CN212130398U

CN212130398U - Variable-diameter while-drilling reamer and variable-diameter adjusting structure thereof

Info

Publication number: CN212130398U
Application number: CN202020350318.3U
Authority: CN
Inventors: 刘统亮; 张红; 严淳鳀; 冯定
Original assignee: Yangtze University
Current assignee: Yangtze University
Priority date: 2020-03-18
Filing date: 2020-03-18
Publication date: 2020-12-11
Anticipated expiration: 2030-03-18

Abstract

The utility model discloses a structure is adjusted to reducing is applied to on the reamer along with boring, and this reamer along with boring has the reamer cutting knife, drive reamer cutting knife goes out the driving source of sword, drive reamer cutting knife move back the piece that resets of sword, holding reamer cutting knife and the reamer urceolus that resets, and the piece that resets is coaxial with the reamer urceolus to be arranged, and this structure is adjusted to reducing includes: closed loop composite trough, sliding pin, the one end of sliding pin with closed loop composite trough sliding connection, reamer urceolus and reset one of them and be provided with closed loop composite trough, reamer urceolus and reset another of one of them and be provided with the sliding pin, the utility model also provides a but reducing is along with boring reamer, on this reducing is adjusted the structure and is applied to along with boring reamer, the sliding pin slides in closed loop composite trough, realizes the location of sliding pin in different vertical position, can accomplish two kind at least sizes well when singly creeping into, reduces and plays the drilling number of times, improves drilling efficiency.

Description

Variable-diameter while-drilling reamer and variable-diameter adjusting structure thereof

Technical Field

The utility model relates to an oil gas field is along with boring reaming technical field, concretely relates to variable diameter is along with boring reamer and reducing regulation structure thereof.

Background

With the deepening of the understanding of the mechanism of oil and gas reservoir formation and the deepening of the development of oil and gas fields, the problems encountered in drilling are more and more complex, the solution of the complex problems also depends on the development of tools and the perfection of means, and the reaming-while-drilling technology is proposed and developed based on the background. The reaming-while-drilling technology is a drilling technology which adopts a reaming-while-drilling tool and a conventional drill bit procedure to drill comprehensively and simultaneously enlarge a borehole. The reaming-while-drilling technology has obvious advantages in the aspects of treating underground complex conditions, reducing comprehensive drilling cost, improving drilling speed, improving well construction quality and safety and the like.

However, the reaming while drilling technology currently used has at least the following technical problems:

the reaming aperture of the reaming device is fixed, the times of tripping the reaming device in reaming operation are more, the non-production time is increased, and the operation efficiency is low.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome above-mentioned technique not enough, provide a but variable diameter is along with boring reamer and reducing regulation structure thereof, solve among the prior art reaming operation the many technical problem of the number of times of getting up to bore of reaming device.

In order to achieve the technical purpose, the technical scheme of the utility model provide a structure is adjusted to reducing is applied to on the reamer along with boring, this reamer along with boring has the piece that resets of the driving source of reaming cutting knife, drive reaming cutting knife play sword, drive reaming cutting knife retreat sword, holding reaming cutting knife and the reamer urceolus that resets of reaming cutting knife, resets and arranges with the reamer urceolus is coaxial, and this structure is adjusted to reducing includes:

the closed-loop combined groove comprises a plurality of first sliding grooves and a plurality of second sliding grooves, the first sliding grooves and the second sliding grooves are uniformly distributed along the circumferential direction of a reset piece, the length direction of each first sliding groove and each second sliding groove is consistent with the axial direction of the reset piece, the first sliding grooves are arranged below the second sliding grooves, the upper ends of the first sliding grooves are provided with first guide grooves formed by inclining/bending towards one side of one adjacent second sliding groove, the first guide grooves are communicated with the side walls of the lower parts of the second sliding grooves, the lower ends of the second sliding grooves are provided with second guide grooves formed by inclining/bending towards one side of the other adjacent first sliding groove, and the lower ends of the second guide grooves are communicated with the side walls of the upper parts of the other first sliding grooves, at least two first sliding grooves are different in length;

one end of the sliding pin is in sliding connection with the closed-loop combination groove;

wherein, one of reamer urceolus and the piece that resets is provided with closed loop composite groove, and another one of reamer urceolus and the piece that resets is provided with the sliding pin.

The utility model also provides a but reducing reamer while drilling, include:

the outer reamer barrel is provided with a plurality of cutter discharging grooves penetrating through the inner peripheral surface of the outer reamer barrel, and first guide inclined planes inclined to the axis of the outer reamer barrel are arranged in the cutter discharging grooves;

the reaming cutters are arranged in the cutter grooves and are in one-to-one correspondence sliding connection with the cutter grooves, and second guide inclined planes matched with the first guide inclined planes are arranged on the reaming cutters;

the core tube is arranged in the outer barrel of the reamer, the lower part of the core tube is provided with a first flow guide opening penetrating through the inner peripheral surface of the core tube, liquid sprayed out of the first flow guide opening is used as a driving source, and the liquid sprayed out of the first flow guide opening can generate a first driving force for driving the reaming cutter to slide out to the outer side of the cutter outlet groove;

the reset piece is sleeved on the core pipe in a sliding mode, is coaxially and rotatably connected with the core pipe, and abuts against one end, far away from the first flow guide opening, of the reaming cutter;

the reducing adjusting structure is as described above;

the first elastic piece is abutted to one end of the resetting piece, so that the resetting piece generates a second driving force for the reaming cutter, and the direction of the second driving force is opposite to that of the first driving force.

Compared with the prior art, the beneficial effects of the utility model include: the reducing adjusting structure is applied to a drilling reamer, a sliding pin slides in a closed loop combined groove to realize the positioning of the sliding pin at different vertical positions, liquid sprayed out of a first flow guide opening can drive the outer side of a reaming cutter to slide out of a cutter outlet groove, the reaming cutter slides out from the obliquely upper side under the guiding action of a first guide inclined surface and a second guide line surface, at the moment, the reaming cutter jacks up a reset piece abutted against the reaming cutter, at the moment, the sliding pin slides downwards relative to the closed loop combined groove, finally, the sliding pin stops sliding after sliding to the lower end of a first sliding groove, and when the pressure of water flow sprayed out of the first flow guide opening is reduced, so that when the first driving force is smaller than the second driving force, the reset piece slides downwards relative to an outer barrel of the reamer to enable the sliding pin to slide upwards relative to the closed loop combined groove, the sliding pin slides into the second sliding groove adjacent to the first guiding groove along the inclination direction of the first guiding groove, finally, the sliding pin stops sliding after sliding into the upper end of the second sliding groove, at the moment, the water flow pressure sprayed from the first flow guide port is increased, so that the first driving force is greater than the second driving force, the sliding pin slides downwards again, the sliding pin slides into the second guiding groove from the lower end of the second sliding groove, the sliding pin slides into the first guiding groove adjacent to the second guiding groove along the inclination direction of the second guiding groove, so that the sliding pin slides in different first sliding grooves, when the lengths of the first sliding grooves into which the sliding pin slides are different, the upward sliding distances of the reset piece relative to the outer cylinder of the reamer are also different, so that the limitation on the sliding distance of the reaming cutter from the cutter groove is realized, and the adjustment of the cutter outer diameter of the reaming cutter is realized, the drilling machine can finish at least two sizes of well bores in single drilling, reduce the drilling times and improve the drilling efficiency.

Drawings

FIG. 1 is a schematic external perspective view of an embodiment of a variable-diameter reamer as provided by the present invention;

FIG. 2 is a schematic diagram illustrating an internal structure of an upper portion of an embodiment of a variable diameter reamer of the present invention;

FIG. 3 is a schematic diagram of a first perspective internal structure of a lower half of an embodiment of a variable diameter reamer of the present invention;

FIG. 4 is a schematic diagram illustrating a second perspective internal structure of a lower half of an embodiment of a variable diameter reamer of the present invention;

fig. 5 is a schematic perspective view of the reset member body of the present invention;

FIG. 6 is a schematic perspective view of a core tube according to the present invention;

fig. 7 is a schematic view of the three-dimensional structure of the reaming cutter of the utility model;

FIG. 8 is a schematic perspective view of the outer cylinder of the reamer of the present invention;

fig. 9 is a schematic view of the connection structure between the middle limit piston and the ring groove of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, 2, 3, and 4, the present embodiment provides a reducing adjustment structure applied to a reamer while drilling, the reamer while drilling includes a reamer 1, a driving source (pressure of drilling fluid) for driving the reamer 1 to exit, a reset member 2 for driving the reamer 1 to retract, and a reamer outer cylinder 3 for accommodating the reamer 1 and the reset member 2, the reset member 2 is disposed coaxially with the reamer outer cylinder 3, and the reducing adjustment structure includes:

referring to fig. 5, the closed-loop combination slot includes a plurality of first sliding grooves 2a and a plurality of second sliding grooves 2b, the first sliding grooves 2a and the second sliding grooves 2b are all uniformly arranged along a circumferential direction of the reset member 2, a length direction of each of the first sliding grooves 2a and the second sliding grooves 2b is consistent with an axial direction of the reset member 2, the first sliding groove 2a is disposed below the second sliding groove 2b, an upper end of the first sliding groove 2a is provided with a first guide groove 2c formed by inclining/bending toward one side of one of the second sliding grooves 2b adjacent thereto, the first guide groove 2c is communicated with a side wall of a lower portion of the second sliding groove 2b, a lower end of the second sliding groove 2b is provided with a second guide groove 2d formed by inclining/bending toward one side of the other first sliding groove 2a adjacent thereto, the lower end of the second guide groove 2d is communicated with the side wall of the upper part of the other first sliding groove 2a, and at least two first sliding grooves 2a have different lengths.

And one end of the sliding pin is in sliding connection with the closed-loop combination groove.

One of the outer cylinder 3 and the reset part 2 of the reamer is provided with the closed-loop combination groove, and the other one of the outer cylinder 3 and the reset part 2 of the reamer is provided with the sliding pin (not shown in the figure, and the mounting hole 4 for mounting the sliding pin is shown in the figure), that is, the sliding track of the sliding pin in the closed-loop combination groove is the relative movement track of the outer cylinder 3 and the reset part 2 of the reamer, in this embodiment, the closed-loop combination groove is arranged on the outer circumferential surface of the reset part 2, one end of the sliding pin is fixedly connected with the outer cylinder 3 of the reamer, and the other end of the sliding pin is arranged in the closed-loop combination groove in a sliding manner.

The embodiment further provides a specific implementation manner, and the lengths of the first sliding grooves 2a are sequentially increased/shortened along the circumferential direction of the reset piece 2, so that multi-stage sequential diameter changing is realized.

The present embodiment further provides a variable diameter reamer while drilling, including:

referring to fig. 7 and 8, the outer cylinder 3 of the reamer is provided with a plurality of cutter discharging grooves penetrating through the inner and outer peripheral surfaces of the outer cylinder 3 of the reamer, and the cutter discharging grooves are internally provided with first guiding inclined surfaces a3 arranged obliquely to the axis of the outer cylinder of the reamer;

the reaming cutter 1 is provided with a plurality of reaming cutters 1, the reaming cutters 1 are in one-to-one sliding connection with the cutter outlet grooves, second guide inclined planes a1 matched with the first guide inclined planes are arranged on the reaming cutters 1, and the reaming cutters 1 slide out of the cutter outlet grooves and synchronously rotate along with the reamer outer barrel 3, so that reaming action can be realized.

The core tube 5 is arranged in the outer barrel 3 of the reamer, a first flow guide opening 5a penetrating through the inner peripheral surface of the core tube 5 is formed in the lower portion of the core tube 5, liquid sprayed out of the first flow guide opening 5a serves as a driving source, and the liquid sprayed out of the first flow guide opening 5a can generate a first driving force for driving the reaming cutter 1 to slide out of the cutter outlet groove.

Reset 2, reset 2 slip cap locate core pipe 5, and reset 2 with the coaxial rotation of core pipe 5 is connected, reset 2 butt in reaming cutting knife 1 is kept away from the one end of first water conservancy diversion 5a mouth, in this embodiment, reset 2 is the cylinder, closed loop combination groove set up with reset 2's outer peripheral face.

The reducing adjustment structure of any one of the above items.

The first elastic member 6, the first elastic member 6 abuts against one end of the reset member 2, so that the reset member 2 generates a second driving force to the reaming cutter 1, and the direction of the second driving force is opposite to the direction of the first driving force.

The liquid sprayed out from the first guiding opening 5a can drive the outside of the reaming cutter 1 to slide out of the cutter outlet groove, and under the guiding action of the first guiding inclined plane and the second guiding line plane, the reaming cutter 1 slides out from the oblique upper direction, at this time, the reaming cutter 1 jacks up the resetting piece 2 abutted against the reaming cutter 1, at this time, the sliding pin slides downwards relative to the closed loop combination groove, finally, the sliding pin stops sliding after sliding to the lower end of the first sliding groove 2a, when the pressure of the water flow sprayed out from the first guiding opening 5a is reduced, so that the first driving force is smaller than the second driving force, the resetting piece 2 slides downwards relative to the reamer outer cylinder 3, so that the sliding pin slides upwards relative to the closed loop combination groove, and the sliding pin slides into the second sliding groove 2b adjacent to the first guiding groove 2c along the inclination direction of the first guiding groove, finally, the sliding pin stops sliding after sliding into the upper end of the second sliding groove 2b, at the moment, the water pressure of the first flow guide port 5a is increased, so that the first driving force is greater than the second driving force, the sliding pin slides downwards again, the sliding pin slides into the second guide groove 2d from the lower end of the second sliding groove 2b, the sliding pin slides into the first guide groove 2c adjacent to the second guide groove 2d along the inclined direction of the second guide groove 2d, so that the sliding pin slides in different first sliding grooves 2a, when the lengths of the first sliding grooves 2a into which the sliding pin slides are different, the upward sliding distances of the reset piece 2 relative to the reamer outer cylinder 3 are also different, so that the limitation on the sliding distance of the reaming cutter 1 from the cutter groove is realized, the adjustment on the cutter outer diameter of the reaming cutter 1 is realized, and at least two sizes of boreholes can be completed during single drilling, the drilling tripping times are reduced, and the drilling efficiency is improved.

In this embodiment, the variable diameter reamer while drilling further includes a first safety pin 7, one end of the first safety pin 7 is connected to the reamer outer cylinder 3, the other end of the first safety pin 7 is connected to the reset piece 2, the reset piece 2 includes a reset piece body 21 and a cutter rest 22 arranged between the reset piece body 21 and the reamer cutter 1, the closed-loop combination groove is arranged on the outer circumferential surface of the reset piece body 21, one end of the first safety pin 7 is inserted into a first insertion hole arranged on the inner circumferential surface of the reamer outer cylinder 3, and the other end of the first safety pin 7 is inserted into a second insertion hole arranged on the outer circumferential surface of the cutter rest 22.

In the process of descending the variable-diameter drill reamer into the well, the first safety pin 7 limits the reaming cutter 1 to slide relative to the cutter outlet groove, so that the reaming cutter 1 is locked, namely the reaming cutter 1 does not damage the reamer outer barrel 3 in the process of descending the well, when the reaming cutter 1 starts to cut, drilling fluid is sprayed out from the first flow guide opening 5a to generate a first driving force for driving the reaming cutter 1 to slide out of the cutter outlet groove, meanwhile, the reaming cutter 1 jacks up the cutter frame 22 and cuts off the first safety pin 7, and the first safety pin 7 only plays a safety protection role in the process of descending the well.

Referring to fig. 9, the inner circumferential surface of the reamer outer cylinder 3 is provided with a plurality of annular clamping grooves 3a, the plurality of annular clamping grooves 3a are sequentially arranged along the axial direction of the reamer outer cylinder 3, the annular clamping grooves 3a are located below the cutter outlet grooves, the annular clamping grooves 3a are located above the first flow guide port 5a, the upper side surfaces of the annular clamping grooves 3a are gradually inclined upwards from inside to outside, the lower side surfaces of the annular clamping grooves 3a are perpendicular to the axial line of the core tube 5, a cylindrical gap is provided between the reamer outer cylinder 3 and the core tube 5, the reaming assembly further comprises a core tube cap 8 and an active piston 9, the core tube cap 8 is arranged below the first flow guide port 5a, the core tube cap 8 is sealed at the lower end of the cylindrical gap, and the inner diameter of the active piston 9 is larger than the outer diameter of the core tube 5, the driving piston 9 is coaxially arranged in the cylindrical gap, a limiting piston a is arranged on the driving piston 9, liquid sprayed out of the first flow guide port 5a can drive one end of the limiting piston 5a to slide into the annular clamping groove 3a, a second elastic piece for driving the end part of the limiting piston 5a to slide out of the annular clamping groove 3a is arranged on the limiting piston 5a, after one end of the limiting piston 5a slides into the annular clamping groove 3a, the driving piston 9 can slide upwards relative to the outer cylinder 3 of the reamer, but at the moment, the driving piston 9 cannot slide downwards relative to the outer cylinder 3 of the reamer, so that one-way locking is realized, the reaming quality is improved, when no liquid is sprayed out (or the pressure is reduced) from the first flow guide port 5a, the limiting piston a slides out of the annular clamping groove 3a under the action of the second elastic piece, at this time, the driving piston 9 may slide downward relative to the outer reamer cylinder.

The variable diameter reamer while drilling further comprises a forced return piston b and a pressure cap c, the forced return piston b is coaxially arranged in the cylindrical gap, the upper end of the first elastic member 6 abuts against the forced return piston b, the lower end of the first elastic member 6 abuts against the reset member 2, the pressure cap c is sealed at the upper end of the cylindrical gap, a first through hole c1 and a second through hole c2 are formed in the pressure cap c, the flow guiding area of the first through hole c1 is larger than that of the second through holes c2, the first through hole c1 is communicated with the core pipe 5, the second through holes c2 are communicated with the cylindrical gap, the second through holes c2 are multiple, the second through holes c2 are uniformly arranged along the circumferential direction of the core pipe 5, a single valve 3b is arranged on the outer barrel 3 of the reamer, and a liquid inlet of the one-way valve 3b is communicated with the cylindrical gap, and the liquid inlet of the one-way valve 3b is arranged close to the first elastic part 6, the liquid outlet of the one-way valve 3b is communicated with the peripheral surface of the outer cylinder 3 of the reamer, and the one-way valve 3b plays a role in pressure relief.

Referring to fig. 6 and referring again to fig. 2, the variable diameter drill-while-drilling reamer further comprises a transmission member, the transmission member comprises a transmission member outer cylinder d, a turbine rotor e and a turbine shaft f, the turbine rotor e and the turbine shaft f are coaxially arranged in the transmission member outer cylinder d, the lower end of the turbine shaft f is coaxially and fixedly connected with the reamer outer cylinder 3, the lower end of the turbine shaft f is provided with three diversion grooves g communicated with the first through hole c1 and the second through hole c2, the diversion grooves g are circumferentially arrayed around the axis of the turbine shaft f, and the diversion direction of the diversion grooves g can be inclined to the axis of the turbine shaft f, so as to guide drilling fluid to generate (enhance) torque for driving the reamer outer cylinder 3 to rotate.

The turbine rotors e are coaxially and fixedly connected with the turbine shaft f, in the embodiment, the number of the turbine rotors e is multiple, a turbine stator h is arranged between every two vertically adjacent turbine rotors e, the turbine stator h is coaxially and fixedly connected with the inner circumferential surface of the outer cylinder 3 of the reamer, and the turbine is adopted for driving, so that the energy loss is reduced, and the reaming efficiency is improved.

The transmission part also comprises a pressure lever j and a second protection pin k which limits the movement of the pressure lever j relative to the pressure lever groove, the pressure lever j is coaxially arranged in the pressure lever groove, one part of the second protection pin k is connected with the pressure lever j and the other part of the second protection pin k is connected with the pressure lever groove, the top of the pressure lever j is provided with a stressed end penetrating through the pressure lever groove, the pressure lever j is coaxial with the first through hole c1, the outer diameter of the lower end of the pressure lever j is larger than the aperture of the upper end of the first through hole c1, when the reaming cutter 1 is clamped, the second protection pin k is sheared by a ball m which acts on the stressed end of the top of the pressure lever j under the pressure of drilling fluid, and the pressure lever j moves downwards and plugs the first through hole c1 at the center of the pressure cap c, the drilling fluid flows into the second through hole c2 on the pressure cap c and downwards extrudes the forced return piston b to force the reaming cutter 1 to return, and after the reaming cutter 1 returns, the hydraulic pressure flows out of the device through the check valve 3b on the outer cylinder 3 of the reamer, so that accidents caused by pressure building are prevented.

The working principle is as follows: the reducing adjusting structure is applied to a drilling reamer, a sliding pin slides in a closed loop combined groove to realize the positioning of the sliding pin at different vertical positions, liquid sprayed out of a first flow guide opening 5a can drive the outer side of a reaming cutter 1 to slide out of a cutter outlet groove, under the guiding action of a first guide inclined plane and a second guide line plane, the reaming cutter 1 slides out from the obliquely upper side, at the moment, the reaming cutter 1 jacks up a reset piece 2 abutted against the reaming cutter 1, at the moment, the sliding pin slides downwards relative to the closed loop combined groove, finally, the sliding pin stops sliding after sliding to the lower end of a first sliding groove 2a, and when the pressure of water flow sprayed out of the first flow guide opening 5a is reduced, so that the first driving force is smaller than the second driving force, the reset piece 2 slides downwards relative to an outer barrel 3 of the reamer, so that the sliding pin slides upwards relative to the closed loop combined groove, the sliding pin slides into the adjacent second sliding groove 2b along the inclined direction of the first guiding groove 2c, finally, the sliding pin stops sliding after sliding into the upper end of the second sliding groove 2b, at this time, the pressure of the water flow sprayed from the first flow guide port 5a is increased, so that the first driving force is greater than the second driving force, the sliding pin slides downwards again, the sliding pin slides into the second guiding groove 2d from the lower end of the second sliding groove 2b, the sliding pin slides into the adjacent first guiding groove 2c along the inclined direction of the second guiding groove 2d, so that the sliding pin slides in different first sliding grooves 2a, when the lengths of the first sliding grooves 2a into which the sliding pin slides are different, the distances of the reset piece 2 sliding upwards relative to the reamer outer cylinder 3 are also different, and therefore, the distance of the reamer 1 sliding out of the cutter groove is limited, therefore, the adjustment of the outer diameter of the cutter of the reaming cutter 1 is realized, at least two kinds of well bores with different sizes can be completed in one drilling, the tripping times are reduced, and the drilling efficiency is improved.

The above description of the present invention does not limit the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the scope of the claims of the present invention.

Claims

1. The utility model provides a structure is adjusted in reducing, is applied to while-drilling reamer on, this while-drilling reamer have reaming cutting knife, drive reaming cutting knife go out the driving source of sword, the piece that resets of drive reaming cutting knife backing tool, holding reaming cutting knife and the reamer urceolus that resets, the piece that resets and the coaxial arrangement of reamer urceolus, its characterized in that, this structure is adjusted in reducing includes:

2. The diameter-changing adjusting structure according to claim 1, wherein lengths of the plurality of first sliding grooves are sequentially increased/decreased along a circumferential direction of the restoring member.

3. A variable diameter reamer while drilling, comprising:

the reducing adjustment structure of any one of claims 1 to 2;

4. The variable diameter reamer as claimed in claim 3, further comprising a first shear pin, wherein one end of the first shear pin is coupled to the outer reamer barrel and the other end of the first shear pin is coupled to the reset member.

5. The variable diameter reamer while drilling of claim 3, wherein a plurality of annular clamping grooves are formed in the inner circumferential surface of the outer reamer cylinder, the annular clamping grooves are sequentially arranged along the axial direction of the outer reamer cylinder and are located below the cutter discharge grooves, the annular clamping grooves are located above the first flow guide port, the upper side surfaces of the annular clamping grooves are gradually inclined upwards from inside to outside, the lower side surfaces of the annular clamping grooves are perpendicular to the axial line of the core pipe, a cylindrical gap is formed between the outer reamer cylinder and the core pipe, the variable diameter reamer while drilling further comprises a core pipe cap and an active piston, the core pipe cap is arranged below the first flow guide port and is sealed at the lower end of the cylindrical gap, the active piston is coaxially arranged in the cylindrical gap, and a limit piston is arranged on the active piston, the liquid sprayed out of the first flow guide port can drive one end of the limiting piston to slide into the annular clamping groove, and a second elastic piece for driving the end part of the limiting piston to slide out of the annular clamping groove is arranged on the limiting piston.

6. The reamer as recited in claim 5, further comprising a forced return piston and a pressure cap, wherein the forced return piston is coaxially disposed in the cylindrical gap, an upper end of the first resilient member abuts against the forced return piston, a lower end of the first resilient member abuts against the return member, the pressure cap is sealed at an upper end of the cylindrical gap, the pressure cap is provided with a first through hole and a second through hole, the first through hole is in communication with the core tube, and the second through hole is in communication with the cylindrical gap.

7. The variable diameter reamer while drilling of claim 6, wherein the second through hole is a plurality of second through holes, and the plurality of second through holes are uniformly arranged along a circumferential direction of the core tube.

8. The variable diameter reamer while drilling of claim 6, wherein a one-way valve is disposed on the outer reamer barrel, an inlet of the one-way valve is in communication with the cylindrical gap, and an inlet of the one-way valve is disposed proximate the first elastomeric member, an outlet of the one-way valve is in communication with an outer circumferential surface of the outer reamer barrel.

9. The variable diameter reamer while drilling as recited in claim 8, further comprising a transmission member, wherein the transmission member comprises a transmission member outer cylinder, a turbine rotor, and a turbine shaft, the turbine rotor and the turbine shaft are both coaxially disposed in the transmission member outer cylinder, a lower end of the turbine shaft is coaxially and fixedly connected to the reamer outer cylinder, a lower end of the turbine shaft is provided with a diversion trench communicating with the first through hole and the second through hole, and the turbine rotor is coaxially and fixedly connected to the turbine shaft.

10. The variable diameter reamer while drilling as recited in claim 9, wherein the turbine shaft is provided with a pressure bar groove coaxial therewith and penetrating upper and lower end surfaces thereof, the transmission member further comprises a pressure bar and a second protection pin limiting movement of the pressure bar relative to the pressure bar groove, the pressure bar is coaxially arranged in the pressure bar groove, one part of the second protection pin is connected to the pressure bar, the other part of the second protection pin is connected to the pressure bar groove, the top of the pressure bar is provided with a stressed end penetrating through the pressure bar groove, the pressure bar is coaxial with the first through hole, and the outer diameter of the lower end of the pressure bar is larger than the diameter of the upper end of the first through hole.