A small-diameter downhole tubing cutting device

Abstract

The application discloses a small-diameter downhole oil pipe cutting device, belongs to the technical field of petroleum engineering equipment, and comprises an upper shell, a lower shell, a driving mechanism one, a central shaft, a positioning and righting mechanism, a driving mechanism two, a driving mechanism three, a cutting mechanism and an electric control unit. The upper shell and the lower shell are arranged in a vertical coaxial mode and are movably connected through the positioning and righting mechanism. The central shaft is arranged on the inner side of the positioning and righting mechanism, the driving mechanism one is arranged in the upper shell, the driving mechanism two and the driving mechanism three are arranged in the lower shell through a motor protection cylinder assembly, the lower end of the central shaft is fixedly connected with the motor protection cylinder assembly, the cutting mechanism is arranged on the inner side of a containing cavity of the central shaft and comprises a cutter fixing seat, an alloy blade and a linkage assembly, the driving mechanism one drives the cutting mechanism to rotate through the central shaft, and the alloy blade is combined with the feed and the retreat of the alloy blade. The application meets the requirements of small diameter and large torque, has a wide application range, the sealing structure is safe and reliable, the cutting efficiency is greatly improved, and damage to the casing in the well is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil engineering equipment, in particular to a small-diameter downhole oil pipe cutting device. BACKGROUND

[0002] At present, the downhole oil pipe electric cutting device at home and abroad is 54mm in diameter (outer diameter), and the inner diameter of the commonly used oil pipe in oil fields is mostly 62mm. Due to the influence of the environment (such as salinity, scaling, waxing, deformation, bending, etc.) on the oil pipe in the well, the downhole oil pipe cutting device with an outer diameter of 54mm often encounters resistance and sticking during the downhole process, and the success rate is only about 20-25%, which cannot meet the needs of field construction. In addition, the inner diameter of a part of the oil pipe is 50mm, and the inner diameter of the drill pipe used for oil well overhaul is 53mm. Therefore, the existing 54mm diameter electric cutting device at home and abroad cannot meet the use requirements. The diameter of the existing downhole oil pipe electric cutting device cannot be reduced, mainly because the internal cable occupies space, or a groove is milled on the outer circle of the device. If the internal diameter of the electric cutting device is reduced, the power of the internal motor cannot meet the use requirements, in addition, after the diameter is reduced, the structure size of the feed and retreat cannot meet the requirements. Therefore, the outer diameter size of the existing electric cutting device cannot be reduced, resulting in narrow application range and low working efficiency. Therefore, the existing technology needs to be further improved and improved. SUMMARY

[0003] In view of the above problems of the prior art, the purpose of the present application is to provide a small-diameter downhole oil pipe cutting device to solve the problems of large outer diameter size, narrow application range, poor sealing performance in downhole operation environment and low cutting efficiency of the existing oil pipe electric cutting device.

[0004] In order to solve the above technical problems, the technical scheme adopted by the present application is:

[0005] A small-diameter downhole oil pipe cutting device, comprising an upper housing, a lower housing, a driving mechanism one, a center shaft, a positioning and centralizing mechanism, a driving mechanism two, a driving mechanism three, a cutting mechanism and an electric control unit, the upper housing and the lower housing are both hollow rod body structures and are arranged vertically coaxially.

[0006] The upper end of the lower housing is movably connected to the lower end of the upper housing through the positioning and centralizing mechanism, and a square notch is formed in the upper part of the side wall of the lower housing.

[0007] The center shaft is located on the inner side of the positioning and centralizing mechanism, the upper end of the center shaft is inserted into the interior of the upper housing and movably and sealingly matched with the upper housing, the lower end of the center shaft is inserted into the interior of the lower housing and slidably matched with the lower housing, the driving mechanism one is arranged in the interior of the upper housing, and the output end of the driving mechanism one drives the center shaft to rotate through a shaft sleeve.

[0008] The driving mechanism two and the driving mechanism three are arranged inside the lower housing through the motor cylinder assembly, and are arranged oppositely, the upper end of the motor cylinder assembly is connected with the lower part of the central shaft through the wire passing assembly, and the side wall of the lower housing is linearly and slidingly connected with the motor cylinder assembly.

[0009] In addition, the positioning and righting mechanism comprises a positioning support assembly and a righting support assembly, the positioning support assembly is located above the righting support assembly, and the opposite ends of the two are fixedly connected through bearing top sleeves, the upper end of the positioning support assembly is fixedly and sealingly connected with the lower end of the upper housing, and the upper end of the lower housing is rotationally connected with the lower end of the righting support assembly.

[0010] The output end of the driving mechanism three is connected with the lower end of the lower housing through the transmission mechanism one, and drives the lower housing to move along the axial direction of the motor cylinder assembly, so that the positioning support assembly and the righting support assembly are expanded outward or contracted inward in sequence.

[0011] The lower part of the central shaft has a containing cavity, and the cutting mechanism is arranged inside the containing cavity, which comprises a cutter fixing seat, an alloy blade and a linkage assembly, the cutter fixing seat is slidingly arranged at the upper part of the containing cavity, the alloy blade is detachably fixed on the cutter fixing seat, and the linkage assembly is located at the lower side of the cutter fixing seat.

[0012] The output end of the driving mechanism two is connected with the linkage assembly through the transmission mechanism two, and the cutter fixing seat and the alloy blade are driven by the linkage assembly to extend to the outside of the lower housing or be accommodated in the lower housing.

[0013] Further, the upper housing comprises a circuit board cylinder, a motor cylinder one, a reducer cylinder and a bearing seat arranged coaxially from top to bottom.

[0014] The lower end of the circuit board cylinder is detachably fixedly connected with the upper end of the motor cylinder one through the adapter one, and the circuit board cylinder and the motor cylinder one are sealingly connected with the adapter one.

[0015] The lower end of the motor cylinder one is detachably fixedly connected with the upper end of the reducer cylinder through the adapter two, and the motor cylinder one and the reducer cylinder are sealingly connected with the adapter two.

[0016] The upper end of the bearing seat is fixedly and sealingly connected with the lower end of the reducer cylinder through plug-in connection.

[0017] Further, the inside of the circuit board cylinder is provided with a circuit board support, the driving mechanism one comprises a hollow brushless motor and a hollow planetary gear reducer, and the hollow brushless motor is installed inside the motor cylinder one.

[0018] The hollow planetary gear reducer is arranged inside the reducer sleeve, and the output end of the hollow brushless motor is fixedly connected with the input end of the hollow planetary gear reducer through a hollow shaft coupling.

[0019] The shaft sleeve is located inside the bearing seat and is rotationally matched with the bearing seat through a thrust bearing one. The upper end of the shaft sleeve is connected with the output end of the hollow planetary gear reducer through a torsion sleeve one, and the lower end is coaxially fixedly connected with the upper end of the central shaft. The upper end of the central shaft is rotationally and sealingly matched with the inner wall of the bearing seat.

[0020] Further, the positioning support assembly comprises a hinge support one and a hinge support two. The hinge support one and the hinge support two are both sleeved outside the central shaft. The upper end of the hinge support one is fixedly and sealingly connected with the lower end of the bearing seat through a sealing sleeve. A sealing ring one is arranged between the central shaft and the inner wall of the sealing sleeve.

[0021] The hinge support two is located below the hinge support one. The corresponding ends of the hinge support one and the hinge support two are movably connected through a plurality of groups of support structures which are uniformly distributed in a ring shape.

[0022] Each group of support structures comprises an upper support arm and a lower support arm. The upper end of the upper support arm one is hingedly connected with the hinge support one. The lower end of the upper support arm one is hingedly connected with the upper end of the lower support arm two. The lower end of the lower support arm two is hingedly connected with the hinge support two.

[0023] Further, the righting support assembly comprises a hinge support three and a hinge support four. The hinge support three and the hinge support four are also both sleeved outside the central shaft. The hinge support three and the hinge support two are the same in structure and are symmetrically arranged above and below the bearing top sleeve. Each hinge support is rotationally matched with the central shaft through a rolling bearing on the inner side thereof.

[0024] In addition, the corresponding ends of the hinge support three and the hinge support four are movably connected through the same plurality of groups of support structures. A torsion spring is arranged at the hinged connection between the lower end of each lower support arm two of the righting support assembly and the hinge support four.

[0025] The upper end of the lower housing is fixedly provided with a short top sleeve. The upper part of the short top sleeve is inserted into the inner side of the hinge support four and is rotationally matched with the hinge support four. The upper end of the short top sleeve is provided with a thrust bearing two.

[0026] Further, the motor sleeve assembly comprises a motor sleeve two and a motor sleeve three. The lower end of the motor sleeve two is detachably fixedly connected with the upper end of the motor sleeve three through an adapter three. The motor sleeve two and the motor sleeve three are sealingly matched with the adapter three.

[0027] The driving mechanism three comprises a direct-current speed reduction motor one. The direct-current speed reduction motor one is fixedly arranged inside the motor sleeve three. The lower end of the motor sleeve three is provided with a cylindrical sealing end head. The sealing end head is fixedly and sealingly matched with the inner wall of the motor sleeve three.

[0028] In addition, two guide screws are symmetrically fixed on both sides of the sealing head, two strip-shaped sliding grooves are formed on the lower side wall of the lower shell, and the two guide screws are respectively located in the inner sides of the two strip-shaped sliding grooves.

[0029] Further, the transmission mechanism comprises a lead screw one and a plug screw, the lead screw one is arranged on the inner side of the sealing head through the third thrust bearing and coaxially arranged with the sealing head, and the upper end of the lead screw one is connected with the output end of the first direct-current speed regulation motor through the second torsion sleeve.

[0030] The plug screw is fixed on the lower end of the lower shell, the lower end of the lead screw one is arranged in the inner side of the plug screw, and the lead screw one is coaxially arranged with the plug screw and threadedly matched.

[0031] During operation, the first direct-current speed regulation motor drives the lower shell to slide along the axial direction of the sealing head through the lead screw one.

[0032] The light rod part of the lead screw one is sleeved with a sealing ring two, the inner side of the sealing head is provided with a pressing sleeve, and the sealing ring two is positioned between the lead screw one and the sealing head by the pressing sleeve.

[0033] Further, the wire passing assembly comprises a wire passing sealing sleeve and a wire passing sealing head, the upper end of the wire passing sealing sleeve is sleeved with the outer part of the central shaft and sealingly matched with the central shaft, and the upper end of the motor cylinder assembly is sleeved with the outer part of the wire passing sealing sleeve and sealingly matched with the outer wall of the wire passing sealing sleeve.

[0034] The wire passing sealing head is arranged on the inner side of the wire passing sealing sleeve and coaxially arranged with the wire passing sealing sleeve, the upper end of the wire passing sealing head is sleeved with the lower end of the central shaft and sealingly matched with the central shaft, and the lower end of the wire passing sealing head is sealingly connected with the inner side wall of the wire passing sealing sleeve.

[0035] The inner part of the central shaft has a central hole, the lower part of the wire passing sealing head has a first wire passing hole, and the upper end of the central hole is located at the center of the upper end surface of the central shaft, and the first wire passing hole is communicated with the central hole via the cavity between the wire passing sealing head and the wire passing sealing sleeve.

[0036] The middle side wall of the wire passing sealing sleeve has a second wire passing hole, and the first wire passing hole is communicated with the inner side of the motor cylinder assembly via the second wire passing hole.

[0037] Further, the second driving mechanism comprises a second direct-current speed regulation motor arranged in the motor cylinder assembly, and the upper end of the second direct-current speed regulation motor is fixedly connected with the lower end of the wire passing sealing head through a fixing sleeve.

[0038] The second transmission mechanism comprises a lead screw two arranged on the inner side of the wire passing sealing head, the lower end of the lead screw two is connected with the output end of the second direct-current speed regulation motor through a third torsion sleeve, and the wire passing sealing head is rotationally and sealingly matched with the light rod part of the lead screw two through a sealing ring three.

[0039] Further, the upper side wall of the accommodating cavity is provided with two linear sliding grooves arranged oppositely, and the cutter fixing seat is located in the linear sliding grooves and linearly slides along the radial direction of the central shaft.

[0040] The linkage assembly comprises a driving block and a linkage block, the driving block is slidingly arranged in the accommodating cavity, the upper end of the second screw rod is arranged in the interior of the driving block and is threadedly connected with the driving block, and the second DC motor drives the driving block to move along the axial direction of the central shaft through the second screw rod.

[0041] The linkage block is in L-shaped structure and is arranged in the mounting groove arranged on the upper portion of the driving block, the middle portion of the linkage block is rotationally connected with the side wall of the accommodating cavity through a fixing shaft, one end of the linkage block is slidingly connected with the driving block through a pin shaft, and the other end of the linkage block is slidingly connected with the cutter fixing seat through another pin shaft.

[0042] By adopting the above technical scheme, the motor has small diameter and large power, can be arranged in the oil pipe with a diameter of 40 mm, has a thin stainless steel pipe in the hollow shaft of the motor, and can realize reliable power supply and communication through cable protection under the condition that the motor keeps high-speed rotation (6500 revolutions per minute). The pipe diameter of the motor is small, the torque of the transmission part is large, the requirements of small diameter and large torque are met, the large outer diameter can be cut, the oil pipe with an inner diameter of 76 mm (an outer diameter of 89 mm) can be cut, the oil pipe with an inner diameter of 62 mm (an outer diameter of 73 mm) and the oil well repair drill pipe with an inner diameter of 53 mm (an outer diameter of 73 mm) can be cut, the application range is wide, the success rate of downhole cutting is high, and the success rate is as high as 90% or more. The sealing structure of the motor is safe and reliable, can withstand high pressure of 80 MPa, avoids damage of electrical equipment in the device, the cutting mechanism accurately controls the linear feeding and retracting of the alloy blade along the radial direction through the linkage assembly during the working process, the cutting precision is high, the working efficiency is greatly improved, and damage to the casing in the well can be effectively avoided. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a structural schematic view of a small-diameter downhole oil pipe cutting device.

[0044] Figure 2 is a top view of the small-diameter downhole oil pipe cutting device.

[0045] Figure 3 is Figure 2 is a sectional view of the small-diameter downhole oil pipe cutting device along the A-A direction.

[0046] Figure 4 is a structural schematic view of a lower shell.

[0047] Figure 5is the structural schematic diagram of the central shaft of the application.

[0048] Figure 6 is the combined structural schematic diagram of the positioning and righting mechanism, the central shaft and the related parts of the application.

[0049] Figure 7 is the structural schematic diagram of the short top sleeve of the application.

[0050] Figure 8 is the combined structural schematic diagram of the transmission mechanism one, the motor cylinder three, the sealing end head and the related parts of the application.

[0051] Figure 9 is the schematic diagram of the combined body of the transmission mechanism one, the sealing end head and the related parts of the application

[0052] Figure 10 is the structural exploded view of the wire passing assembly of the application.

[0053] Figure 11 is the structural schematic diagram of the combined body of the lead screw two and the cutting mechanism of the application.

[0054] Figure 12 is Figure 11 is the exploded view of the combined body shown.

[0055] As shown in the figure: 1, the upper shell; 11, the circuit board sleeve; 111, the circuit board support; 12, the motor sleeve one; 13, the reducer sleeve; 14, the bearing seat; 15, the adapter one; 16, the adapter two; 17, the sealing sleeve; 18, the sealing ring one; 2, the lower shell; 21, the square notch; 22, the short top sleeve; 23, the thrust bearing two; 24, the motor sleeve two; 25, the motor sleeve three; 26, the adapter three; 27, the sealing end; 271, the guide screw; 28, the strip sliding groove; 3, the center shaft; 31, the bearing top sleeve; 32, the shaft sleeve; 33, the thrust bearing one; 34, the containing cavity; 341, the straight line sliding groove; 35, the wire sealing sleeve; 351, the second wire hole; 36, the wire sealing head; 361, the first wire hole; 37, the sealing ring three; 38, the center hole; 4, the cutting mechanism; 41, the cutter fixed seat; 42, the alloy blade; 43, the driving block; 431, the mounting groove; 432, the axial sliding groove; 433, the radial sliding groove; 44, the linkage block; 441, the long circular hole; 45, the fixed shaft; 46, the pin shaft one; 47, the pin shaft two; 5, the positioning support assembly; 51, the hinge support one; 52, the hinge support two; 53, the upper support arm; 54, the lower support arm; 6, the centralizing support assembly; 61, the hinge support three; 62, the hinge support four; 71, the hollow brushless motor; 72, the hollow planetary gear reducer; 73, the hollow shaft coupling; 74, the torsion sleeve one; 81, the DC speed reducer one; 82, the screw one; 83, the plug; 84, the torsion sleeve two; 85, the sealing ring two; 86, the compression sleeve; 87, the thrust bearing three; 88, the bearing gland; 91, the DC speed reducer two; 93, the screw two; 94, the torsion sleeve three; 95, the fixed sleeve; 96, the Hall element; 97, the magnetic steel; 10, the sliding needle seat. DETAILED DESCRIPTION

[0056] In order to make the advantages, technical solutions of the present application more clear, explicit, below for specific examples of the present application are described in detail.

[0057] Embodiment, combined Figures 1 to 12 A small diameter downhole tubing cutting device, comprising an upper shell 1, a lower shell 2, a driving mechanism one, a center shaft 3, a positioning centralizing mechanism, a driving mechanism two, a driving mechanism three, a cutting mechanism 4 and an electric control unit, the upper shell 1 and the lower shell 2 are both hollow rod structure, and are arranged vertically coaxially. The upper shell 1 comprises a circuit board sleeve 11, a motor sleeve one 12, a reducer sleeve 13 and a bearing seat 14 arranged coaxially from top to bottom, the circuit board sleeve 11, the motor sleeve one 12, the reducer sleeve 13 and the bearing seat 14 all adopt stainless steel pipes with same outer diameter size, the lower shell 2 also adopts stainless steel pipe with same outer diameter size, and the lower end surface adopts chamfer structure.

[0058] The inside of the circuit board sleeve 11 is fixedly provided with a circuit board support 111, and the lower end of the circuit board sleeve 11 is detachably fixedly connected with the upper end of the motor sleeve 12 through an adapter 15, and the circuit board sleeve 11 and the motor sleeve 12 are sealingly matched with the adapter 15.

[0059] The lower end of the motor sleeve 12 is detachably fixedly connected with the upper end of the speed reducer sleeve 13 through an adapter 16, and the motor sleeve 12 and the speed reducer sleeve 13 are sealingly matched with the adapter 16, and the upper end of the bearing seat 14 is fixedly connected with the lower end of the speed reducer sleeve 13 in a plug-in and sealing manner. The upper and lower ends of the adapter 15 and the adapter 16 are both provided with external threads and annular grooves, and sealing rings are arranged in the annular grooves.

[0060] The electric control unit comprises a Hall element 96, a magnetic steel 97 and a PLC controller, the PLC controller is fixedly installed on the circuit board support 111, and the upper and lower ends of the circuit board support 111 are both provided with wire holes, and wire plugs are arranged in the wire holes.

[0061] The upper end of the circuit board sleeve 11 is detachably provided with a sliding pin seat 10, the lower end of the sliding pin seat 10 is sealingly matched with the circuit board sleeve 11 in a threaded manner, and the upper housing 1 is fixedly connected with the executing end of the logging cable winding and unwinding device through the sliding pin seat 10, and the logging cable winding and unwinding device can preferably adopt a logging cable winch. During work, the cutting device is lowered into the inside of the downhole tubing through the logging cable winding and unwinding device, and can reach a depth of several kilometers.

[0062] The upper end of the lower housing 2 is movably connected with the lower end of the upper housing 1 through the positioning and righting mechanism, and a square notch 21 is formed in the upper side wall of the lower housing 2. The center shaft 3 is located on the inner side of the positioning and righting mechanism, the upper end of the center shaft 3 is inserted into the inside of the upper housing 1 and sealingly matched with the upper housing 1 in a rotating manner, and the lower end of the center shaft 3 is inserted into the inside of the lower housing 2 and axially slidably matched with the lower housing 2. During work, the center shaft 3 drives the lower housing 2 to rotate synchronously.

[0063] Specifically, the positioning and righting mechanism comprises a positioning support assembly 5 and a righting support assembly 6, the positioning support assembly 5 is located above the righting support assembly 6, the opposite ends of the positioning support assembly 5 and the righting support assembly 6 are fixedly connected through a bearing top sleeve 31, the bearing top sleeve 31 is made of beryllium copper, the center shaft 3 is located on the inner side of the bearing top sleeve 31, and the center shaft 3 is rotatably matched with the inner wall of the bearing top sleeve 31. The upper end of the positioning support assembly 5 is fixedly and sealingly connected with the lower end of the upper housing 1, and the upper end of the lower housing 2 is rotatably connected with the lower end of the righting support assembly 6.

[0064] The positioning support assembly 5 comprises a hinge support one 51 and a hinge support two 52, both of which are sleeved outside the central shaft 3, the upper end of the hinge support one 51 is fixedly connected with the lower end of the bearing seat 14 through a sealing sleeve 17, a sealing ring one 18 is arranged between the central shaft 3 and the inner wall of the sealing sleeve 17, the central shaft 3 is in rotating fit with the sealing sleeve 17 and the hinge support one 51, and rotating sealing is formed between the sealing ring one 18 and the sealing sleeve 17, so that water in the oil pipe is effectively prevented from entering the inside of the upper housing 1 through the gap between the hinge support one 51 and the outer wall of the central shaft 3.

[0065] The hinge support two 52 is located below the hinge support one 51, and the corresponding ends of the hinge support one 51 and the hinge support two 52 are movably connected through four groups of support structures which are uniformly distributed in a ring shape. Each group of support structures comprises an upper support arm 53 and a lower support arm 54, the upper end of the upper support arm 53 one is hingedly connected with the hinge support one 51, the lower end of the upper support arm 53 one is hingedly connected with the upper end of the lower support arm 54 two, and the lower end of the lower support arm 54 two is hingedly connected with the hinge support two 52. When the four groups of support structures are in a folded state, the inner sides of the upper support arm 53 and the lower support arm 54 are close to or close to the circumferential outer wall of the central shaft, and the three hinge points are respectively located at the three corners of the isosceles triangle.

[0066] Under the action of the axial force, the hinge support two 52 moves along the axial direction of the central shaft 3 relative to the hinge support one 51, when the hinge support two 52 moves upward, the four groups of support structures are all expanded outward and clamped on the inner side wall of the downhole oil pipe, so that the cutting device is fixed inside the downhole oil pipe. When the hinge support two 52 moves downward, the four groups of support structures are all folded inward, and are separated from the inner side wall of the downhole oil pipe, so that the cutting device is conveniently lowered or taken out inside the downhole oil pipe.

[0067] Similarly, the centralizing support assembly 6 comprises a hinge support three 61 and a hinge support four 62, both of which are also sleeved outside the central shaft 3, the hinge support three 61 and the hinge support two 52 are the same in structure and are symmetrically arranged above and below the bearing top sleeve 31, and each hinge support is in rotating fit with the central shaft 3 through the rolling bearing on the inner side thereof. The opposite ends of the hinge support three 61 and the hinge support two 52 are fixedly connected through the bearing top sleeve 31, so as to realize linkage.

[0068] In addition, the corresponding ends of the hinge support three 61 and the hinge support four 62 are movably connected through the same four groups of support structures, and a torsional spring is arranged at the hinge connection between each lower support arm 54 two of the centralizing support assembly 6 and the hinge support four 62. When not subjected to the axial force, the torsional spring keeps the four groups of support structures between the hinge support three 61 and the hinge support four 62 in a folded state.

[0069] In the working state, when the cutting device is lowered to the set depth inside the oil pipe, the lower shell 2 drives the hinge support four 62 to move upward along the axial direction of the central shaft 3, the hinge support four 62 drives the hinge support two 52 to move upward synchronously through the bearing top sleeve 31, the four sets of support structures on the top are first expanded and clamped on the inner wall of the oil pipe, at this time, the hinge support two 52, the hinge support three 61 and the bearing top sleeve 31 stop moving, then the hinge support four 62 continues to move upward along the central shaft 3, the four sets of support structures on the bottom are expanded and clamped on the inner wall of the downhole oil pipe, the cutting device is righted and coaxial with the downhole oil pipe, and eight support points in the embodiment are firmly fixed inside the downhole oil pipe.

[0070] The upper end of the lower shell 2 is fixedly provided with a short top sleeve 22, the upper part of the short top sleeve 22 is inserted into the inner side of the hinge support four 62 and rotationally matched with the hinge support four 62, and the upper end of the short top sleeve 22 is provided with a thrust bearing two 23. An annular positioning groove 221 is formed in the circumferential outer wall of the short top sleeve 22, and a anti-disengagement pin is detachably fixed on the side wall of the hinge support four 62, the end of the anti-disengagement pin is located in the annular positioning groove 221, so that the lower shell 2 is rotationally connected with the hinge support four 62 through the short top sleeve 22, and the short top sleeve 22 and the hinge support four 62 are prevented from being disengaged in the axial direction.

[0071] The driving mechanism one is arranged in the inside of the upper shell 1, and the output end of the driving mechanism one drives the central shaft 3 to rotate through a shaft sleeve 32. Specifically, the driving mechanism one comprises a hollow brushless motor 71 and a hollow planetary gear reducer 72, the hollow brushless motor 71 is installed in the inside of the motor cylinder one 12, and a stainless steel threading pipe is arranged in the output shaft of the hollow brushless motor 71. The hollow planetary gear reducer 72 preferably adopts a four-stage planetary gear reducer, the hollow planetary gear reducer 72 is used to reduce the rotating speed of the central shaft 3 and increase the torque, each central gear of the hollow planetary gear reducer 72 is a hollow gear shaft, and the stainless steel threading pipe is arranged in the inside of each hollow gear shaft. The hollow planetary gear reducer 72 is arranged in the inside of the reducer cylinder 13, the outer gear cylinder of the hollow planetary gear reducer 72 and the reducer cylinder 13 are integrated, and the output end of the hollow brushless motor 71 is fixedly connected with the input end of the hollow planetary gear reducer 72 through a hollow shaft coupling 73.

[0072] The shaft sleeve 32 is located in the inside of the bearing seat 14 and rotationally matched with the bearing seat 14 through a thrust bearing one 33, the upper end of the shaft sleeve 32 is connected with the output end of the hollow planetary gear reducer 72 through a torsion sleeve one 74, the lower end of the shaft sleeve 32 is fixedly connected with the upper end of the central shaft 3 in a coaxial manner, and the upper end of the central shaft 3 is rotationally and sealingly matched with the inner wall of the bearing seat 14. The lower end of the stainless steel threading pipe is arranged in the central hole 38 of the central shaft 3, and the upper end of the stainless steel threading pipe is connected with a conductive slip ring in the adapter one 15.

[0073] The driving mechanism two and the driving mechanism three are arranged inside the lower housing 2 through the motor barrel assembly, and are arranged oppositely, the upper end of the motor barrel assembly is connected with the lower part of the central shaft 3 through the wire passing assembly and fixed sealing, and the side wall of the lower housing 2 is linearly slidingly matched with the circumferential outer wall of the motor barrel assembly.

[0074] Specifically, the motor barrel assembly comprises a motor barrel two 24 and a motor barrel three 25, the motor barrel two 24 and the motor barrel three 25 are stainless steel straight pipe bodies with the same outer diameter size, the upper end of the motor barrel two 24 is fixedly connected with the lower end of the central shaft 3, the lower end of the motor barrel two 24 is detachably fixedly connected with the upper end of the motor barrel three 25 through an adapter three 26, the motor barrel two 24 and the motor barrel three 25 are sealingly matched with the adapter three 26, the upper and lower ends of the adapter three 26 are also provided with external threads and annular grooves on the circumferential outer wall, and the same sealing rings are arranged in the annular grooves.

[0075] The output end of the driving mechanism three is connected with the lower end of the lower housing 2 through a transmission mechanism one, and drives the lower housing 2 to move along the axial direction of the motor barrel assembly relative to the motor barrel assembly, so as to realize that the positioning support assembly 5 and the centralizing support assembly 6 are expanded outward or contracted inward in sequence.

[0076] Specifically, the driving mechanism three comprises a DC speed reduction motor one 81, the DC speed reduction motor one 81 is fixedly installed inside the motor barrel three 25 through a bearing gland 88, a cylindrical sealing end head 27 is fixedly installed at the lower end of the motor barrel three 25, and a sealing ring is arranged between the sealing end head 27 and the inner wall of the motor barrel three 25 and is fixedly matched in a threaded connection manner.

[0077] In addition, two guide screws 271 are symmetrically fixed on the two sides of the sealing end head 27, two strip-shaped sliding grooves 28 are formed on the lower part of the side wall of the lower housing 2, and the two guide screws 271 are respectively located inside the two strip-shaped sliding grooves 28, and the outer diameter size of the guide screw 271 is matched with the width of the strip-shaped sliding groove 28.

[0078] The transmission mechanism one comprises a lead screw one 82 and a plug 83, the lead screw one 82 is installed inside the sealing end head 27 through a thrust bearing three 87 and is coaxially arranged with the sealing end head 27, and the upper end of the lead screw one 82 is connected with the output end of the DC speed reduction motor one 81 through a torsion sleeve two 84.

[0079] The screw plug 83 is fixedly embedded in the lower end of the lower housing 2, the lower part of the screw plug 83 has a conical outer wall, a threaded hole coaxial with the screw plug 83 is formed in the screw plug 83, the lower end of the screw rod one 82 is arranged in the inner side of the screw plug 83, the screw rod one 82 is coaxially arranged with the screw plug 83, and the threaded segment of the screw rod one 82 is threadedly connected with the screw plug 83. In operation, the DC speed reducer one 81 drives the lower housing 2 to slide along the axial direction of the sealing end 27 through the screw rod one 82, and drives the hinge support four 62 to move along the axial direction of the central shaft 3.

[0080] The light rod part of the screw rod one 82 is sleeved with a sealing ring two 85, the inner side of the sealing end 27 is provided with a pressing sleeve 86, the pressing sleeve 86 positions the sealing ring two 85 between the screw rod one 82 and the sealing end 27, the sealing ring two 85 realizes the rotary sealing between the screw rod one 82 and the sealing end 27, and effectively prevents water in the lower oil pipe from entering the inside of the motor protector assembly through the space between the sealing end 27 and the outer wall of the screw rod one 82.

[0081] The lower part of the central shaft 3 has a through accommodating cavity 34, and the cutting mechanism 4 is arranged in the inner side of the accommodating cavity 34 and includes a cutter fixing seat 41, a alloy blade 42 and a linkage assembly. The cutter fixing seat 41 is slidably arranged in the upper part of the accommodating cavity 34. Specifically, the upper part of the accommodating cavity 34 has two opposite linear sliding grooves 341 in the side wall, the cutter fixing seat 41 is located in the linear sliding grooves 341 and linearly slides along the radial direction of the central shaft 3. The alloy blade 42 is fastened to the groove of the cutter fixing seat 41 through a threaded pin, the cutting edge of the alloy blade 42 faces one side of the square notch 21, and the linkage assembly is located on the lower side of the cutter fixing seat 41.

[0082] The output end of the driving mechanism two is connected with the linkage assembly through the transmission mechanism two, and the cutter fixing seat 41 and the alloy blade 42 are driven by the linkage assembly to extend to the outside of the lower housing 2 or be accommodated in the lower housing 2 through the square notch 21.

[0083] Specifically, the wire passing assembly includes a wire passing sealing sleeve 35 and a wire passing sealing head 36. The upper end of the wire passing sealing sleeve 35 is sleeved with the outer part of the central shaft 3 and sealingly connected with the outer wall of the central shaft 3. The upper end of the motor protector assembly is sleeved with the outer part of the wire passing sealing sleeve 35 and sealingly connected with the outer wall of the wire passing sealing sleeve 35. The wire passing sealing head 36 is arranged in the inner side of the wire passing sealing sleeve 35 and coaxially arranged with the wire passing sealing sleeve 35. The upper end of the wire passing sealing head 36 is sleeved with the lower end of the central shaft 3 and sealingly connected with the lower end of the central shaft 3. The lower end of the wire passing sealing head 36 is sealingly connected with the inner side wall of the wire passing sealing sleeve 35.

[0084] The center hole 38 has a first wire hole 361 in the lower part of the wire sealing head 36, and the upper end of the center hole 38 is located at the center of the upper end surface of the center shaft 3, and the first wire hole 361 communicates with the center hole 38 through the cavity between the wire sealing head 36 and the wire sealing sleeve 35. The middle part of the wire sealing sleeve 35 has a second wire hole 351 in the side wall, and the first wire hole 361 communicates with the inner side of the motor cylinder assembly through the second wire hole 351.

[0085] The driving mechanism two includes a DC speed reduction motor two 91 located in the motor cylinder assembly, and the lower end of the DC speed reduction motor two 91 is fixed to the inner side of the motor cylinder two 24 through a motor support 911. The upper end of the DC speed reduction motor two 91 is fixedly connected with the lower end of the wire sealing head 36 through a fixing sleeve 95.

[0086] Specifically, the transmission mechanism two includes a lead screw two 93 arranged in the inner side of the wire sealing head 36, and the lower end of the lead screw two 93 is coaxially connected with the output shaft of the DC speed reduction motor two 91 through a torsion sleeve three 94. A Hall element 96 is fixedly installed on the fixing sleeve 95, and the signal end of the Hall element 96 is connected with the PLC controller in communication. The magnet steel 97 is fixed on the side wall of the lead screw two 93 and corresponds to the Hall element 96. The Hall element 96 records the rotation angle of the lead screw two 93 through the magnet steel 97 and transmits the data to the PLC controller in real time. In addition, the inner part of the wire sealing head 36 is provided with a sealing ring three 37, which is in rotating sealing cooperation with the light rod part of the lead screw two 93.

[0087] Specifically, the wire assembly is used to connect the center shaft 3 and the motor cylinder assembly, so that the center shaft 3 drives the lower shell 2, the motor cylinder assembly and the structures inside the motor cylinder assembly to rotate synchronously with the cutting mechanism 4. At the same time, the center hole 38, the first wire hole 361 and the second wire hole 351 realize the cable passing of the electrical part inside the motor cylinder assembly, and are electrically connected with the circuit structure inside the circuit board cylinder 11. In addition, the sealing ring three 37 in the inner part of the wire sealing head 36 can realize the rotating sealing between the wire sealing head 36 and the lead screw two 93, so as to avoid the water in the downhole oil pipe from entering the inner part of the motor cylinder assembly through the wire sealing head 36 and the lead screw two 93.

[0088] The linkage assembly includes a driving block 43 and a linkage block 44. The driving block 43 is slidingly arranged in the accommodating cavity 34, and the rear part of the driving block 43 has a threaded through hole which communicates with the accommodating cavity 34. The upper end of the lead screw two 93 is arranged in the threaded through hole of the driving block 43 and is threadedly connected with the driving block 43. The DC speed reduction motor two 91 drives the driving block 43 to move linearly along the axis of the center shaft 3 through the lead screw two 93.

[0089] The cutter fixing base 41, the driving block 43 and the linkage block 44 are all made of beryllium copper, the linkage block 44 is L-shaped structure, and is located in the installation groove 431 of the upper part of the driving block 43, the axial sliding groove 432 and the radial sliding groove 433 are arranged on the two sides of the driving block 43. The middle part of the linkage block 44 is provided with the fixed shaft 45, the fixed shaft 45 is located in the inner side of the axial sliding groove 432, and the two ends of the fixed shaft 45 are fixedly connected with the side walls of the installation groove 431, and the linkage block 44 is rotationally connected with the fixed shaft 45.

[0090] One end of the linkage block 44 is provided with the pin shaft one 46, the two ends of the pin shaft one 46 are located in the radial sliding grooves 433 on the two sides, and are in sliding connection with the driving block 43, and the driving block 43 drives the linkage block 44 to rotate around the fixed shaft 45 through the pin shaft one 46. In addition, the other end of the linkage block 44 is provided with the long circular hole 441, the long circular hole 441 is provided with the pin shaft two 47, the two ends of the pin shaft two 47 are fixedly connected with the inner wall of the cavity of the cutter fixing base 41, and are in sliding connection with the side wall of the long circular hole 441, when the linkage block 44 rotates around the fixed shaft 45, the linkage block 44 drives the cutter fixing base 41 and the alloy blade 42 to make linear feeding motion along the radial direction of the central shaft 3 through the pin shaft two 47.

[0091] The parts not described in the application can be realized by using or referring to the existing technology.

[0092] In addition, the terms "first", "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance.

[0093] In the description of the application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0094] Of course, the above description is not a limitation of the application, and the application is not limited to the above examples, and the changes, modifications, additions or replacements made by the person skilled in the art within the essential scope of the application should also belong to the protection scope of the application.

Claims

1. A small-diameter downhole tubing cutting device, characterized in that, It includes an upper shell (1), a lower shell (2), a drive mechanism one, a central shaft (3), a positioning and straightening mechanism, a drive mechanism two, a drive mechanism three, a cutting mechanism (4), and an electrical control unit. The upper shell (1) and the lower shell (2) are both hollow rod structures and are arranged vertically coaxially. The upper end of the lower shell (2) is movably connected to the lower end of the upper shell (1) through the positioning and straightening mechanism. A square slot (21) is provided on the upper side wall of the lower shell (2). The central shaft (3) is located inside the positioning and straightening mechanism. Its upper end is inserted into the interior of the upper outer shell (1) and is in a movable sealing fit with it. The lower end of the central shaft (3) is inserted into the interior of the lower outer shell (2) and is in a sliding fit with it. The driving mechanism is located inside the upper outer shell (1), and its output end drives the central shaft (3) to rotate through the bushing (32). The second and third drive mechanisms are located inside the lower outer shell (2) through the motor sleeve assembly, and are arranged opposite to each other, one above the other. The upper end of the motor sleeve assembly is sealed to the lower part of the central shaft (3) through the wire guide assembly. The side wall of the lower outer shell (2) is linearly slidingly engaged with the motor sleeve assembly. In addition, the positioning and straightening mechanism includes a positioning support assembly (5) and a straightening support assembly (6). The positioning support assembly (5) is fixedly connected to the straightening support assembly (6) located below through a bearing top sleeve (31). The upper end of the positioning support assembly (5) is fixedly and sealed to the lower end of the upper outer shell (1), and the upper end of the lower outer shell (2) is rotatably connected to the lower end of the straightening support assembly (6). The output end of the drive mechanism three is connected to the lower end of the lower shell (2) through the transmission mechanism one, and drives the lower shell (2) to move along its axial direction relative to the motor sleeve assembly, so that the positioning support assembly (5) and the straightening support assembly (6) are successively opened to the outside or closed to the inside. The lower part of the central shaft (3) has a receiving cavity (34), and the cutting mechanism (4) is located inside the receiving cavity (34). It includes a tool holder (41), an alloy blade (42) and a linkage assembly. The tool holder (41) is slidably located on the upper part of the receiving cavity (34), and the alloy blade (42) is detachably fixed on the tool holder (41). The linkage assembly is located on the lower side of the tool holder (41). The output end of the second drive mechanism is connected to the linkage component through the second transmission mechanism, and the linkage component drives the tool holder (41) and the alloy blade (42) to extend to the outside of the lower housing (2) or be stored inside the lower housing (2) through the square slot (21).

2. The small-diameter downhole tubing cutting device according to claim 1, characterized in that, The upper outer casing (1) includes a circuit board sleeve (11), a motor sleeve (12), a reducer sleeve (13), and a bearing seat (14) arranged coaxially from top to bottom. The lower end of the circuit board sleeve (11) is detachably and fixedly connected to the upper end of the motor sleeve (12) via an adapter (15). Both the circuit board sleeve (11) and the motor sleeve (12) are sealed to the adapter (15). The lower end of the motor casing (12) is detachably and fixedly connected to the upper end of the reducer casing (13) via the adapter (16). Both the motor casing (12) and the reducer casing (13) are sealed to the adapter (16). The upper end of the bearing housing (14) is inserted and fixedly connected to the lower end of the reducer casing (13) and sealed.

3. The small-diameter downhole tubing cutting device according to claim 2, characterized in that, The circuit board sleeve (11) is provided with a circuit board bracket (111) inside. The drive mechanism includes a hollow brushless motor (71) and a hollow planetary gear reducer (72). The hollow brushless motor (71) is installed inside the motor sleeve (12). The hollow planetary gear reducer (72) is located inside the reducer casing (13), and the output end of the hollow brushless motor (71) is fixedly connected to the input end of the hollow planetary gear reducer (72) through the hollow shaft coupling (73). The bushing (32) is located inside the bearing housing (14) and is rotatably connected to the bearing housing (14) via a thrust bearing (33). The upper end of the bushing (32) is connected to the output end of the hollow planetary gear reducer (72) via a torque sleeve (74), and its lower end is coaxially fixedly connected to the upper end of the central shaft (3). The upper end of the central shaft (3) is rotatably sealed to the inner wall of the bearing housing (14).

4. The small-diameter downhole tubing cutting device according to claim 2, characterized in that, The positioning support assembly (5) includes hinge support one (51) and hinge support two (52). Both hinge support one (51) and hinge support two are sleeved on the outside of the central shaft (3). The upper end of hinge support one (51) is fixedly and sealed to the lower end of the bearing seat (14) through a sealing sleeve (17). A sealing ring one (18) is provided between the central shaft (3) and the inner wall of the sealing sleeve. Hinge support 2 (52) is located below hinge support 1 (51), and the corresponding ends of hinge support 1 (51) and hinge support 2 (52) are movably connected by multiple sets of support structures that are evenly distributed in a ring. Each set of support structures includes an upper support arm (53) and a lower support arm (54). The upper end of the upper support arm (53) is hinged to the hinge support (51), and its lower end is hinged to the upper end of the lower support arm (54). The lower end of the lower support arm (54) is hinged to the hinge support (52).

5. A small-diameter downhole tubing cutting device according to claim 4, characterized in that, The straightening support assembly (6) includes hinge support three (61) and hinge support four (62). Hinge support three (61) and four are also sleeved on the outside of the central shaft (3). Hinge support three (61) and hinge support two (52) have the same structure and are arranged symmetrically about the bearing top sleeve (31). Each hinge support is rotated with the central shaft (3) through the rolling bearing on its inner side. In addition, the corresponding ends of hinge support three (61) and hinge support four (62) are connected by the same multiple sets of support structures. Each lower support arm (54) of the straightening support assembly (6) is equipped with a torsion spring at the hinge joint between the lower end of the two lower support arms (54) and the hinge support four (62). The upper end of the lower outer shell (2) is fixedly provided with a short top sleeve (22). The upper part of the short top sleeve (22) is inserted into the inner side of the hinge support four (62) and rotates with it. The upper end of the short top sleeve (22) is adjacent to the thrust bearing two (23).

6. The small-diameter downhole tubing cutting device according to claim 1, characterized in that, The motor casing assembly includes a second motor casing (24) and a third motor casing (25). The lower end of the second motor casing (24) is detachably and fixedly connected to the upper end of the third motor casing (25) via an adapter (26). The corresponding ends of the second motor casing (24) and the third motor casing (25) are sealed to the adapter (26). The drive mechanism three includes a DC geared motor one (81), the DC geared motor one (81) is fixed inside the motor casing three (25), and the lower end of the motor casing three (25) is provided with a cylindrical sealing end (27), and the sealing end (27) is fixedly sealed with the inner wall of the motor casing three (25). In addition, two guide screws (271) are symmetrically fixed on both sides of the sealing end (27), and two strip grooves (28) are provided on the lower side wall of the lower outer shell (2), with the two guide screws (271) located inside the two strip grooves (28) respectively.

7. A small-diameter downhole tubing cutting device according to claim 6, characterized in that, The transmission mechanism includes a lead screw (82) and a plug (83). The lead screw (82) is located inside the sealing end (27) via a thrust bearing (87) and is coaxially arranged with the sealing end (27). The upper end of the lead screw (82) is connected to the output end of the DC geared motor (81) via a torque sleeve (84). The plug (83) is fixed at the lower end of the lower housing (2), and the lower end of the screw rod (82) passes through the inside of the plug (83). The screw rod (82) and the plug (83) are arranged coaxially and threaded together. During operation, the DC geared motor (81) drives the lower housing (2) to slide relative to the sealing end (27) along its axial direction via the lead screw (82); The lead screw (82) is fitted with a sealing ring (85) on its smooth part, and a clamping sleeve (86) is provided on the inner side of the sealing end (27). The clamping sleeve (86) positions the sealing ring (85) between the lead screw (82) and the sealing end (27).

8. A small-diameter downhole tubing cutting device according to claim 1, characterized in that, The wire guide assembly includes a wire guide sealing sleeve (35) and a wire guide sealing head (36). The upper end of the wire guide sealing sleeve (35) is sleeved on the outside of the central shaft (3) and sealed with it. The upper end of the motor sleeve assembly is sleeved on the outside of the wire guide sealing sleeve (35) and sealed with the outer wall of the wire guide sealing sleeve (35). The wire sealing head (36) is located inside the wire sealing sleeve (35) and is arranged coaxially with it. The upper end of the wire sealing head (36) is sleeved on the lower end of the central shaft (3) and sealed with it. The lower end of the wire sealing head (36) is fixedly and sealed to the inner wall of the wire sealing sleeve (35). The central shaft (3) has a central hole (38) inside, and the lower part of the wire sealing head (36) has a first wire hole (361). The upper port of the central hole (38) is located at the center of the upper end face of the central shaft (3). The first wire hole (361) communicates with the central hole (38) through the cavity between the wire sealing head (36) and the wire sealing sleeve (35). The middle side wall of the wire sealing sleeve (35) has a second wire hole (351), and the first wire hole (361) communicates with the inner side of the motor sleeve assembly through the second wire hole (351).

9. A small-diameter downhole tubing cutting device according to claim 8, characterized in that, The second drive mechanism includes a second DC geared motor (91) housed in the motor sleeve assembly. The upper end of the second DC geared motor (91) is fixedly connected to the lower end of the wire sealing head (36) via a fixed sleeve (95). The transmission mechanism 2 includes a lead screw 2 (93) located inside the wire sealing head (36). The lower end of the lead screw 2 (93) is connected to the output end of the DC geared motor 2 (91) through a torque sleeve 3 (94). The wire sealing head (36) is rotatably sealed to the smooth part of the lead screw 2 (93) through a sealing ring 3 (37).

10. A small-diameter downhole tubing cutting device according to claim 9, characterized in that, The upper sidewall of the receiving cavity (34) has two oppositely arranged linear slide grooves (341), and the tool fixing seat (41) is located in the linear slide groove (341) and slides linearly with it along the radial direction of the central axis (3). The linkage assembly includes a drive block (43) and a linkage block (44). The drive block (43) is slidably disposed in the receiving cavity (34). The upper end of the lead screw (93) passes through the interior of the drive block (43) and is threadedly engaged with it. The DC geared motor (91) drives the drive block (43) to move relative to the central axis (3) along its axial direction through the lead screw (93). The linkage block (44) has an L-shaped structure and is located in the mounting groove (431) opened on the upper part of the drive block (43). The middle part of the linkage block (44) is rotatably connected to the side wall of the receiving cavity (34) through the fixed shaft (45). One end of the linkage block (44) is slidably engaged with the drive block (43) through the first pin (46), and the other end is slidably engaged with the tool fixing seat (41) through the second pin (47).

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