 7 and the contact shell 8 can be easily connected, and a certain displacement space is provided for them relative to each other. When the external structure is subjected to excessive force, the connecting spring 15 is deformed, causing the contact shell 8 to be displaced along the hard shell 7 to buffer the force protection structure.

[0055] like Figure 6 As shown, a short frame 6 is bolted to the outer side of the ring frame 5, and the outer side of the short frame 6 is bolted to the hard shell 7. By providing the short frame 6, the ring frame 5 and the hard shell 7 can be easily connected, and a certain distance can be left between them to provide installation space for the airbag 10.

[0056] like Figure 6 and Figure 5 As shown, a through hole 16 is opened on the inner side of the ring frame 5, a pin rod 17 is inserted into the inner side of the through hole 16, and a fixing screw sleeve 18 is threadedly connected to the outer side of the pin rod 17. By providing the through hole 16 and matching the pin rod 17, it is convenient to connect the two groups of ring frames 5. After the pin rod 17 is inserted into the through hole 16, the fixing screw sleeve 18 can be screwed onto the outer side of the pin rod 17 to complete the fixation of the structure.

[0057] like Figure 2 As shown, the straightening wheel 305 is made of a hard alloy material, and a friction pattern is provided on the surface of the straightening wheel 305. The elastic sheet 4 is made of a high-strength alloy steel material and is slightly raised toward the outside. The straightening wheel 305 made of a hard alloy material has sufficient strength, and the friction pattern increases the friction with the well wall, and can better disperse the pressure when squeezed. The elastic sheet 4 made of a high-strength alloy steel material has good elasticity and corrosion resistance.

[0058] Brief description of the use process: When it is necessary to improve the drilling stability, the two sets of ring frames 5 are clamped on the outside of the elastic sheet 4, and the pin rod 17 is inserted into the through hole 16. After the fixing screw sleeve 18 is screwed on the outside of the pin rod 17, the connection of the structure is completed. When the external structure has large friction or radial displacement, it will produce a certain deformation to avoid structural fracture. The set ring frame 5 can also flexibly clamp the external short frame 6 and the hard shell 7 on the outside of the elastic sheet 4. The air bag 10 on the inside of the hard shell 7 is filled with gas during installation to ensure that the structure is in stable contact with the elastic sheet 4, and the contact shell 8 and the rubber ring 9 are hollowed out. The rubber ring 9 is used to buffer vibration when it contacts the wellbore to prevent vibration from damaging the drilling tool structure 1. The air bag 10 itself, which is used as an installation and fixing structure, can also play a certain shock-absorbing and buffering role.

[0059] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. An ultra-short screw drill for coiled tubing, comprising a drill structure (1), characterized in that: Three groups of connecting hoops (2) are provided in the middle of the outer side of the drilling tool structure (1), a straightening bow piece (3) is provided between the two groups of connecting hoops (2) on the left side, an elastic sheet (4) is bolted between the two groups of connecting hoops (2) on the right side, the elastic sheet (4) is arranged obliquely, a ring frame (5) is movably connected to the outer side of the elastic sheet (4), a hard shell (7) is provided on the outer side of the ring frame (5), a contact shell (8) is provided on the outer side of the hard shell (7), a rubber ring (9) is bolted to the outer side of the contact shell (8), and an air bag (10) is bolted to the inner side of the hard shell (7); The straightening bow piece (3) comprises an arc-shaped plate (301), the inner side of the arc-shaped plate (301) is provided with five structural grooves (304), the front side and the rear side of the inner side of the structural groove (304) are both bolted to a bottom frame (302), the inner side of the bottom frame (302) is slidably connected to a slider (303), the outer side of the slider (303) is bolted to a wheel frame (306), and the inner side of the wheel frame (306) is rotatably connected to a straightening wheel (305).

2. The ultra-short screw drill for coiled tubing according to claim 1, characterized in that: The connecting hoop (2) comprises a top hoop (201), a bottom hoop (202) and a connecting pin (203); the top hoop (201) and the bottom hoop (202) are rotatably connected via the connecting pin (203); and fixing bolts (204) are provided on the front sides of the top hoop (201) and the bottom hoop (202).

3. The ultra-short screw drill for coiled tubing according to claim 2, characterized in that: A protrusion is provided at the bottom of the front side of the top hoop (201), and a recess is provided on the front side of the bottom hoop (202) for use with the protrusion. A through hole (11) is provided on the front sides of both the top hoop (201) and the bottom hoop (202), and the inner side of the through hole (11) is movably connected to a fixing bolt (204).

4. The ultra-short screw drill for coiled tubing according to claim 2, characterized in that: A torsion spring (12) is provided on the outer side of the connecting pin (203), and two sides of the torsion spring (12) are bolted to the top hoop (201) and the bottom hoop (202) respectively.

5. The ultra-short screw drill for coiled tubing according to claim 1, characterized in that: The inner side of the bottom frame (302) is designed to be hollow, and a hard spring (13) is bolted to the bottom of the inner side of the bottom frame (302), and the top of the hard spring (13) is bolted to the slider (303).

6. The ultra-short screw drill for coiled tubing according to claim 5, characterized in that: A sliding rod (14) is provided on the inner side of the hard spring (13); the top and bottom of the sliding rod (14) are bolted to the bottom frame (302); and the outer side of the sliding rod (14) is slidably connected to the slider (303).

7. The ultra-short screw drill for coiled tubing according to claim 1, characterized in that: A connecting spring (15) is bolted to the outer side of the hard shell (7), and the outer side of the connecting spring (15) is bolted to the contact shell (8).

8. The ultra-short screw drill for coiled tubing according to claim 1, characterized in that: A short frame (6) is bolted to the outer side of the ring frame (5), and the outer side of the short frame (6) is bolted to a hard shell (7).

9. The ultra-short screw drill for coiled tubing according to claim 1, characterized in that: A through hole (16) is provided on the inner side of the ring frame (5), a pin rod (17) is inserted into the inner side of the through hole (16), and a fixing screw sleeve (18) is threadedly connected to the outer side of the pin rod (17).

10. The ultra-short screw drill for coiled tubing according to claim 1, characterized in that: The straightening wheel (305) is made of a hard alloy material. The surface of the elastic sheet (4) is provided with friction lines, and the elastic sheet (4) is made of high-strength alloy steel material. And it is slightly raised toward the outside.

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