CN113027345A

CN113027345A - Composite rotary eccentric reaming tool

Info

Publication number: CN113027345A
Application number: CN202110386113.XA
Authority: CN
Inventors: 孔春岩; 黄文星; 朱容军; 赵国尧; 辛红伟; 王涵
Original assignee: Xihua University
Current assignee: Xihua University
Priority date: 2021-04-12
Filing date: 2021-04-12
Publication date: 2021-06-25

Abstract

The invention relates to a composite rotary eccentric reaming tool used in the field of reaming while drilling operation in the petroleum and natural gas industry, which solves the problems of poor recovery safety of the eccentric reaming tool, low reaming efficiency of the reaming while drilling tool and the like. The technical scheme is as follows: the upper end of the upper joint is provided with threads, the lower end of the upper joint is in threaded connection with the upper end of the upper shell, the lower end of the upper shell is in threaded connection with the upper end of the middle shell, the lower end of the middle shell is in threaded connection with the upper end of the lower shell, and the lower end of the lower shell is in threaded connection with the upper end of the middle joint; the lower end of the rotor is in threaded connection with the upper end of the universal shaft, the lower end of the universal shaft is in threaded connection with the upper end of the transmission joint, the lower end of the transmission joint is in threaded connection with the upper end of the upper mandrel, the lower end of the upper mandrel is in threaded connection with the upper end of the lower mandrel, and the lower end of the lower mandrel is in threaded connection with the eccentric drill bit. The invention realizes the compound rotation reaming while drilling of the revolution and the rotation of the eccentric bit, has higher reaming efficiency, is convenient and reliable to recover the eccentric bit after the reaming operation is finished, and overcomes the problem of difficult alignment of the central line of the eccentric bit.

Description

Composite rotary eccentric reaming tool

Technical Field

The invention relates to a composite rotary eccentric reaming tool used in the field of reaming while drilling in the petroleum and natural gas industry.

Background

In the petroleum and gas industry, reaming while drilling is a drilling operation technology which expands the size of an open hole section while drilling so that the size of the open hole section is larger than the inner diameter of an upper casing string. The reaming-while-drilling technology has outstanding advantages in the aspects of reducing the comprehensive drilling cost, improving the quality of the oil and gas well, improving the productivity of the oil and gas well and the like, and has good market prospect.

A reamer is a drill bit that is specifically designed for certain special operations or for relieving accidents. The drill bit is divided into an open-close type reaming bit and a common reaming bit, wherein the former opens the drill bit by using a hydraulic mechanism or by depending on a rotary centrifugal force to cut rocks and enlarge a borehole. The cutting element may be a roller cone bit or a drag bit or a diamond bit. The latter are typically diamond bits with side projections, or bits consisting of fixed blades or rollers having a diameter larger than the pilot bit.

The research on the reamer abroad is early, the research work of reaming while drilling starts in the early 90 s of the 20 th century, the technical level is relatively high, various reaming while drilling reamers such as an eccentric drill bit and a hydraulic reamer have been developed so far, the problems that blades cannot be unlocked and retracted, the reaming size is limited, a water hole is easy to block, the self-cleaning capability is poor and the like generally exist when the reamer is used, and the related reamer products are monopolized abroad, so that the service cost is high. The related research on reaming-while-drilling is carried out later in China, most reaming-while-drilling tools used in the current domestic reaming-while-drilling technology are provided with reaming blades, and the reaming operation is carried out by controlling the reaming blades to be opened by mechanical or hydraulic action force. Based on the defects of the existing reaming tool with the blade type structure while drilling, the eccentric reaming tool has the remarkable advantages of simple structure, low failure rate and low maintenance cost; and after the reaming operation of the eccentric reaming tool is finished, the alignment of the central axis of the eccentric drill bit and the central axis of the drill column is difficult to ensure, so that the eccentric drill bit is clamped at the position of the reducing section at the upper end part of the reaming well section, the drill column is failed to recover in serious conditions, huge economic loss is brought to a construction well team, and the drilling cost is greatly increased.

In view of the problems of high service cost, poor recycling safety of domestic eccentric reaming tools, low reaming efficiency of reaming tools while drilling and the like of the existing foreign reamer, the invention particularly provides a composite rotary eccentric reaming tool.

Disclosure of Invention

The purpose of the invention is: in order to solve the problem that the eccentric drill bit cannot be reliably recovered, improve the efficiency of reaming while drilling and reduce the reaming cost, the composite rotary eccentric reaming tool is provided.

In order to achieve the purpose, the invention adopts the following technical scheme: a composite rotary eccentric reaming tool is composed of an upper joint, a rotor, a thrust bearing, an upper shell, a stator, a universal shaft, a middle shell, a transmission joint, an upper end cover, an O-shaped sealing ring I, a bearing seat, a lip-shaped sealing ring, an upper eccentric ring, a lower shell, an upper mandrel, a bearing II, a lower end cover, a middle joint, a lower mandrel, a limiting cylinder, a mandrel sleeve, a lower joint, a screw, a sealing cover, an eccentric drill bit, a set screw, a piston, a spring, a pressing cap, a transition joint and a lower eccentric ring. The method is characterized in that: the upper end of the upper joint is provided with threads, the lower end of the upper joint is in threaded connection with the upper end of the upper shell, the lower end of the upper shell is in threaded connection with the upper end of the middle shell, the lower end of the middle shell is in threaded connection with the upper end of the lower shell, and the lower end of the lower shell is in threaded connection with the upper end of the middle joint; the lower end of the rotor is in threaded connection with the upper end of the universal shaft, the lower end of the universal shaft is in threaded connection with the upper end of the transmission joint, the lower end of the transmission joint is in threaded connection with the upper end of the upper mandrel, the lower end of the upper mandrel is in threaded connection with the upper end of the lower mandrel, and the lower end of the lower mandrel is in threaded connection with the upper end of the eccentric drill bit.

The middle part of the inner cavity of the upper joint is provided with a stepped hole, the upper end of the rotor is inserted into the stepped hole of the inner cavity of the upper joint, the upper part of the rotor is provided with a circular supporting table, the upper end surface of the supporting table is provided with a thrust bearing, the upper part of the thrust bearing is contacted with the bottom surface of the step of the stepped hole of the inner cavity of the upper joint, the upper part of the rotor is provided with a section of cylindrical cavity, the lower part of the rotor is solid, an overflowing hole I is arranged below the supporting table and is communicated with the inner cavity of the upper part of the rotor and the external annular; the end face of the upper end cover is provided with a through hole, an O-shaped sealing ring I is arranged between the excircle of the upper end cover and the inner wall of the middle shell, the lower end of the upper end cover is in threaded connection with a bearing seat, the through hole is formed in the bearing seat, a bearing I is arranged between the bearing seat and the lower shell, the upper end face of the bearing I is contacted with the bottom of the upper end cover, and the lower end face of the bearing I is contacted with a step surface at; the transition joint is arranged in the inner cavity of the lower shell, the upper end of the transition joint is in threaded connection with the lower end of the bearing seat, the upper part of the inner cavity of the transition joint is provided with a shoulder, the upper eccentric ring is arranged on the upper part of the inner cavity of the transition joint, the lower eccentric ring is arranged on the lower part of the inner cavity of the transition joint, the bottom of the upper eccentric ring is in contact with the shoulder on the upper part of the inner cavity of the transition joint, the inner part of, one of the bearings II is arranged in the eccentric hole of the upper eccentric ring, the other bearing II is sleeved in the middle of the transmission joint, the middle of the transmission joint is provided with a shoulder, the bottom of one of the bearings II is in contact with a shoulder in the middle of the transmission joint, the upper end of the transmission joint is solid, a central channel is arranged in the transmission joint, a through hole is formed in the upper part of the transmission joint and is communicated with the central channel and the outer cavity of the transmission joint, and a lip-shaped sealing ring is arranged between the upper part of the upper eccentric ring and the transmission joint; a shoulder is arranged at the lower part of the inner cavity of the transition joint, the upper end surface of the lower eccentric ring is in contact with the shoulder at the lower part of the inner cavity of the transition joint, a stepped eccentric hole is arranged in the lower eccentric ring, another bearing II is arranged in the eccentric hole of the lower eccentric ring, another bearing II is sleeved in the middle of the upper mandrel, a lip-shaped sealing ring is arranged between the lower part of the lower eccentric ring and the upper mandrel, and the axes of the eccentric hole in the upper eccentric ring and the eccentric hole in the lower eccentric ring are aligned; the upper mandrel is provided with a central through hole, the upper part of the lower end cover is in threaded connection with the lower end of the transition joint, a through hole is formed in the lower end cover, the top of the lower end cover is in contact with the bottom of the lower eccentric ring, an O-shaped sealing ring I is arranged between the outer cylindrical surface of the lower end cover and the lower shell, and the upper mandrel penetrates through the through hole in the lower end cover.

The middle joint is characterized in that an eccentric step hole is formed in the inner cavity of the middle joint, two threaded holes are formed in the middle of the outer circle of the middle joint and communicated with the lower portion of the eccentric step hole, a piston cavity is formed in the upper portion of the inner cavity of the middle joint, a through hole is formed in the bottom of the piston cavity and the step surface of the middle of the eccentric step hole and communicated with each other, a liquid conveying hole is formed in the upper portion of the inner cavity of the middle joint and communicated with the upper end face of the inner; the middle part of the excircle of the lower mandrel is provided with an outer hexagon, and the upper part of the lower mandrel is provided with a overflowing hole II communicated with the inner cavity space and the outer cavity space; the inner cavity of the mandrel sleeve is arranged into an inner hexagon, and the upper part of the excircle of the mandrel sleeve is provided with a semicircular limiting groove II; a semicircular limiting groove I is formed in the upper part of the inner cavity of the limiting cylinder; the hexagonal inner cavity of the mandrel sleeve is sleeved on the hexagonal outer middle part of the outer circle of the lower mandrel, the limiting sleeve is sleeved in the inner cavity of the mandrel sleeve, and the central axes of the limiting groove II at the upper part of the outer circle of the mandrel sleeve and the limiting groove I at the upper part of the inner cavity of the limiting sleeve are superposed to form a circular empty groove; the lower mandrel is placed in an eccentric stepped hole of the middle joint, and the limiting cylinder and the mandrel sleeve are placed at the lower part of the eccentric stepped hole of the middle joint; the piston is arranged in a piston cavity at the upper part of the inner cavity of the middle joint, and a stepped shaft at the lower part of the piston is inserted into a through hole communicated with the bottom of the piston cavity and the stepped surface at the middle part of the eccentric stepped hole; the spring is arranged in a piston cavity at the upper part of the inner cavity of the middle joint and tightly presses the upper end surface of the piston; the upper end hole of the piston cavity at the upper part of the inner cavity of the middle joint is in threaded connection with the pressing cap; a limiting groove I at the upper part of the inner cavity of the limiting cylinder is aligned with the step shaft at the lower end of the piston, two set screws are arranged in two threaded holes in the middle of the outer circle of the middle joint, and the set screws tightly push the limiting cylinder; the lower end of the lower joint is in threaded connection with the lower end of the middle joint; the sealing cover is provided with an eccentric hole, the sealing cover is connected with the lower joint through a screw, and the lower mandrel penetrates through the eccentric hole of the sealing cover.

The center line of a lower body of an eccentric drill bit before going down a well is aligned with the center line of a middle joint body, the upper end of an upper joint is connected with an upper drill column and is sent into the well, when reaming operation is carried out, a well head square rotary table is started to rotate the drill column to drive the whole reaming tool to revolve along with the drill column, then a pump is started to drill the well and a small-displacement circulating drilling fluid is circulated, the drilling fluid enters a fluid transfer hole in the upper part of an inner cavity of the middle joint from an overflow hole II in the upper part of a lower mandrel to be suppressed, the high-pressure drilling fluid pushes a piston to move upwards axially by hydraulic pressure and is separated from a circular empty groove; at the moment, the drilling fluid is circulated in a large discharge amount, the high-pressure drilling fluid drives the rotor to rotate at a high speed, the lower mandrel rotates under the action of the rotor to drive the eccentric bit to rotate, the rotary table on the wellhead side drives the drill string to rotate so as to drive the whole reaming tool system to revolve along with the drill string, namely, the eccentric bit performs reaming operation while drilling under the combined motion of revolution and rotation; after reaming while drilling is finished, the flow of drilling fluid is reduced, the invention is lifted, the pressure of the drilling fluid on the bottom of the piston is reduced, and the piston moves downwards in the axial direction and props against the upper end surfaces of the limiting cylinder and the mandrel sleeve; when the limiting groove II on the upper part of the excircle of the mandrel sleeve rotates to the limiting groove I on the upper part of the inner cavity of the limiting cylinder, and the mandrel is superposed, the stepped shaft on the lower part of the piston is inserted into a circular empty groove formed by the limiting groove II on the excircle of the mandrel sleeve and the limiting groove I on the upper part of the inner cavity of the limiting cylinder, the mandrel sleeve stops rotating, then the lower mandrel and the eccentric drill bit stop rotating, the central axis of the eccentric drill bit is aligned with the central axis of the connector, the pump is stopped at the moment, the drill string is continuously lifted, and the whole eccentric.

The stepped shaft at the lower part of the piston is inserted into a circular empty groove formed by a limiting groove II on the excircle of the mandrel sleeve and a limiting groove I at the upper part of the inner cavity of the limiting cylinder; the rotation angles of the eccentric drill bit and the lower mandrel are adjusted by using a gasket.

And an O-shaped sealing ring is arranged in the lip groove of the lip-shaped sealing ring.

Two to four overflowing holes I are formed below the rotor supporting platform; two to four through holes are arranged at the upper part of the transmission joint; one to two overflowing holes II are formed in the cylindrical surface of the middle upper part of the lower mandrel.

The invention has the beneficial effects that: (1) the eccentric reaming operation is carried out while drilling by combining the eccentric drill bit, the lower eccentric drill bit is driven to revolve by utilizing a well mouth turntable machine, and then the lower eccentric shaft is driven to drive the eccentric drill bit to rotate by combining hydraulic power, so that the compound rotary motion of revolution and rotation of the eccentric drill bit is realized, the reaming efficiency is higher, and a borehole with a larger diameter can be drilled below a borehole with a smaller diameter; (2) after reaming while drilling operation is finished, the eccentric drill bit is convenient and reliable to recover, the problem that the center line of the eccentric drill bit is difficult to align is solved, and economic loss caused by recovery failure of the eccentric drill bit is effectively solved; (3) the eccentric bit is used for reaming while drilling, and compared with a reaming cutter wing type reaming tool, the drilling tool has low failure rate and is beneficial to reducing the drilling cost; (4) the invention has reliable design of all links and can adapt to complex underground working conditions.

Drawings

FIG. 1 is a schematic structural view of a compound rotary eccentric reaming tool of the present invention in a reaming operation state.

Fig. 2 is a schematic view showing the construction of the present invention in a retracted state of the eccentric bit.

Fig. 3 is a sectional view taken along line a-a of fig. 1.

Fig. 4 is a sectional view taken along line B-B of fig. 1.

Fig. 5 is a sectional view of the C-C of fig. 1.

Fig. 6 is a cross-sectional view taken along line D-D of fig. 2.

Fig. 7 is a three-dimensional structural view of the rotor.

In the figure: 1-upper joint, 2-rotor, 3-thrust bearing, 4-upper shell, 5-stator, 6-universal shaft, 7-middle shell, 8-transmission joint, 9-upper end cover, 10-O type sealing ring I, 11-bearing I, 12-bearing seat, 13-lip sealing ring, 14-upper eccentric ring, 15-lower shell, 16-upper mandrel, 17-bearing II, 18-lower end cover, 19-middle joint, 20-lower mandrel, 21-limiting cylinder, 22-mandrel sleeve, 23-lower joint, 24-screw, 25-sealing cover, 26-eccentric bit, 27-set screw, 28-piston, 29-spring, 30-gland, 31-transition joint, 32-lower eccentric ring, 2a 1-overflowing hole I, 2a 2-spiral wing, 191-liquid transmission hole, 201-overflowing hole II, 211-limiting groove I, 221-limiting groove II.

Detailed Description

As shown in fig. 1, 2, 3, 4, 5, 6 and 7, the composite rotary eccentric reaming tool of the present invention is composed of an upper joint 1, a rotor 2, a thrust bearing 3, an upper housing 4, a stator 5, a universal shaft 6, a middle housing 7, a transmission joint 8, an upper end cover 9, an O-ring seal i 10, a bearing i 11, a bearing seat 12, a lip seal 13, an upper eccentric ring 14, a lower housing 15, an upper mandrel 16, a bearing ii 17, a lower end cover 18, a middle joint 19, a lower mandrel 20, a limiting cylinder 21, a mandrel sleeve 22, a lower joint 23, a screw 24, a seal cover 25, an eccentric bit 26, a set screw 27, a piston 28, a spring 29, a press cap 30, a transition joint 31 and a lower eccentric ring 32. The method is characterized in that: the upper end of the upper joint 1 is provided with threads, the lower end of the upper joint 1 is in threaded connection with the upper end of the upper shell 4, the lower end of the upper shell 4 is in threaded connection with the upper end of the middle shell 7, the lower end of the middle shell 7 is in threaded connection with the upper end of the lower shell 15, and the lower end of the lower shell 15 is in threaded connection with the upper end of the middle joint 19; the lower end of the rotor 2 is in threaded connection with the upper end of the universal shaft 6, the lower end of the universal shaft 6 is in threaded connection with the upper end of the transmission joint 8, the lower end of the transmission joint 8 is in threaded connection with the upper end of the upper mandrel 16, the lower end of the upper mandrel 16 is in threaded connection with the upper end of the lower mandrel 20, and the lower end of the lower mandrel 20 is in threaded connection with the upper end of the eccentric drill bit 26.

After the tool is connected, the central lines of the upper joint 1, the upper shell 4, the middle shell 7, the lower shell 15 and the middle joint 19 are positioned on a straight line, the central lines of the transmission joint 8, the upper mandrel 16 and the lower mandrel 20 are positioned on a straight line, and eccentricity exists between the central lines of the upper joint 1, the upper shell 4, the middle shell 7, the lower shell 15 and the middle joint 19 and the central lines of the transmission joint 8, the upper mandrel 16 and the lower mandrel 20, as shown in fig. 2, 4 and 6.

A stepped hole is formed in the middle of an inner cavity of the upper joint 1, the upper end of the rotor 2 is inserted into the stepped hole in the inner cavity of the upper joint 1, a circular support table is arranged on the upper portion of the rotor 2, a thrust bearing 3 is arranged on the upper end face of the support table, the upper portion of the thrust bearing 3 is in contact with the bottom surface of a step of the stepped hole in the inner cavity of the upper joint 1, a section of cylindrical cavity is arranged on the upper portion of the rotor 2, the lower portion of the rotor 2 is solid, two to four overflowing holes I2 a1 are formed below the support table and are communicated with the inner cavity in the upper portion of the rotor 2 and an external annular space, two overflowing holes I; the outer side of the spiral wing 2a2 contacts with the inner surface of the stator 5, and the outer cylindrical surface of the stator 5 is bonded with the inner surface of the upper shell 4. The end face of the upper end cover 9 is provided with a through hole, an O-shaped sealing ring I10 is arranged between the outer circle of the upper end cover 9 and the inner wall of the middle shell 7, the lower end of the upper end cover 9 is in threaded connection with the bearing seat 12, the through hole is formed in the bearing seat 12, the bearing I11 is arranged between the bearing seat 12 and the lower shell 15, the upper end face of the bearing I11 is in contact with the bottom of the upper end cover 9, and the lower end face of the bearing I11 is in contact with the. The transition joint 31 is arranged in the inner cavity of the lower shell 15, the upper end of the transition joint 31 is in threaded connection with the lower end of the bearing seat 12, the upper part of the inner cavity of the transition joint 31 is provided with a shoulder, the upper eccentric ring 14 is arranged on the upper part of the inner cavity of the transition joint 31, the lower eccentric ring 32 is arranged on the lower part of the inner cavity of the transition joint 31, the bottom of the upper eccentric ring 14 is in contact with the shoulder on the upper part of the inner cavity of the transition joint 31, the inner part of the upper eccentric ring 14 is provided with two stepped eccentric holes, one bearing II 17 is arranged in the eccentric hole of the upper eccentric ring 14, one bearing II 17 is sleeved in the middle of the transmission joint 8, the middle part of the transmission joint 8 is provided with a shoulder, the bottom of one bearing II 17 is in contact with the shoulder in the middle of the transmission joint 8, the upper, in this embodiment, two through holes are formed in the upper portion of the driving joint 8, and a lip-shaped sealing ring 13 is disposed between the upper portion of the upper eccentric ring 14 and the driving joint 8.

A shoulder is arranged at the lower part of the inner cavity of the transition joint 31, the upper end surface of the lower eccentric ring 32 is contacted with the shoulder at the lower part of the inner cavity of the transition joint 31, a stepped eccentric hole is arranged in the lower eccentric ring 32, another bearing II 17 is arranged in the eccentric hole of the lower eccentric ring 32, another bearing II 17 is sleeved at the middle part of the upper mandrel 16, a lip-shaped sealing ring 13 is arranged between the lower part of the lower eccentric ring 32 and the upper mandrel 16, and the axes of the eccentric hole in the upper eccentric ring 14 and the eccentric hole in the lower eccentric ring 32 are aligned; the upper mandrel 16 is provided with a central through hole, the upper part of the lower end cover 18 is in threaded connection with the lower end of the transition joint 31, the through hole is formed in the lower end cover 18, the top of the lower end cover 18 is in contact with the bottom of the lower eccentric ring 32, an O-shaped sealing ring I10 is arranged between the outer cylindrical surface of the lower end cover 18 and the lower shell 15, and the upper mandrel 16 penetrates through the through hole in the lower end cover 18. An O-shaped sealing ring is arranged in a lip groove of the lip-shaped sealing ring 13.

An eccentric stepped hole is formed in the inner cavity of the middle joint 19, two threaded holes are formed in the middle of the outer circle of the middle joint 19 and communicated with the lower portion of the eccentric stepped hole, a piston cavity is formed in the upper portion of the inner cavity of the middle joint 19, the bottom of the piston cavity is communicated with a through hole formed in the middle of the eccentric stepped hole, as shown in fig. 1 and 3, a liquid conveying hole 191 is formed in the upper portion of the inner cavity of the middle joint 19 and communicated with the upper end face of the inner cavity of the middle joint 19 and the lower portion of the piston cavity; the middle part of the excircle of the lower mandrel 20 is provided with an outer hexagon, the upper part of the lower mandrel 20 is provided with one to two overflowing holes II 201 which are communicated with the inner cavity space and the outer cavity space, and the overflowing holes II 201 are arranged in the embodiment; the inner cavity of the mandrel sleeve 22 is arranged as an inner hexagon, and the upper part of the excircle of the mandrel sleeve 22 is provided with a semicircular limiting groove II 221; the upper part of the inner cavity of the limiting cylinder 21 is provided with a semicircular limiting groove I211 as shown in figure 4. The hexagonal cover in the mandrel sleeve 22 inner chamber is on the outer hexagonal of mandrel 20 excircle middle part, and spacing section of thick bamboo 21 cover is in mandrel sleeve 22 inner chamber, and spacing groove II 221 on mandrel sleeve 22 excircle upper portion and spacing groove I211 on spacing section of thick bamboo 21 inner chamber upper portion central axis coincide can form circular dead slot. The lower mandrel 20 is placed in an eccentric stepped hole of the middle joint 19, and the limiting cylinder 21 and the mandrel sleeve 22 are placed at the lower part of the eccentric stepped hole of the middle joint 19; the piston 28 is arranged in a piston cavity at the upper part of the inner cavity of the middle joint 19, and a step shaft at the lower part of the piston 28 is inserted into a through hole communicated with the bottom of the piston cavity and the step surface at the middle part of the eccentric step hole. The spring 29 is placed in the piston cavity at the upper part of the inner cavity of the middle joint 19, and the spring 29 presses the upper end surface of the piston 28. The pressing cap 30 is in threaded connection with the upper end opening of the piston cavity at the upper part of the inner cavity of the middle joint 19. The limiting groove I211 at the upper part of the inner cavity of the limiting cylinder 21 is aligned with the step shaft at the lower end of the piston 28, two set screws 27 are arranged in two threaded holes in the middle of the outer circle of the middle joint 19, and the set screws 27 tightly push the limiting cylinder 21, as shown in fig. 5. The lower end of the lower joint 23 is connected with the lower end of the middle joint 19 through screw threads; the sealing cover 25 is provided with an eccentric hole, the sealing cover 25 and the lower joint 23 are connected by a screw 24, and the lower mandrel 20 passes through the eccentric hole of the sealing cover 25.

The center line of the threaded connection section at the upper part of the eccentric drill bit 26 and the center line of the body at the lower part of the eccentric drill bit 26 are provided with eccentricity.

As shown in fig. 2, before going downhole, the rotation angle between the eccentric bit 26 and the lower mandrel 20 is adjusted by a gasket, so that the center line of the lower body of the eccentric bit 26 is aligned with the center line of the body of the middle joint 19, and the stepped shaft at the lower part of the piston 28 before going downhole is inserted into the circular hollow groove formed by the limiting groove ii 221 on the outer circle of the mandrel sleeve 22 and the limiting groove i 211 on the upper part of the inner cavity of the limiting cylinder 21, as shown in fig. 6, so that the mandrel sleeve 22 cannot rotate, and the lower mandrel 20 and the eccentric bit 26 are prevented from rotating; the invention is connected with an upper drill column through the upper end of an upper connector 1 and is sent into a well; when the reaming operation is carried out, the well head square rotary table is started to rotate the drill string to drive the whole reaming tool to revolve along with the drill string, then a pump is started to drill a well and small-displacement circulating drilling fluid enters the fluid transfer hole 191 in the upper part of the inner cavity of the middle joint 19 from the overflow hole II 201 in the upper part of the lower mandrel 20 to be suppressed, the high-pressure drilling fluid pushes the piston 28 to move upwards axially by hydraulic pressure and is separated from a circular empty groove formed by the limiting groove II 221 in the outer circle of the mandrel sleeve 22 and the limiting groove I211 in the upper part of the inner cavity of the limiting cylinder 21, and the circular. At the moment, the high-discharge-rate circulating drilling fluid drives the rotor 2 to rotate at a high speed, the lower mandrel 20 rotates under the action of the rotor 2 to drive the eccentric bit 26 to rotate, the rotary table on the wellhead side drives the drill string to rotate so as to drive the whole reaming tool system to revolve along with the drill string, namely, the eccentric bit 26 performs reaming operation while drilling under the combined rotation of revolution and rotation, so that the efficiency of reaming while drilling is improved, and a borehole with a larger diameter can be drilled under a borehole with a smaller diameter.

After reaming while drilling is completed, the flow of drilling fluid is reduced, the invention is lifted, at the moment, the pressure of the drilling fluid borne by the bottom of the piston 28 is reduced, and the piston 28 moves downwards in the axial direction to prop against the upper end surfaces of the limiting cylinder 21 and the mandrel sleeve 22; when the limiting groove II 221 at the upper part of the excircle of the mandrel sleeve 22 rotates to the central shaft of the limiting groove I211 at the upper part of the inner cavity of the limiting cylinder 21, the step shaft at the lower part of the piston 28 is inserted into a circular hollow groove formed by the limiting groove II 221 at the excircle of the mandrel sleeve 22 and the limiting groove I211 at the upper part of the inner cavity of the limiting cylinder 21, the mandrel sleeve 22 stops rotating, the lower mandrel 20 and the eccentric drill bit 26 stop rotating, the central axis of the eccentric drill bit 26 is aligned with the central axis of the joint 19, the pump is stopped at the moment, the drill string is continuously lifted, and the whole eccentric reaming tool is completely. The steps realize the advantages of convenient and reliable recovery of the eccentric drill bit after the reaming operation is finished, overcome the problem of difficult alignment of the central line of the eccentric drill bit and effectively solve the economic loss caused by the recovery failure of the eccentric drill bit; meanwhile, each link of the invention is designed reliably and can adapt to complex underground working conditions; the eccentric bit is used for reaming while drilling, the failure rate is low compared with a reaming cutter wing type reaming tool, and the drilling cost is favorably reduced.

Claims

1. A composite rotary eccentric reaming tool is composed of an upper joint (1), a rotor (2), a thrust bearing (3), an upper shell (4), a stator (5), a universal shaft (6), a middle shell (7), a transmission joint (8), an upper end cover (9), an O-shaped sealing ring I (10), a bearing I (11), a bearing seat (12), a lip-shaped sealing ring (13), an upper eccentric ring (14), a lower shell (15), an upper mandrel (16), a bearing II (17), a lower end cover (18), a middle joint (19), a lower mandrel (20), a limiting cylinder (21), a mandrel sleeve (22), a lower joint (23), a screw (24), a sealing cover (25), an eccentric drill bit (26), a set screw (27), a piston (28), a spring (29), a pressing cap (30), a transition joint (31) and a lower eccentric ring (32); the method is characterized in that: the upper end of the upper joint (1) is provided with threads, the lower end of the upper joint (1) is in threaded connection with the upper end of the upper shell (4), the lower end of the upper shell (4) is in threaded connection with the upper end of the middle shell (7), the lower end of the middle shell (7) is in threaded connection with the upper end of the lower shell (15), and the lower end of the lower shell (15) is in threaded connection with the upper end of the middle joint (19); the lower end of the rotor (2) is in threaded connection with the upper end of the universal shaft (6), the lower end of the universal shaft (6) is in threaded connection with the upper end of the transmission joint (8), the lower end of the transmission joint (8) is in threaded connection with the upper end of the upper mandrel (16), the lower end of the upper mandrel (16) is in threaded connection with the upper end of the lower mandrel (20), and the lower end of the lower mandrel (20) is in threaded connection with the upper end of the eccentric drill bit (26);

the middle part of an inner cavity of the upper joint (1) is provided with a stepped hole, the upper end of a rotor (2) is inserted into the stepped hole of the inner cavity of the upper joint (1), the upper part of the rotor (2) is provided with a circular supporting table, the upper end surface of the supporting table is provided with a thrust bearing (3), the upper part of the thrust bearing (3) is contacted with the bottom surface of the step of the stepped hole of the inner cavity of the upper joint (1), the upper part of the rotor (2) is provided with a section of cylindrical cavity, the lower part of the rotor (2) is solid, a through hole I (2 a 1) is arranged below the supporting table and is communicated with the inner cavity of the upper part of the rotor (2) and an external annular space, the middle part of the rotor (2) is provided with a spiral wing (2 a 2), the; the end face of the upper end cover (9) is provided with a through hole, an O-shaped sealing ring I (10) is arranged between the excircle of the upper end cover (9) and the inner wall of the middle shell (7), the lower end of the upper end cover (9) is in threaded connection with a bearing seat (12), the inside of the bearing seat (12) is provided with the through hole, a bearing I (11) is arranged between the bearing seat (12) and the lower shell (15), the upper end face of the bearing I (11) is in contact with the bottom of the upper end cover (9), and the lower end face of the bearing I (11) is in contact with a step surface; the transition joint (31) is arranged in the inner cavity of the lower shell (15), the upper end of the transition joint (31) is in threaded connection with the lower end of the bearing seat (12), the upper part of the inner cavity of the transition joint (31) is provided with a shoulder, the upper eccentric ring (14) is arranged on the upper part of the inner cavity of the transition joint (31), the lower eccentric ring (32) is arranged on the lower part of the inner cavity of the transition joint (31), the bottom of the upper eccentric ring (14) is in contact with the shoulder on the upper part of the inner cavity of the transition joint (31), the inner part of the upper eccentric ring (14) is provided with two stepped eccentric holes, the bearings II (17) are provided, one bearing II (17) is arranged in the eccentric hole of the upper eccentric ring (14), one bearing II (17) is sleeved in the middle part of the transmission joint (8), the middle part of the transmission joint (8) is provided with a shoulder, the bottom, a central channel is arranged in the transmission joint (8), a through hole is arranged at the upper part of the transmission joint (8) to communicate the central channel and the outer cavity of the transmission joint (8), and a lip-shaped sealing ring (13) is arranged between the upper part of the upper eccentric ring (14) and the transmission joint (8); a shoulder is arranged at the lower part of the inner cavity of the transition joint (31), the upper end surface of the lower eccentric ring (32) is contacted with the shoulder at the lower part of the inner cavity of the transition joint (31), a stepped eccentric hole is arranged in the lower eccentric ring (32), another bearing II (17) is arranged in the eccentric hole of the lower eccentric ring (32), the other bearing II (17) is sleeved at the middle part of the upper mandrel (16), a lip-shaped sealing ring (13) is arranged between the lower part of the lower eccentric ring (32) and the upper mandrel (16), and the axes of the eccentric hole in the upper eccentric ring (14) and the eccentric hole in the lower eccentric ring (32) are aligned; the upper mandrel (16) is provided with a central through hole, the upper part of the lower end cover (18) is in threaded connection with the lower end of the transition joint (31), the lower end cover (18) is internally provided with the through hole, the top of the lower end cover (18) is in contact with the bottom of the lower eccentric ring (32), an O-shaped sealing ring I (10) is arranged between the outer cylindrical surface of the lower end cover (18) and the lower shell (15), and the upper mandrel (16) penetrates through the through hole in the lower end cover (18);

an eccentric stepped hole is formed in the inner cavity of the middle joint (19), two threaded holes are formed in the middle of the outer circle of the middle joint (19) and communicated with the lower portion of the eccentric stepped hole, a piston cavity is formed in the upper portion of the inner cavity of the middle joint (19), a through hole is formed in the bottom of the piston cavity and the stepped surface of the middle of the eccentric stepped hole and communicated with each other, a liquid conveying hole (191) is formed in the upper portion of the inner cavity of the middle joint (19) and communicated with the upper end face of the inner cavity of the middle joint (19) and the lower portion of the piston; the middle part of the excircle of the lower mandrel (20) is provided with an outer hexagon, and the upper part of the lower mandrel (20) is provided with an overflowing hole II (201) communicated with the inner cavity space and the outer cavity space; the inner cavity of the mandrel sleeve (22) is arranged as an inner hexagon, and the upper part of the excircle of the mandrel sleeve (22) is provided with a semicircular limiting groove II (221); the upper part of the inner cavity of the limiting cylinder (21) is provided with a semicircular limiting groove I (211); the inner hexagon of the inner cavity of the mandrel sleeve (22) is sleeved on the outer hexagon of the middle part of the outer circle of the lower mandrel (20), the limiting cylinder (21) is sleeved on the inner cavity of the mandrel sleeve (22), and the central axes of a limiting groove II (221) at the upper part of the outer circle of the mandrel sleeve (22) and a limiting groove I (211) at the upper part of the inner cavity of the limiting cylinder (21) are superposed to form a circular empty groove; the lower mandrel (20) is placed in an eccentric stepped hole of the middle joint (19), and the limiting cylinder (21) and the mandrel sleeve (22) are placed at the lower part of the eccentric stepped hole of the middle joint (19); a piston (28) is arranged in a piston cavity at the upper part of the inner cavity of the middle joint (19), and a step shaft at the lower part of the piston (28) is inserted into a through hole communicated with the bottom of the piston cavity and the step surface at the middle part of the eccentric step hole; the spring (29) is arranged in a piston cavity at the upper part of the inner cavity of the middle joint (19), and the spring (29) compresses the upper end surface of the piston (28); the pressure cap (30) is in threaded connection with the upper end orifice of the piston cavity at the upper part of the inner cavity of the middle joint (19); a limiting groove I (211) at the upper part of the inner cavity of the limiting cylinder (21) is aligned with the step shaft at the lower end of the piston (28), two set screws (27) are arranged in two threaded holes in the middle of the outer circle of the middle joint (19), and the set screws (27) tightly push the limiting cylinder (21); the lower end of the lower joint (23) is in threaded connection with the lower end of the middle joint (19); the sealing cover (25) is provided with an eccentric hole, the sealing cover (25) is connected with the lower connector (23) by a screw (24), and the lower mandrel (20) penetrates through the eccentric hole of the sealing cover (25);

the center line of a lower body of an eccentric drill bit (26) before descending a well is aligned with the center line of a body of a middle joint (19), the upper end of an upper joint (1) is connected with an upper drill string and is sent into the well, when reaming operation is carried out, a well head square rotary table is started to rotate the drill string to drive the whole reaming tool to revolve along with the drill string, then a pump is started to drill the well and small-displacement circulating drilling fluid is circulated, the drilling fluid enters a fluid transfer hole (191) in the upper part of an inner cavity of the middle joint (19) from an overflow hole II (201) in the upper part of a lower mandrel (20) to be suppressed, the high-pressure drilling fluid pushes a piston (28) to move upwards axially by hydraulic pressure and is separated from a circular empty groove formed by a limiting groove II (221) in the excircle; at the moment, the drilling fluid is circulated in a large discharge amount, the high-pressure drilling fluid drives the rotor (2) to rotate at a high speed, the lower mandrel (20) rotates under the action of the rotor (2) to drive the eccentric drill bit (26) to rotate, the rotary table on the wellhead side drives the drill string to rotate so as to drive the whole reaming tool system to revolve along with the drill string, namely, the eccentric drill bit (26) performs reaming operation while drilling under the combined motion of revolution and rotation; after reaming while drilling is finished, the flow of drilling fluid is reduced, the invention is lifted, the pressure of the drilling fluid borne by the bottom of the piston (28) is reduced, and the piston (28) moves downwards in the axial direction to prop against the upper end surfaces of the limiting cylinder (21) and the mandrel sleeve (22); when the limiting groove II (221) at the upper part of the excircle of the mandrel sleeve (22) rotates to the central shaft of the limiting groove I (211) at the upper part of the inner cavity of the limiting cylinder (21), the step shaft at the lower part of the piston (28) is inserted into a circular hollow groove formed by the limiting groove II (221) at the excircle of the mandrel sleeve (22) and the limiting groove I (211) at the upper part of the inner cavity of the limiting cylinder (21), the mandrel sleeve (22) stops rotating, then the lower mandrel (20) and the eccentric drill bit (26) stop rotating, the central axis of the eccentric drill bit (26) is aligned with the central axis of the joint (19), at the moment, the pump is stopped, the drill string is continuously lifted, and the whole eccentric reaming tool is completely.

2. The composite rotary eccentric reaming tool of claim 1, wherein: the stepped shaft at the lower part of the piston (28) is inserted into a circular hollow groove formed by a limiting groove II (221) on the excircle of the mandrel sleeve (22) and a limiting groove I (211) at the upper part of the inner cavity of the limiting cylinder (21); the rotation angles of the eccentric drill bit (26) and the lower mandrel (20) are adjusted by using a gasket.

3. The composite rotary eccentric reaming tool of claim 1, wherein: and an O-shaped sealing ring is arranged in a lip groove of the lip-shaped sealing ring (13).

4. The composite rotary eccentric reaming tool of claim 1, wherein: two to four overflowing holes I (2 a 1) are formed below the supporting platform of the rotor (2); two to four through holes are arranged at the upper part of the transmission joint (8); one to two overflowing holes II (201) are arranged on the cylindrical surface of the middle upper part of the lower mandrel (20).