CN112096293B

CN112096293B - Variable-diameter drill bit for oil field drilling

Info

Publication number: CN112096293B
Application number: CN202011282947.8A
Authority: CN
Inventors: 郭庆明; 周玉华; 董惠芹; 杨守亮; 孙志鹏; 于洪锋
Original assignee: Drilling Tool Factory Of Gubang Petroleum Equipment Co ltd Shengli Oilfield; Shengli Oil Field Solid State Petroleum Equipment Co ltd
Current assignee: Drilling Tool Factory Of Gubang Petroleum Equipment Co ltd Shengli Oilfield; Shengli Oil Field Solid State Petroleum Equipment Co ltd
Priority date: 2020-11-17
Filing date: 2020-11-17
Publication date: 2021-02-09
Anticipated expiration: 2040-11-17
Also published as: CN112096293A

Abstract

The invention discloses a variable-diameter drill bit for oil field drilling, which comprises a connecting rod, a fixing ring, a drill rod, a first drill bit, a second drill bit and an adjusting mechanism, wherein the connecting rod and the drill rod are fixedly installed together through the fixing ring; after adopting above-mentioned structure for this variable diameter drill bit for oil field well drilling can be at the well drilling in-process, in time change the diameter of first drill bit, avoids the card to hinder, carries out the drilling operation smoothly, and first drill bit and second drill bit installation, dismantlement are simple convenient, avoid first drill bit and second drill bit to damage the back and follow the trade on a large scale, and the extravagant resource has made things convenient for the maintenance of first drill bit and second drill bit simultaneously.

Description

Variable-diameter drill bit for oil field drilling

Technical Field

The invention relates to the technical field of oil field drilling, in particular to a variable-diameter drill bit for oil field drilling.

Background

The petroleum drilling engineering is a system engineering which utilizes petroleum drilling equipment to drill a plurality of sets of stratums from the ground along a designed track to reach a preset target stratum (a hydrocarbon reservoir or a possible hydrocarbon reservoir) to form a stable channel (a hydrocarbon well) for producing or injecting required fluids (water, gas and steam), completes coring, logging and testing work during the drilling process and after the drilling is finished, and obtains various information required by exploration, development and drilling. In order to safely and quickly complete the drilling task of a well, well drilling design must be carefully made before construction. The well design usually includes two parts of well geological design and well engineering design, and the well engineering design includes process technology design, construction period design, well cost budget and the like.

The diameter of a drill bit used for oil field drilling in the prior art is usually a fixed diameter, and the following defects and shortcomings exist in practical drilling application: 1) in the drilling process, due to friction loss between the drill bit and the stratum, the diameter of the drill bit can be continuously reduced, so that a borehole drilled by the drill bit is gradually reduced, and after the drill bit is pulled down midway and replaced, a new drill bit is difficult to drill because the diameter of the new drill bit is the standard diameter and the diameter of a deep well is smaller than the standard diameter of the drill bit; 2) when the drill bit drills in the stratum with the diameter easy to be reduced, the drill bit can not be smoothly taken out from the well diameter due to the fact that water absorption reducing or plastic reducing occurs in the drilling process, and blocking often occurs.

The patent with the patent publication number of CN206830055U discloses a variable-diameter drill bit for oil field drilling, which comprises a drill rod, wherein the bottom surface of the drill rod is provided with a convex column protruding downwards, an air passage used for connecting an external pneumatic pump is arranged in the drill rod, and the air passage extends to the peripheral surface of the convex column; adjust the drill bit, adjust the drill bit and have roof, diapire and lateral wall, the lateral wall is connected in same one side of roof and diapire, and the surface of lateral wall, diapire is equipped with a plurality of brill teeth respectively, and roof and diapire can be followed the joint of the radial movement of projection on the projection, and the outer peripheral face of roof, lateral wall, diapire and projection encloses to close and forms the reducing regulation chamber that is linked together with the air flue. Although the diameter of the variable-diameter drill bit can be changed, the drilling operation can be carried out more smoothly and conveniently, and the drilling operation can be carried out smoothly by avoiding blockage when drilling in a formation with easy diameter reduction; however, the following problems still remain: 1) the drill bit is inconvenient to install and disassemble, so that the time cost is improved; 2) the diameter of the drill bit is changed through air pressure, so that the drill bit is not stable enough, and meanwhile, external equipment needs to be connected, and the equipment cost is increased; 3) and the clamp is connected, so that the stability is not high enough and the falling is easy.

Disclosure of Invention

In order to overcome the technical problems, the invention aims to provide a variable-diameter drill bit for oil field drilling, which can ensure that a rotating shaft is more stable in the rotating process while reducing the diameter, and avoids the generation of deviation and the motion blockage; external slurry is prevented from entering the device; the displacement of parts caused by installation deviation is avoided; the service life of the first drill bit is prolonged, the contact surface of the second drill bit with rock debris and soil is increased, and the drilling speed is accelerated.

The purpose of the invention can be realized by the following technical scheme:

the variable-diameter drill bit for oilfield drilling comprises a connecting rod, a fixing ring, a drill rod, first drill bits, second drill bits and an adjusting mechanism, wherein the connecting rod and the drill rod are fixedly installed together through the fixing ring;

guiding mechanism includes first servo motor, axis of rotation, mobile station, linking bridge, ejector pad, the spacing ka tai of second, first servo motor's output shaft fixedly connected with axis of rotation, the axis of rotation upper end is provided with the rotation round platform, the axis of rotation bottom is provided with first spacing ka tai, the axis of rotation bottom just is located first spacing ka tai below and has seted up the fifth external screw thread, the axis of rotation bottom just is located fifth external screw thread below and installs the spacing ka tai of second through the pin one, the outside threaded connection of fifth external screw thread has the mobile station, the mobile station rotates through pin two and is connected with four linking bridge, four angular distribution such as linking bridge, the linking bridge other end rotates through pin two and connects on the ejector pad.

As a further scheme of the invention: the top of the connecting rod is provided with a first connecting platform, the outer side surface of the first connecting platform is provided with a first external thread, the top of the first connecting platform is provided with a first mounting groove, the first servo motor is fixedly arranged in the first mounting groove, the outer side of the middle part of the connecting rod is provided with a first boss, the bottom side of the middle part of the connecting rod is provided with a first sealing groove, a first sealing gasket is arranged in the first sealing groove, the bottom of the connecting rod is provided with a second connecting platform, the bottom of the second connecting platform is provided with four guide posts which are distributed at equal angles, the connecting rod is internally provided with a second mounting groove, the top of the second mounting groove is provided with a first fixing groove, a through hole is arranged between the first fixing groove and the first mounting groove, the top end of the rotating shaft is rotatably arranged in the first fixing groove, and the output shaft, the rotary round table is rotatably installed in the second installation groove.

As a further scheme of the invention: first connecting groove has been seted up to solid fixed ring bottom, first internal thread has been seted up on the first connecting groove cell wall, gu fixed ring cup joints on the connecting rod, first connecting groove top surface contacts with first boss top surface, gu fixed ring lateral surface is provided with four rotary platform, four rotary platform is about solid fixed ring central symmetry distributes.

As a further scheme of the invention: the outer side of the top end of the drill rod is provided with a second external thread, the top of the drill rod is provided with a second boss, the second boss is clamped in the first sealing groove, the second external thread is in threaded connection with a first internal thread of the fixing ring, the center of the top of the drill rod is provided with a third mounting groove, a second sealing gasket is placed at the bottom of the third mounting groove, the third mounting groove is matched and mounted with the second connecting table of the connecting rod, the bottom of the third mounting groove is provided with four guide grooves which are equiangularly distributed and correspond to the positions of the guide posts one by one, a first oblique angle is poured at the top of the guide groove, the guide posts are inserted in the guide grooves, a second connecting groove is formed at the bottom of the drill rod, a second internal thread is formed on the inner connecting groove wall of the second connecting groove, a fifth mounting groove is formed in the bottom surface of the middle, eight second draw-in grooves have been seted up on the drilling rod bottom axial plane, the fourth mounting groove has been seted up between second spread groove and the third mounting groove, four first mounting holes have been seted up on the fourth mounting groove cell wall, four angular distribution such as first mounting hole, ejector pad slidable mounting is in first mounting hole, be provided with the fourth on the first mounting hole pore wall and seal up the pad, first spacing ka tai rotates and installs in the fourth mounting groove.

As a further scheme of the invention: the sixth mounting groove has been seted up at the second drill bit top, the third draw-in groove has been seted up to the inside one side of sixth mounting groove, second drill bit top center is provided with the third and connects the platform, the third external screw thread has been seted up to the third connection platform lateral surface, the second drill bit passes through third external screw thread threaded connection on the second internal thread of drilling rod, be provided with the third sealed pad between third connection platform top surface and the second spread groove tank bottom, the seventh mounting groove has been seted up at third connection platform center, the second fixed slot has been seted up to seventh mounting groove tank bottom, the axis of rotation bottom is rotated and is installed in the second fixed slot, the second drill bit is the toper, and has seted up the fourth external screw thread on the axial plane, second drill bit bottom center is provided with the second and bores tooth.

As a further scheme of the invention: first drill bit lateral surface is provided with the first brill tooth of a plurality of, a plurality of first brill tooth is the matrix distribution, both ends all are provided with first ka tai about the first drill bit inboard, first ka tai top one side is provided with the third boss, first drill bit medial surface symmetry is provided with the fourth boss, fourth boss and second draw-in groove adaptation, third boss and first draw-in groove and third draw-in groove adaptation, first draw-in groove and third draw-in groove structure are identical completely, first drill bit medial surface middle part and ejector pad fixed connection, first drill bit lateral surface bottom has the second oblique angle to fall.

As a further scheme of the invention: the lower extreme axial plane of fifth mounting groove, first draw-in groove, second draw-in groove, sixth mounting groove, third draw-in groove and drilling rod all is provided with sliding seal pad, rotate round platform and second mounting groove adaptation, first spacing ka tai external diameter equals with the rotation round platform external diameter.

The invention has the beneficial effects that:

1. through set up rotation round platform and first spacing ka tai in the axis of rotation to make rotation round platform and second mounting groove adaptation, first spacing ka tai external diameter equals with rotation round platform external diameter, makes the axis of rotation more stable at the rotation in-process, has avoided producing the skew, causes the motion card to die.

2. Through setting up first spacing ka tai and the spacing ka tai of second, avoid the mobile station at the in-process that reciprocates, remove excessively, cause the part to damage.

3. Through setting up first sealed pad, second sealed pad, sliding seal pad, third sealed pad, fourth sealed pad, realize the sealed processing of whole device, avoid outside mud to get into the device in, cause the device to damage.

4. Through setting up guide way and guide post, the part installation of being convenient for avoids the installation skew to produce the part and shifts.

5. Through falling the second oblique angle in first drill bit lateral surface bottom, avoid first drill bit stress to concentrate on the bottom most advanced, improve first drill bit life, the second drill bit is the toper simultaneously, and sets up the fourth external screw thread on the axial plane, increases the contact surface of second drill bit and detritus, earth for drilling speed alleviates the pressure that the second drill bit head bore simultaneously.

6. The detachable connecting rod, the drill rod, the first drill bit and the second drill bit are arranged, so that the whole device is convenient to detach and install, meanwhile, time and resources are saved for maintenance and repair, the cost of replacing parts is reduced, and the cost is saved.

Drawings

The invention will be further described with reference to the accompanying drawings.

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic view of the overall cross-sectional structure of the present invention;

FIG. 3 is a schematic cross-sectional view of a connecting rod according to the present invention;

FIG. 4 is a schematic perspective view of a connecting rod according to the present invention;

FIG. 5 is a schematic view of a retaining ring according to the present invention;

FIG. 6 is an enlarged view of the area A in FIG. 2;

FIG. 7 is a cross-sectional view of the drill rod of the present invention;

FIG. 8 is a perspective view of the drill stem of the present invention;

FIG. 9 is a schematic view of the inner structure of the third mounting groove of the present invention;

FIG. 10 is a schematic view of a second bit of the present invention;

FIG. 11 is a schematic view of the adjusting mechanism of the present invention;

fig. 12 is an enlarged structure diagram of a region B in fig. 2.

In the figure: 1. a connecting rod; 2. a fixing ring; 3. a drill stem; 4. a first drill bit; 5. a second drill bit; 6. an adjustment mechanism; 7. a first gasket; 8. a second gasket; 9. a sliding seal gasket; 10. a third gasket; 11. a first connection station; 111. a first external thread; 112. a first mounting groove; 113. a through hole; 114. a first fixing groove; 12. a second mounting groove; 13. a first boss; 14. a first seal groove; 15. a second connecting station; 16. a guide post; 21. a first connecting groove; 211. a first internal thread; 22. rotating the platform; 31. a second boss; 32. a second external thread; 33. a third mounting groove; 34. a fourth mounting groove; 35. a fifth mounting groove; 351. a first card slot; 36. a second card slot; 37. a second connecting groove; 371. a second internal thread; 38. a guide groove; 39. a first bevel; 40. a first mounting hole; 41. a first drill tooth; 42. a first chuck table; 43. a third boss; 44. a fourth boss; 45. a second bevel; 51. a sixth mounting groove; 511. a third card slot; 52. a third connecting station; 521. a third external thread; 53. a fourth external thread; 54. a seventh mounting groove; 55. a second fixing groove; 56. a second drill tooth; 61. a first servo motor; 62. a rotating shaft; 621. rotating the circular truncated cone; 622. a first limit clamping table; 623. a fifth external thread; 63. a mobile station; 64. connecting a bracket; 65. a push block; 66. a second limit clamping table; 100. and a fourth gasket.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 12, the variable diameter drill bit for oilfield drilling comprises a connecting rod 1, a fixing ring 2, a drill rod 3, a first drill bit 4, a second drill bit 5 and an adjusting mechanism 6, wherein the connecting rod 1 and the drill rod 3 are fixedly installed together through the fixing ring 2, the bottom of the drill rod 3 is in threaded connection with the second drill bit 5, four first drill bits 4 are installed between the second drill bit 5 and the drill rod 3 in a matched manner, the four first drill bits 4 are distributed at equal angles, and the adjusting mechanism 6 is installed inside the connecting rod 1, the drill rod 3 and the second drill bit 5 in a matched manner;

the adjusting mechanism 6 comprises a first servo motor 61, a rotating shaft 62, a moving table 63, a connecting bracket 64, a pushing block 65 and a second limiting clamping table 66, wherein the rotating shaft 62 is fixedly connected to an output shaft of the first servo motor 61, a rotating round table 621 is arranged at the upper end of the rotating shaft 62, the rotating stability of the rotating shaft 62 is maintained, the deviation is avoided, the first limiting clamping table 622 is arranged at the bottom end of the rotating shaft 62, the moving table 63 is prevented from moving upwards excessively and damaging parts, a fifth external thread 623 is arranged at the bottom end of the rotating shaft 62 and below the first limiting clamping table 622, a second limiting clamping table 66 is arranged at the bottom end of the rotating shaft 62 and below the fifth external thread 623 through a first pin, the moving table 63 is prevented from moving downwards and damaging parts, the moving table 63 is in external threaded connection with the fifth external thread 623, and the moving table 63 is connected with four connecting brackets 64 through a second pin, the four connecting brackets 64 are distributed at equal angles, and the other ends of the connecting brackets 64 are rotatably connected to the pushing block 65 through second pins.

The top of the connecting rod 1 is provided with a first connecting platform 11, the outer side surface of the first connecting platform 11 is provided with a first external thread 111, the top of the first connecting platform 11 is provided with a first mounting groove 112, the first servo motor 61 is fixedly mounted in the first mounting groove 112, the outer side of the middle part of the connecting rod 1 is provided with a first boss 13, the bottom side of the middle part of the connecting rod 1 is provided with a first sealing groove 14, a first sealing gasket 7 is arranged in the first sealing groove 14 to prevent external mud at the joint of the connecting rod 1 and a drill rod 3 from entering into a drill bit to damage parts in the drilling operation process, the bottom of the connecting rod 1 is provided with a second connecting platform 15, the bottom of the second connecting platform 15 is provided with four guide posts 16, and the four guide posts 16 are arranged and positioned to avoid installation deviation, so that the rotating shaft 62 is inclined to cause the blocking of, second mounting groove 12 has been seted up to connecting rod 1 is inside, first fixed slot 114 has been seted up at second mounting groove 12 top, through-hole 113 has been seted up between first fixed slot 114 and the first mounting groove 112, the rotation axis 62 top is rotated and is installed in first fixed slot 114, the output shaft of first servo motor 61 passes through-hole 113 and is connected with the rotation axis 62 top, rotate round platform 621 and rotate and install in second mounting groove 12, support rotation axis 62 and rotate, and remain stable, avoid the skew.

The bottom end of the fixing ring 2 is provided with a first connecting groove 21, the wall of the first connecting groove 21 is provided with a first internal thread 211, the fixing ring 2 is sleeved on the connecting rod 1, the top surface of the first connecting groove 21 is contacted with the top surface of the first boss 13, the outer side surface of the fixing ring 2 is provided with four rotating platforms 22, and the four rotating platforms 22 are distributed in a central symmetry mode about the fixing ring 2; the fixing ring 2 is convenient to rotate to lock the connecting rod 1 and the drill rod 3.

The outer side of the top end of the drill rod 3 is provided with a second external thread 32, the top of the drill rod 3 is provided with a second boss 31, the second boss 31 is clamped in the first sealing groove 14 and is sealed upwards to more effectively prevent external slurry from entering the device, the second external thread 32 is in threaded connection with the first internal thread 211 of the fixing ring 2, the center of the top of the drill rod 3 is provided with a third mounting groove 33, a second sealing gasket 8 is placed at the bottom of the third mounting groove 33 to form double-layer sealing with the first sealing gasket 7 to improve the sealing effect, the third mounting groove 33 is in adaptive installation with the second connecting table 15 of the connecting rod 1, the bottom of the third mounting groove 33 is provided with four guide grooves 38, the four guide grooves 38 are distributed at equal angles and are in one-to-one correspondence with the positions of the guide columns 16, the top of the guide grooves 38 is inverted with a first oblique angle 39, meanwhile, the guide column 16 is inserted into the guide groove 38, the bottom of the drill rod 3 is provided with a second connecting groove 37, the inner groove wall of the second connecting groove 37 is provided with a second internal thread 371, the bottom surface of the middle part of the drill rod 3 is provided with a fifth mounting groove 35, one side of the bottom of the fifth mounting groove 35 is provided with a first clamping groove 351, the shaft surface of the bottom end of the drill rod 3 is provided with eight second clamping grooves 36, a fourth mounting groove 34 is arranged between the second connecting groove 37 and the third mounting groove 33, the groove wall of the fourth mounting groove 34 is provided with four first mounting holes 40, the four first mounting holes 40 are distributed at equal angles, the push block 65 is slidably mounted in the first mounting hole 40, the hole wall of the first mounting hole 40 is provided with a fourth sealing gasket 100, so that the first drill bit 4 is prevented from driving external slurry to enter the device, the first limit stop 622 is rotatably mounted in the fourth mounting slot 34.

The top of the second drill bit 5 is provided with a sixth mounting groove 51, one side inside the sixth mounting groove 51 is provided with a third clamping groove 511, the center of the top of the second drill bit 5 is provided with a third connecting table 52, the outer side surface of the third connecting table 52 is provided with a third external thread 521, the second drill bit 5 is in threaded connection with a second internal thread 371 of the drill rod 3 through the third external thread 521, the second drill bit 5 and the first drill bit 4 are convenient to replace in the later period, damage is reduced, and replaced parts are saved, resources are saved, a third sealing gasket 10 and a sealing device are arranged between the top surface of the third connecting table 52 and the bottom of the second connecting groove 37 to prevent foreign matters from entering, the center of the third connecting table 52 is provided with a seventh mounting groove 54, the bottom of the seventh mounting groove 54 is provided with a second fixing groove 55, the bottom of the rotating shaft 62 is rotatably mounted in the second fixing groove 55, and, and the shaft surface is provided with a fourth external thread 53, so that the contact surface of the second drill bit 5 with rock debris and soil is increased, the drilling speed is accelerated, the pressure borne by the head of the second drill bit 5 is reduced, and the center of the bottom of the second drill bit 5 is provided with a second drill tooth 56.

A plurality of first drill teeth 41 are arranged on the outer side surface of the first drill bit 4, the plurality of first drill teeth 41 are distributed in a matrix manner, the plurality of first drill teeth 41 are arranged to increase the drilling efficiency, the upper end and the lower end of the inner side of the first drill bit 4 are both provided with a first clamping table 42, one side of the top end of the first clamping table 42 is provided with a third boss 43, the inner side surface of the first drill 4 is symmetrically provided with a fourth boss 44, the fourth boss 44 is matched with the second clamping groove 36, the third protrusion 43 is matched with the first locking groove 351 and the third locking groove 511, so that the movement of the first drill 4 is more stable, the first drill 4 is prevented from being deviated, the first locking groove 351 and the third locking groove 511 have the same structure, 4 medial surface middle part of first drill bit and ejector pad 65 fixed connection, 4 lateral surface bottom of first drill bit have the second oblique angle 45 to fall, avoid 4 stress concentration of first drill bit to improve 4 life of first drill bit in the most advanced of bottom.

The lower extreme axial plane of fifth mounting groove 35, first draw-in groove 351, second draw-in groove 36, sixth mounting groove 51, third draw-in groove 511 and drilling rod 3 all is provided with sliding seal pad 9, avoids the device seepage, causes outside mud just as inside the device, rotate round platform 621 and second mounting groove 12 adaptation, first spacing calorie of platform 622 external diameter equals with rotation round platform 621 external diameter.

The working principle of the invention is as follows:

the drill rod 3 and the connecting rod 1 are fixedly installed through the fixing ring 2, then the rotating shaft 62 is installed in the first fixing groove 114 and connected with the first servo motor 61, then the moving table 63 is installed on the rotating shaft 62, the connecting support 64 and the push block 65 are connected with the moving table 63, the first drill bit 4 is installed and connected with the push block 65, and finally the second drill bit 5 is installed.

In the process of drilling and pulling, the rotating shaft 62 is driven to rotate by controlling the forward and reverse rotation of the first servo motor 61, the rotating shaft 62 drives the moving platform 63 to move up and down, and the moving platform 63 drives the pushing block 65 to push the first drill bit 4 back and forth, so that the diameter change of the first drill bit 4 is realized.

The rotating round table 621 and the first limiting clamping table 622 are arranged on the rotating shaft 62, the rotating round table 621 is matched with the second mounting groove 12, and the outer diameter of the first limiting clamping table 622 is equal to that of the rotating round table 621, so that the rotating shaft 62 is more stable in the rotating process, and the phenomenon that the rotating shaft is deviated to cause movement clamping is avoided; by arranging the first limiting clamping table 622 and the second limiting clamping table 66, the movable table 63 is prevented from moving excessively in the up-and-down moving process to cause part damage; through setting up first sealed pad 7, second sealed pad 8, sliding seal pad 9, third sealed pad 10, fourth sealed pad 100, realize the sealed processing of whole device, avoid outside mud to get into in the device, cause the device to damage. By arranging the guide groove 38 and the guide column 16, the installation of parts is facilitated, and the displacement of the parts caused by installation deviation is avoided; the stress of the first drill bit 4 is prevented from being concentrated at the top end of the bottom by chamfering the second bevel angle 45 at the bottom end of the outer side surface of the first drill bit 4, the service life of the first drill bit 4 is prolonged, meanwhile, the second drill bit 5 is conical, and the shaft surface is provided with a fourth external thread 53, so that the contact surface of the second drill bit 5 with rock debris and soil is increased, the drilling speed is accelerated, and the pressure born by the head of the second drill bit 5 is reduced; set up detachable connecting rod 1, drilling rod 3, first drill bit 4, second drill bit 5 for convenient dismantlement of whole device, installation have been practiced thrift time and resource for the maintenance simultaneously, and replacement part cost reduces, has saved the cost.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is illustrative and explanatory only and is not intended to be exhaustive or to limit the invention to the precise embodiments described, and various modifications, additions, and substitutions may be made by those skilled in the art without departing from the scope of the invention or exceeding the scope of the claims.

Claims

1. The variable-diameter drill bit for oilfield drilling is characterized by comprising a connecting rod (1), a fixing ring (2), a drill rod (3), first drill bits (4), second drill bits (5) and an adjusting mechanism (6), wherein the connecting rod (1) and the drill rod (3) are fixedly installed together through the fixing ring (2), the bottom of the drill rod (3) is in threaded connection with the second drill bits (5), four first drill bits (4) are installed between the second drill bits (5) and the drill rod (3) in a matched mode, the four first drill bits (4) are distributed at equal angles, and the adjusting mechanism (6) is arranged inside the connecting rod (1), the drill rod (3) and the second drill bits (5) in a matched mode;

the adjusting mechanism (6) comprises a first servo motor (61), a rotating shaft (62), a moving platform (63), connecting supports (64), a pushing block (65) and a second limiting clamping table (66), the output shaft of the first servo motor (61) is fixedly connected with the rotating shaft (62), the upper end of the rotating shaft (62) is provided with a rotating round table (621), the bottom end of the rotating shaft (62) is provided with a first limiting clamping table (622), the bottom end of the rotating shaft (62) is positioned below the first limiting clamping table (622) and is provided with a fifth external thread (623), the bottom end of the rotating shaft (62) is positioned below the fifth external thread (623) and is provided with the second limiting clamping table (66) through a first pin, the external thread of the fifth external thread (623) is connected with the moving platform (63), and the moving platform (63) is rotatably connected with four connecting supports (64) through a second pin, the four connecting supports (64) are distributed at equal angles, and the other ends of the connecting supports (64) are rotatably connected to the push block (65) through second pins;

the connecting rod is characterized in that a first connecting table (11) is arranged at the top of the connecting rod (1), a first external thread (111) is arranged on the outer side surface of the first connecting table (11), a first mounting groove (112) is arranged at the top of the first connecting table (11), a first servo motor (61) is fixedly mounted in the first mounting groove (112), a first boss (13) is arranged on the outer side of the middle of the connecting rod (1), a first sealing groove (14) is arranged at the bottom side of the middle of the connecting rod (1), a first sealing gasket (7) is arranged in the first sealing groove (14), a second connecting table (15) is arranged at the bottom of the connecting rod (1), four guide posts (16) are arranged at the bottom of the second connecting table (15), the four guide posts (16) are distributed at equal angles, a second mounting groove (12) is arranged in the connecting rod (1), a first fixing groove (114) is arranged at the top of the, a through hole (113) is formed between the first fixing groove (114) and the first mounting groove (112), the top end of the rotating shaft (62) is rotatably mounted in the first fixing groove (114), an output shaft of the first servo motor (61) penetrates through the through hole (113) to be connected with the top end of the rotating shaft (62), and the rotating circular table (621) is rotatably mounted in the second mounting groove (12);

a second external thread (32) is arranged on the outer side of the top end of the drill rod (3), a second boss (31) is arranged at the top of the drill rod (3), the second boss (31) is connected in a first sealing groove (14) in a clamped mode, the second external thread (32) is in threaded connection with a first internal thread (211) of the fixing ring (2), a third mounting groove (33) is formed in the center of the top of the drill rod (3), a second sealing gasket (8) is placed at the bottom of the third mounting groove (33), the third mounting groove (33) is installed in a matched mode with a second connecting platform (15) of the connecting rod (1), four guide grooves (38) are formed in the bottom of the third mounting groove (33), the four guide grooves (38) are distributed at equal angles, positions correspond to positions of the guide columns (16) one by one to one, a first oblique angle (39) is inverted at the top of the guide grooves (38), and the guide columns (16) are inserted, a second connecting groove (37) is formed at the bottom of the drill rod (3), a second internal thread (371) is formed on the inner groove wall of the second connecting groove (37), a fifth mounting groove (35) is formed in the bottom surface of the middle of the drill rod (3), a first clamping groove (351) is formed in one side of the bottom of the fifth mounting groove (35), eight second clamping grooves (36) are formed in the shaft surface of the bottom end of the drill rod (3), a fourth mounting groove (34) is formed between the second connecting groove (37) and the third mounting groove (33), four first mounting holes (40) are arranged on the wall of the fourth mounting groove (34), the four first mounting holes (40) are distributed at equal angles, the push block (65) is slidably arranged in the first mounting hole (40), a fourth sealing gasket (100) is arranged on the wall of the first mounting hole (40), the first limiting clamping table (622) is rotatably arranged in the fourth mounting groove (34).

2. The variable diameter drill bit for oilfield drilling according to claim 1, wherein a first connecting groove (21) is formed at the bottom end of the fixing ring (2), a first internal thread (211) is formed on the groove wall of the first connecting groove (21), the fixing ring (2) is sleeved on the connecting rod (1), the top surface of the first connecting groove (21) is in contact with the top surface of the first boss (13), four rotating platforms (22) are arranged on the outer side surface of the fixing ring (2), and the four rotating platforms (22) are symmetrically distributed about the center of the fixing ring (2).

3. The variable diameter drill bit for oilfield drilling according to claim 1, wherein a sixth installation groove (51) is formed at the top of the second drill bit (5), a third clamping groove (511) is formed at one side inside the sixth installation groove (51), a third connecting table (52) is arranged at the center of the top of the second drill bit (5), a third external thread (521) is formed at the outer side surface of the third connecting table (52), the second drill bit (5) is in threaded connection with the second internal thread (371) of the drill rod (3) through the third external thread (521), a third sealing gasket (10) is arranged between the top surface of the third connecting table (52) and the bottom of the second connecting groove (37), a seventh installation groove (54) is formed at the center of the third connecting table (52), a second fixing groove (55) is formed at the bottom of the seventh installation groove (54), and the bottom of the rotating shaft (62) is rotatably installed in the second fixing groove (55), the second drill bit (5) is conical, a fourth external thread (53) is formed in the axial surface of the second drill bit, and a second drill tooth (56) is arranged at the center of the bottom of the second drill bit (5).

4. The variable diameter drill bit for oilfield drilling according to claim 1, a plurality of first drill teeth (41) are arranged on the outer side surface of the first drill bit (4), the first drill teeth (41) are distributed in a matrix manner, the upper end and the lower end of the inner side of the first drill bit (4) are respectively provided with a first clamping table (42), a third boss (43) is arranged on one side of the top end of the first clamping table (42), a fourth boss (44) is symmetrically arranged on the inner side surface of the first drill bit (4), the fourth boss (44) is matched with the second clamping groove (36), the third boss (43) is matched with the first clamping groove (351) and the third clamping groove (511), the first clamping groove (351) and the third clamping groove (511) are completely consistent in structure, the middle part of the inner side surface of the first drill bit (4) is fixedly connected with a push block (65), and a second bevel angle (45) is inverted at the bottom end of the outer side surface of the first drill bit (4).

5. The variable-diameter drill bit for oilfield drilling according to claim 3, wherein the fifth mounting groove (35), the first clamping groove (351), the second clamping groove (36), the sixth mounting groove (51), the third clamping groove (511) and the lower end axial surface of the drill rod (3) are provided with sliding sealing gaskets (9), the rotating circular truncated cone (621) is matched with the second mounting groove (12), and the outer diameter of the first limiting clamping table (622) is equal to that of the rotating circular truncated cone (621).