CN220705626U

CN220705626U - Diameter-variable PDC drill bit

Info

Publication number: CN220705626U
Application number: CN202322400443.7U
Authority: CN
Inventors: 李维均; 宋东东; 夏宝林; 高加琼; 祝林; 陈德航; 苏婉熙; 王治文
Original assignee: Sichuan Vocational and Technical College
Current assignee: Sichuan Vocational and Technical College
Priority date: 2023-09-05
Filing date: 2023-09-05
Publication date: 2024-04-02
Anticipated expiration: 2033-09-05

Abstract

The utility model discloses a variable diameter PDC drill bit which comprises a drill bit body, a cylinder body, a male connector and a variable diameter mechanism, wherein the drill bit body, the cylinder body, the male connector and the variable diameter mechanism are sequentially arranged and communicated to form a cylindrical cavity; the drill bit body is provided with a movable blade and a blade groove, a second guide groove penetrating into the drill bit body along the radial direction of the drill bit body is arranged in the blade groove, and a first guide groove which is parallel to the radial direction of the drill bit body is arranged on the inner wall of the second guide groove; the diameter-changing mechanism comprises a wedge-shaped T-shaped groove arranged on the inner side of the movable blade, a wedge-shaped T-shaped block arranged in the wedge-shaped T-shaped groove and a motor driving unit arranged in the cylindrical cavity, wherein a guide block matched with the first guide groove is arranged on the outer wall of the wedge-shaped T-shaped groove, and the guide block enters the drill bit body through the second guide groove, and the motor driving unit is fixedly connected with the wedge-shaped T-shaped block through a guide head axially moving in the drill bit body. The utility model provides a technical scheme of PDC drill bit diameter change, which is more economical, more stable and effective and has more operability.

Description

Diameter-variable PDC drill bit

Technical Field

The utility model relates to a variable diameter PDC drill bit, in particular to a device capable of changing the diameter of the PDC drill bit, and belongs to the technical field of petroleum and natural gas drilling.

Background

The PDC drill bit is widely applied to petroleum and natural gas drilling operation due to the advantages of wider adaptive stratum, easier drilling speed lifting, fewer times of opening, firmness, reliability, no risk of roller falling, long service life and the like. When unstable formations such as gravel layers, salt paste layers, heterogeneous formations, formations with stronger plasticity and the like are drilled in the petroleum and natural gas drilling operation process, shrinkage or partial collapse of a borehole is often encountered, conventional PDC drill bit blades are fixed, the drill bit cannot be easily lifted through changing the diameter of the drill bit in the shrinkage formation, and the phenomenon of drill bit sticking often occurs, so that the difficulty of drilling is increased to a great extent, and the economic investment is obviously increased.

Problems still existing in the existing bit diameter-changing technology include: firstly, realizing reducing through pneumatic transmission, and the reducing effect is unstable; secondly, the diameter is changed through the hinge mechanism, and the drill is extremely easy to damage under the action of strong impact force during drilling, so that the diameter changing function of the drill is invalid, and the diameter changing purpose cannot be realized; thirdly, the diameter is changed through transmission technologies such as a gear rack and the like, the design is limited by a narrow space inside a drill bit, the impact strength of the drill bit is extremely difficult to ensure, and the high-strength impact in the drilling process is likely to cause the drill bit to completely lose the diameter changing function. In addition, the prior art can not realize effective control of the diameter of the drill bit through the ground control platform in time, so that the diameter of the drill bit is difficult to change.

In the prior art, the utility model patent with publication number of CN111119741A (the date of grant 2022, 3 and 15) discloses a variable diameter PDC directional drill bit, which comprises a variable diameter cutting member arranged on a drill bit body at least in a radial direction, a gear and rack transmission mechanism embedded in the drill bit body, and an elastomer sleeved on the gear and rack transmission mechanism, wherein the gear and rack transmission mechanism is adopted to realize the transfer from axial movement to radial movement. The utility model patent with publication number CN109723385A (the date of 2021, 03 and 19) discloses a PDC drill bit with diameter-keeping and reducing functions, which comprises a rotary blade arranged at the blade position of a drill bit body through a pin, wherein the rotary blade can rotate around the pin under the pushing of a lower piston, and the opening angle of the rotary blade is controlled by adjusting drilling fluid pressure so as to realize the reducing function of the drill bit.

It can be seen that the prior art does not provide a solution to the above and related problems.

Disclosure of Invention

The utility model aims to realize diameter changing of a PDC drill bit by driving the movable blade to radially stretch out and draw back in the drill bit body under the action of a motor driving unit through a wedge-shaped T-shaped groove arranged at the inner side of the movable blade and a wedge-shaped T-shaped block fixedly connected with a guide head, and provides the diameter-changing PDC drill bit which solves the problems of unstable diameter changing, easy failure of the diameter changing function, easy damage of a diameter changing mechanism and the like in the prior art and solves the problems of diameter shrinkage and clamping, difficult diameter changing and the like in the drilling process.

The utility model is realized by the following technical scheme:

the utility model provides a variable diameter PDC drill bit, its characterized in that, including setting gradually and intercommunication drill bit body, barrel and the public joint and the reducing mechanism that form cylindrical cavity, the drill bit body establish movable blade and be used for installing movable blade's blade groove, be equipped with the second guide way that prescribes a limit to movable blade telescopic direction in the blade groove, the second guide way is followed the drill bit body radially runs through to its inside, be equipped with on the blade groove inner wall with the radial parallel first guide way of drill bit body, the reducing mechanism including locate the inboard wedge T type groove of movable blade, locate wedge T type inslot and wedge angle equal wedge T type piece and fixed set up in motor drive unit in the cylindrical cavity, be equipped with on the wedge T type inslot wall with first guide way complex guide piece, and pass through the second guide way gets into in the drill bit body, motor drive unit pass through on set up in drill bit body axial motion's guide way with wedge T type piece fixed connection.

Optionally, the wedge angle ranges from 10 ° to 26 °.

Optionally, the motor drive unit includes fixed set up in the motor of cylindrical cavity lower extreme, locate transmission shaft and the direction head on the drill bit body axle center line, the motor through the pivot with the connecting axle of transmission shaft one end is connected, the direction head through the screw pair with the transmission shaft other end is connected, and along with the transmission shaft in the axial motion of drill bit body.

Optionally, at least two sinking grooves are uniformly arranged at the connecting end of the cylinder body and the male connector in the circumferential direction, and a fixing block which is matched with the sinking grooves and fixes the motor driving unit is arranged on the motor.

Optionally, a signal channel interface for receiving a control signal of the motor is further arranged on the motor.

Optionally, the motor driving unit further comprises a power supply device of the motor.

Optionally, the power supply device is a micro hydraulic generator provided with a liquid drive impeller, and the motor is connected with the micro hydraulic generator through an electric connector arranged on the micro hydraulic generator and is electrified.

Optionally, the motor is equipped with the pivot gum cover that prevents drilling fluid entering, the vice ripple sealed tube that is equipped with of lead screw, miniature hydraulic generator is equipped with the buffering safety cover that prevents the drilling fluid entering outward.

Optionally, a top tooth is provided at the top of the drill bit body, and a core tooth is provided at the inner side of the top of the movable blade.

Optionally, the top of the blade groove is provided with the strip-shaped water hole, and a nozzle is arranged between the blade grooves at the center of the top of the drill bit body.

Compared with the prior art, the utility model has the following advantages:

(1) According to the utility model, the wedge-shaped T-shaped groove is formed in the inner side of the movable blade, the wedge-shaped T-shaped blocks with equal wedge angles are arranged in the wedge-shaped T-shaped groove, the motor driving unit which enables the wedge-shaped T-shaped blocks to axially move in the drill bit body through the guide heads fixedly connected with the wedge-shaped T-shaped blocks, and the second guide groove which is arranged in the blade groove and radially penetrates into the drill bit body along the drill bit body are provided, so that the movable blade is enabled to radially stretch and retract along the drill bit body, and the purpose of reducing the drill bit is realized; the guide block and the first guide groove are matched to ensure the variable-diameter stability; the cylindrical cavity formed by communicating the drill bit body, the cylinder body and the male connector forms a protective cover for the reducing mechanism, so that the impact force on the reducing mechanism during drilling is reduced, the reducing mechanism is protected, the reducing stability of the reducing mechanism is improved, and the effectiveness of the reducing function is ensured; the wedge T-shaped groove and the wedge T-shaped block with the same wedge angle are arranged, so that the strain intensity of the reducing mechanism in the reducing process is higher, the external high-intensity impact is enough to be dealt with, the reducing mechanism is prevented from being damaged, the effectiveness of the reducing function is influenced, the effect of improving the effectiveness of the reducing is achieved, and meanwhile, the clamping phenomenon caused by different wedge angles can be avoided.

(2) According to the utility model, the wedge angle is in the range of 10-26 degrees, so that a better reducing effect in a limited space is achieved, the strain intensity of the reducing mechanism arranged in a limited abrupt space is higher, the stability of the reducing mechanism is improved, and the reducing mechanism is prevented from being damaged in the drilling process.

(3) According to the utility model, the guide head moves axially on the drill bit body through the motor fixedly arranged at the lower end of the cylindrical cavity, the transmission shaft and the screw pair arranged on the axis of the drill bit body, so that the wedge-shaped T-shaped block is driven to move axially on the drill bit body, and the wedge-shaped T-shaped block drives the movable blade to extend radially on the drill bit body.

(4) According to the utility model, at least two sinking grooves are uniformly arranged at the connecting end of the cylinder body and the male connector in the circumferential direction, and the motor is provided with the fixing blocks matched with the sinking grooves, so that the motor driving unit is fixed in the cylindrical cavity, and the diameter-changing stability of the drill bit is ensured.

(5) According to the PDC drill bit diameter-changing device, the signal channel interface for receiving the control signal of the motor is arranged on the motor, and the motor is controlled to rotate forward or reversely by the control signal sent by the ground control system, so that the transmission shaft is driven to rotate and the guide head is driven to axially move in the drill bit body, and the wedge-shaped T-shaped block fixedly connected with the guide head drives the blades to radially stretch out and draw back in the drill bit body, so that the PDC drill bit diameter-changing purpose is achieved.

(6) According to the utility model, the power supply device is arranged, so that the diameter changing function of the diameter changing mechanism is effectively supported by power supply, and the diameter changing of the drill bit is ensured to be successfully realized.

(7) According to the utility model, the power supply device is set as the miniature hydraulic power generator of the liquid drive impeller, and the drilling liquid is utilized to generate power, so that the recycling of the circulating kinetic energy of the drilling liquid in the drilling process is realized, and the energy waste in the drilling process is avoided.

(8) According to the utility model, the motor is provided with the rotating shaft rubber sleeve into which drilling fluid enters, the corrugated sealing pipe is arranged outside the screw pair, and the buffer protection cover for preventing the drilling fluid from entering is arranged outside the miniature hydraulic generator, so that the effects of further ensuring the stability of the reducing mechanism and the effectiveness of the reducing function are achieved, and adverse effects of external factors on the reducing mechanism are avoided.

(9) According to the utility model, the strip-shaped water hole is arranged at the top of the blade groove, and the nozzle is arranged between the blade groove at the central position of the top of the drill bit body, so that the effect of preventing the diameter-changing mechanism from being blocked is achieved, the stability and the effectiveness of the diameter-changing mechanism are further improved, and the risk of blocking the drill in drilling operation is reduced.

(10) According to the utility model, the top teeth are arranged on the top of the drill bit body, and the core teeth are arranged on the inner side of the top of the movable blade to fill the blank of the central area of the drill bit caused by diameter change, so that a rock column is formed along the axial direction of the drill bit in the drilling process to cause axial impact on the drill bit, damage is caused to the drill bit body, and the smooth running of drilling operation is influenced; and through the setting of top tooth with the heart tooth is in axial and circumference is to the compound breakage of rock pillar, has played preventing that the rock pillar from forming, has avoided the drill bit damage, extension drill bit life-span's effect, has still played simultaneously and has promoted drilling efficiency, reduced economic loss's effect.

In summary, the utility model has the advantages of simple structure and low manufacturing cost, and enhances the strain intensity of the reducing mechanism, thereby effectively improving the effectiveness and stability of the reducing function of the drill bit, simultaneously playing the roles of improving the drilling operation efficiency and reducing the drilling operation cost, and providing a more economical, more stable and effective technical scheme with more operability for effectively solving a series of problems of difficult reducing, unstable reducing, easy failure of the reducing function, easy damage of the reducing mechanism and the like of the existing drilling operation.

Drawings

FIG. 1 is a schematic view of the structure of a drill bit before diameter change;

FIG. 2 is a schematic view of the structure of the drill bit after diameter change;

FIG. 3 is a top view of the drill bit prior to diameter modification;

FIG. 4 is a top view of the drill bit after diameter change;

FIG. 5 is a cross-sectional view of the drill bit prior to diameter modification;

FIG. 6 is a cross-sectional view of the drill bit after diameter change;

FIG. 7 is a schematic view of the structure of the bit body;

FIG. 8 is a cross-sectional view of a bit body;

FIG. 9 is a schematic view of a movable blade configuration;

FIG. 10 is a schematic view of the structure of the guide head;

FIG. 11 is a schematic view of the motor drive unit mated with the movable blade;

FIG. 12 is a schematic structural view of a cylinder;

FIG. 13 is a schematic view of the structure of a male connector;

Fig. 14 is a schematic structural view of the motor driving unit;

FIG. 15 is a schematic view of the motor drive unit with the buffer protection cover removed;

FIG. 16 is a schematic diagram of the external configuration of the power supply and power motor;

FIG. 17 is a schematic view of the structure of the drive shaft in the motor drive unit;

FIG. 18 is a schematic view of a roof tooth and core tooth composite crushed core rock string;

the drilling bit comprises a drilling bit body, a 110-blade groove, a 111-first guide groove, a 112-strip-shaped water hole, a 113-second guide groove, a 120-top tooth hole, a 130-first interface, a 140-nozzle, a 200-movable blade, a 210-guide block, a 220-wedge-shaped T-shaped groove, a 300-cylinder body, a 310-first connector, a 320-second interface, a 321-sink groove, a 400-male connector, a 410-male cone thread, a 420-second connector, a 510-micro hydraulic generator, a 511-liquid drive impeller, a 512-electric connection hole, a 513-plug pin, a 520-motor, a 521-fixed block, a 522-electric connector, a 523-signal channel interface, a 524-plug hole, a 525-rotating shaft, a 530-transmission shaft, a 531-external screw thread, a 532-connecting shaft, a 540-guide head 541-wedge-shaped T-shaped block, 542-internal screw thread, a 550-buffer protection cover, 560-corrugated pipe, a 570-rotating shaft rubber sleeve, 600-top tooth, a 700-cutting tooth, and 800-core tooth.

Detailed Description

The present utility model will be described in further detail with reference to examples, but embodiments of the present utility model are not limited thereto.

Example 1:

as shown in the structure of fig. 1 to 11, the embodiment discloses a variable diameter PDC drill bit, which comprises a drill bit body 100, a barrel 300, a male connector 400 and a variable diameter mechanism, wherein the drill bit body 100, the barrel 300, the male connector 400 and the variable diameter mechanism are sequentially arranged and communicated to form a cylindrical cavity;

the drill bit body 100 is provided with a movable blade 200 and a blade groove 110 for installing the movable blade 200, a second guide groove 113 for limiting the telescopic direction of the movable blade 200 is arranged in the blade groove 110, the second guide groove 113 penetrates into the drill bit body 100 along the radial direction, and a first guide groove 111 which is parallel to the radial direction of the drill bit body 100 is arranged on the inner wall of the blade groove 110;

the reducing mechanism comprises a wedge-shaped T-shaped groove 220 arranged on the inner side of the movable blade 200, a wedge-shaped T-shaped block 541 which is arranged in the wedge-shaped T-shaped groove 220 and is equal to the wedge angle of the wedge-shaped T-shaped groove 220, and a motor driving unit which is arranged in the cylindrical cavity and is fixedly connected with the cylindrical cavity, wherein a guide block 210 matched with the first guide groove 111 is arranged on the outer wall of the wedge-shaped T-shaped groove 220, the wedge-shaped T-shaped groove 220 enters into the drill bit body 110 through the second guide groove 113, a guide head 540 which axially moves in the drill bit body 100 is arranged on the motor driving unit, the guide head 540 is fixedly connected with the wedge-shaped T-shaped block 541 in the drill bit body 110 and drives the wedge-shaped T-shaped block 541 to axially move in the drill bit body 100, and meanwhile, the wedge-shaped T-shaped block 541 drives the movable blade 200 to radially stretch out and draw back in the drill bit body 100 through the wedge-shaped T-shaped groove 220.

In this embodiment, the sections of the movable blades 200 are all fan-shaped, after the diameter is expanded (i.e. the diameter of the drill bit is increased), a gap is formed between the movable blades 200 and the drill bit body 100, and if no external factors interfere, the gap may be blocked by silt to prevent the diameter of the drill bit from being changed when drilling in soft stratum, therefore, when drilling in these strata, the movable blades 200 with rectangular sections are recommended, so that the movable blades 200 are prevented from being affected by rock debris and the like when the drill bit body 100 is radially expanded and contracted, and the diameter changing function can be ensured when the diameter needs to be changed (i.e. the diameter of the drill bit is reduced or reduced). Of course, the telescopic parts can be arranged on the inner wall of the blade groove 110 to fill the gaps, so that the problem of failure of the diameter-changing function of the drill bit caused by sediment blockage can be solved. In addition, devices such as water holes and nozzles can be arranged in the blade grooves, and the gap is flushed by utilizing fluid effect, so that the aims of preventing sediment accumulation and avoiding gap blockage are fulfilled.

In this embodiment, as shown in fig. 5, 6 and 9, the wedge-shaped T-shaped groove 220 and the wedge of the wedge-shaped T-shaped groove 220 are upward, and in the initial state, as shown in fig. 5, the wedge-shaped T-shaped block 541 is disposed at the lowermost end (i.e., the end with a wider wedge-shaped) of the wedge-shaped T-shaped groove 220, and there is no gap between the movable blade 200 and the blade groove 110; at this time, the diameter of the drill bit is the smallest.

Operating state 1 (while drilling): as shown in fig. 2, 4 and 6, when drilling, the diameter of the drill bit needs to be adjusted to be the same as the set size of the borehole, the motor driving unit is started to drive the guide head 540 to move upwards in the axial direction of the drill bit body 100, the wedge-shaped T-shaped block 541 is driven to move upwards in the axial direction of the drill bit body 100, and the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped slot 220 and the movable blade 200 connected with the wedge-shaped T-shaped slot to move outwards in the radial direction of the drill bit body 100, so that the diameter of the drill bit is increased until the diameter is increased to be the same size as the set borehole, and then the motor driving unit is closed, so that normal drilling operation can be started.

Working state 2 (when encountering a reduced section of the wellbore or when stuck): as shown in fig. 1, 3 and 5, when encountering a reduced diameter section of a borehole, it is necessary to reduce the diameter of the borehole, start the motor driving unit, drive the guide head 540 to move axially downward in the bit body 100, and drive the wedge-shaped T-shaped block 541 to move axially downward in the bit body 100, and the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped slot 220 and the movable blade 200 connected thereto to move radially inward in the bit body 100, so as to reduce the diameter of the borehole until the diameter is reduced to a set size, and then close the motor driving unit to perform secondary drilling or tripping.

Working state 3 (at the time of tripping): as shown in fig. 1, 3 and 5, when the drill is to be started, the diameter of the drill needs to be reduced, the motor driving unit is started to drive the guide head 540 to move downwards in the axial direction of the drill body 100, the wedge-shaped T-shaped block 541 is driven to move downwards in the axial direction of the drill body 100, the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped groove 220 and the movable blade 200 connected with the wedge-shaped T-shaped groove to move inwards in the radial direction of the drill body 100, so that the diameter of the drill is reduced, and the motor driving unit is closed again until the diameter is reduced to a set size, and the drill starts. Under normal conditions, the drill pulling operation can be performed without reducing, but if the drill is pulled after the diameter reduction operation is performed, the gap between the drill and the well wall is properly widened, the risk of drill sticking during the drill pulling can be effectively reduced, the drill pulling speed can be properly increased, and the drill pulling efficiency is improved.

During daily storage (i.e., in a non-operating state), the drill bit can be restored to an initial state (i.e., the diameter of the drill bit is reduced to a minimum), so that the normal use and diameter change of the subsequent drill bit are prevented from being affected by the invasion of foreign matters into the gap between the movable blade 200 and the blade groove 110 during the storage process.

The working principle of the variable diameter PDC drill bit is as follows: the movable blade 200 is movably installed in the blade groove 110 formed in the drill bit body 100, the wedge-shaped T-shaped groove 220 is formed in the inner side of the movable blade 200, the wedge-shaped T-shaped T-shaped block which has the same wedge angle and is fixedly connected with the guide head 540 is arranged in the wedge-shaped T-shaped groove 220, the guide head 540 is driven to ascend or descend in the axial direction of the drill bit body 100 by controlling the motor driving unit, the guide head 540 is further driven to ascend or descend by the wedge-shaped T-shaped block 541 fixedly connected with the guide head, meanwhile, the wedge-shaped T-shaped block 541 slides along the wedge-shaped T-shaped groove 220 formed in the inner side of the movable blade 200, and as the distance between the wedge-shaped T-shaped block 541 and the axial lead of the guide head 540 is constant, the wedge-shaped T-shaped block 541 moves up and down and drives the movable blade 200 to move in a radial direction of the drill bit body 100, so that the purpose of changing the diameter of the PDC drill bit is realized.

The motor driving unit in this embodiment mainly includes a motor and a driving device, where the driving device is only required to drive the wedge-shaped T-shaped block 541 to move in a straight line in the axial direction of the drill bit body 100; the motor may be a linear motor, or a combination of a motor and a conversion mechanism (such as a mechanical mechanism of a screw rod, etc.), and the purpose of the motor is mainly to use the motor as a kinetic energy source, so as to achieve the purpose of driving the guide head 540 and the wedge-shaped T-shaped block 541 fixedly connected with the guide head to move in the axial direction of the drill bit body 100, so long as the motor, the conversion device, the driving device, etc. capable of realizing the linear motion of the wedge-shaped T-shaped block 541 in the axial direction of the drill bit body 100 are applicable to the motor driving unit of the present embodiment.

In the practical application process, the length of the working time of the motor driving unit can be controlled to control the distance of the guide head 540 moving up and down, so that various reducing operations of any reducing value can be realized in the maximum range of the variable diameter, full-size drilling suitable for boreholes with different sizes can be realized, the problem of drill bit sticking caused by shrinkage or partial collapse of the boreholes can be solved, and the drilling operation efficiency is further improved.

Further, in order to make the diameter-changing effect of the drill bit better and more stable, and adapt to the limited diameter-changing space of the drill bit, the wedge angles of the wedge-shaped T-shaped groove 220 and the wedge-shaped T-shaped block 541 are not only equal, but also preferably set between 10 degrees and 26 degrees, and the optimal angle range obtained through experimental comparative analysis is between 16.2 degrees and 17.4 degrees, and the diameter-changing effect is slightly reduced between 10 degrees and 16 degrees or between 17.6 degrees and 26 degrees, but the diameter-changing effect is not great.

Simulation experiments show that the influences of factors such as the wedge angle of the wedge-shaped T-shaped groove 220 and the wedge-shaped T-shaped block 541, the length of the wedge-shaped T-shaped groove 220 (namely the length of the slope surface), the revolution of the motor 520 and the like on the diameter change of the drill bit are shown in the following table:

it should be noted that the above data are not all experimental data of the simulation experiment, but only node data which are typical.

Effect of wedge angle on bit diameter variation:

the 8 1/2in drill bit actually used in drilling operation (i.e. the diameter of the drill bit is 215.9 mm), the length of the variable diameter is about 10mm by taking the wedge-shaped T-shaped groove with the length of 60mm as an example, and the drill bit can be easily and economically lifted when the diameter of the drill bit needs to be increased by 6% -12% (12.95 mm-25.91 mm) according to the data reflected by the last two well bores for well drilling. When the wedge angle is set between 0 degrees and 10 degrees, the problem that the drill bit is blocked again in the process of tripping can still occur because the diameter-reducing range is smaller and the condition of the diameter-reducing requirement of the drilled hole cannot be met, so that the angle less than 10 degrees is considered to be not within a reasonable angle range. When the wedge angle is set higher than 26 °, although a larger range of reducing effect can be obtained, the requirement on the drilling cost is also higher, and the larger range of reducing causes the reducing mechanism such as the wedge-shaped T-shaped groove 220, the wedge-shaped T-shaped block 541 and the motor driving unit to occupy more internal space of the drill bit (i.e. the internal space of the cylindrical cavity), which not only affects the circulation of drilling fluid, but also may cause interference between the reducing mechanism and the inner wall of the drill bit.

Effect of wedge length (ramp length) on bit diameter variation:

tests show that the length of the wedge-shaped T-shaped groove 220 has a larger influence on the reducing, and the length of the wedge-shaped T-shaped groove 220 is set in the following range: 50mm ~ 80mm, the best length is: 60mm; the length of the wedge-shaped T-shaped block 541 has very little influence on the reducing effect, but if the length is smaller than 30mm, the bearing capacity of the wedge-shaped T-shaped block 541 is in a dangerous value state, the safety coefficient is lower, and if the length is larger than 40mm, the situation that the drill bit is reduced to a set size and interferes with the inner wall of the drill bit can occur, so that the length of the wedge-shaped T-shaped block 541 is set within the range of: 30 mm-40 mm, and ensuring that the diameter changing process can be smooth.

Effects of motor 520 speed bit diameter variation:

simulation experiments show that the movable blade 200 is not required to be driven to change diameter in the drilling process, drilling can be stopped and lifting is carried out upwards according to the drilling pressure value displayed by the ground platform when the diameter shrinkage and drilling clamping occur, at this moment, the rotating speed of the motor 520 has no obvious influence on the diameter changing effect, only the length of the wedge-shaped T-shaped groove 220 is required to be fully considered when the rotating speed of the motor 520 is controlled, the diameter is not influenced within the length range, and the simulation experiment is carried out: the rotation speed of the motor 520 is controlled at 300r/min, namely 5r/s, and the screw pitch P=4 of the lead screw pair of the power transmission rod.

Further, as shown in fig. 5, 6 and 14, in order to make the diameter of the drill more stable, the motor driving unit in this embodiment includes a motor 520 fixedly disposed at the lower end of the cylindrical cavity, a transmission shaft 530 disposed on the axis of the drill body 100, and a guide head 540, where the motor 520 is connected to a connection shaft 532 at one end of the transmission shaft 530 through a rotation shaft 525, and the guide head 540 is connected to the other end of the transmission shaft 530 through a screw pair and moves axially with the transmission shaft 530 in the drill body 100.

In this embodiment, considering that the drilling operation cannot be affected by the diameter change of the drill bit, the diameter change operation can only be completed in a limited space, and the transmission shaft 530 and the screw pair (i.e. the screw transmission mechanism) are adopted to convert the rotary motion (i.e. the rotation of the motor 520) into the linear motion of the guide head 540, in the prior art, many mechanisms capable of achieving this purpose, such as a cam mechanism, a roller mechanism, a sliding table mechanism, a crank rocker mechanism, and the like, can achieve the purpose of converting the rotary motion into the linear motion, so as long as the mechanism capable of converting the rotary motion into the linear motion can be applied to this embodiment.

The working state is as follows when in use:

operating state 1 (while drilling): as shown in fig. 2, 4 and 6, when drilling, the diameter of the drill bit needs to be adjusted to be the same as the set size of the well bore, the motor 520 is started to make the motor 520 rotate forward and drive the transmission shaft 530 to rotate forward, then the guide head 540 moves upwards axially in the drill bit body 100 under the action of the screw pair, the guide head 540 drives the wedge-shaped T-shaped block 541 to move upwards axially in the drill bit body 100, and simultaneously, the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped groove 220 and the movable blade 200 connected with the wedge-shaped T-shaped groove to move outwards in the radial direction of the drill bit body 100, so that the diameter of the drill bit is increased until the diameter is increased to be the same size as the set well bore, and then the motor 520 is closed, so that normal drilling operation can be started.

Working state 2 (when encountering a reduced section of the wellbore or when stuck): as shown in fig. 1, 3 and 5, when encountering a reduced diameter section of a borehole, the diameter of the drill bit needs to be reduced, the motor 520 is started, the motor 520 is reversed and drives the transmission shaft 530 to rotate reversely, the guide head 540 is driven to move axially downwards in the drill bit body 100 by the action of the screw pair, the wedge-shaped T-shaped block 541 is driven to move axially downwards in the drill bit body 100, and the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped groove 220 and the movable blade 200 connected with the wedge-shaped T-shaped groove to move radially inwards in the drill bit body 100, so that the diameter of the drill bit is reduced until the diameter is reduced to a set size, and then the motor 520 is closed, so that secondary drilling operation or tripping operation can be started.

Working state 3 (at the time of tripping): as shown in fig. 1, 3 and 5, when the drill is started, the diameter of the drill bit needs to be reduced, the motor 520 is started, the motor 520 is reversed and drives the transmission shaft 530 to rotate reversely, the guide head 540 is axially moved downwards in the drill bit body 100 by the action of the screw pair, the wedge-shaped T-shaped block 541 is driven to axially move downwards in the drill bit body 100, and the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped groove 220 and the movable blade 200 connected with the wedge-shaped T-shaped groove to radially and inwards move along the drill bit body 100, so that the diameter of the drill bit is reduced until the diameter is reduced to a required size, and the motor 520 is closed again, so that the drill starting operation can be started. In general, the drill lifting operation can be performed under the condition that the drill is not changed in diameter, but in order to reduce the risk of drill sticking during the drill lifting as much as possible, the drill is preferably subjected to the diameter reducing operation, the drill is lifted after the distance between the drill and the wall of the well is increased, the occurrence of the drill sticking phenomenon can be avoided, the drill lifting speed is also properly accelerated, and therefore the efficiency of the drilling operation is improved.

The working principle of the variable diameter PDC drill bit is as follows: by movably mounting the movable blade 200 in the blade groove 110 provided in the drill bit body 100, a wedge-shaped T-shaped groove 220 is provided inside the movable blade 200, and a wedge-shaped T-shaped block having the same wedge angle and fixedly connected with a guide head 540 is provided inside the wedge-shaped T-shaped groove 220, wherein the guide head 540 is connected with a motor 520 through a screw pair and a transmission shaft 530; during drilling operation, the motor 520 is controlled to rotate positively and negatively, so that the transmission shaft 530 connected with the motor is driven to rotate positively and negatively, the rotary motion transmitted by the transmission shaft 530 is converted into the linear motion of the guide head 540 in the axial direction of the drill bit body 100 through the action of the screw pair, the guide head 540 drives the wedge-shaped T-shaped block 541 fixedly connected with the guide head 540 to move in the axial direction of the drill bit body 100, and the distance between the wedge-shaped T-shaped block 541 and the axial lead of the guide head 540 is constant, and the wedge-shaped sliding between the wedge-shaped T-shaped block 541 and the wedge-shaped T-shaped groove 220 enables the wedge-shaped T-shaped block 541 to move up and down and simultaneously drives the movable cutter blade 200 to move in the radial expansion and contraction direction of the drill bit body 100, so that the diameter of the PDC drill bit is changed.

In the practical application process, the length of the forward and backward rotation time of the motor 520 can be controlled to control the up and down movement distance of the guide head 540, so that various reducing operations of any reducing value can be realized in the maximum range of the variable diameter, the full-size drilling suitable for boreholes with different sizes can be realized, the problem of drill bit sticking caused by the shrinkage or partial collapse of the boreholes can be solved, the drilling operation efficiency is further improved, and the economic loss caused by the sticking is reduced.

Further, as shown in the structures of fig. 5, 6 and 12, in order to make the motor driving unit be more stably fixed in the cylindrical cavity, thereby ensuring the stability and effectiveness of the diameter variation of the drill, at least two countersunk grooves 321 are uniformly arranged at the connecting end of the cylinder 300 and the male connector 400 in the circumferential direction, and a fixing block 521 which is matched with the countersunk grooves 321 and fixes the motor driving unit is arranged on the motor 520.

In this embodiment, in order to prevent the motor driving unit from maintaining a better state all the time during the drilling operation, so as to avoid the failure of the reducing function caused by the dislocation or falling in the cylindrical cavity, 3 pairs of mutually matched sinking grooves 321 and fixing blocks 521 are uniformly arranged at the connecting end of the cylinder 300 and the male connector 400 in the circumferential direction. It follows that a fixing structure ensuring the realization of the diameter changing function is applicable to the present embodiment as long as the motor drive unit can be fixed.

Further, as shown in the structures in fig. 5, 14, 15 and 16 (a), in order to receive a control signal sent by the ground control system to control the motor 520 to rotate forward or reverse, so as to drive the transmission shaft 530 to rotate and the guide head 540 to move axially on the drill bit body, a wedge-shaped T-shaped block fixedly connected with the guide head drives the blade to extend and retract in the radial direction of the drill bit body, so as to control the diameter variation of the drill bit by the ground platform, and a signal channel interface 523 for receiving the control signal of the motor 520 is provided on the motor 520.

The working state is as follows when in use:

operating state 1 (while drilling): as shown in fig. 2, 4 and 6, when drilling, the drill bit diameter needs to be adjusted to the same size as the set borehole, and when the motor 520 receives a forward rotation signal from the surface control system through the signal path interface 523, the motor 520 rotates forward. And drives the transmission shaft 530 to rotate forward, and then the guide head 540 moves upwards in the axial direction of the drill bit body 100 under the action of the screw pair, the guide head 540 drives the wedge-shaped T-shaped block 541 to move upwards in the axial direction of the drill bit body 100, and simultaneously, the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped groove 220 and the movable blade 200 connected with the wedge-shaped T-shaped groove to move outwards in the radial direction of the drill bit body 100, so that the diameter of the drill bit is increased until the diameter is increased to the same size of the set borehole, and when the signal channel interface 523 receives a stop signal sent by the ground control system, the motor 520 stops working, and normal drilling operation can be started.

Working state 2 (when encountering a reduced section of the wellbore or when stuck): as shown in fig. 1, 3 and 5, when encountering a reduced diameter section of a borehole, the diameter of the drill bit needs to be reduced, when the motor 520 receives a reverse signal sent by the ground control system through the signal channel interface 523, the motor 520 reverses and drives the transmission shaft 530 to reverse, then the guide head 540 moves axially downwards in the drill bit body 100 through the action of the screw pair, and drives the wedge-shaped T-shaped block 541 to move axially downwards in the drill bit body 100, and the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped groove 220 and the movable blade 200 connected with the wedge-shaped T-shaped groove to move radially inwards in the drill bit body 100, so that the diameter of the drill bit is reduced until the diameter is reduced to a set size, and when the signal channel interface 523 receives a stop signal sent by the ground control system, the motor 520 stops drilling operation, so that secondary operation or drill-out operation can be started.

Working state 3 (at the time of tripping): as shown in fig. 1, 3 and 5, when the diameter of the drill bit needs to be reduced during the drilling, when the motor 520 receives a reverse signal sent by the ground control system through the signal channel interface 523, the motor 520 reverses and drives the transmission shaft 530 to reverse, then the guide head 540 moves axially downwards in the drill bit body 100 under the action of the screw pair and drives the wedge-shaped T-shaped block 541 to move axially downwards in the drill bit body 100, and the wedge-shaped T-shaped block 541 drives the wedge-shaped T-shaped groove 220 and the movable blade 200 connected with the wedge-shaped T-shaped groove to move radially inwards in the drill bit body 100, so that the diameter of the drill bit is reduced, and when the signal channel interface 523 receives a stop signal sent by the ground control system until the diameter is reduced to a required size, the motor 520 stops working, and the drilling operation can be started. In general, the drill lifting operation can be performed under the condition that the drill is not changed in diameter, but in order to reduce the risk of drill sticking during the drill lifting as much as possible, the drill is preferably subjected to the diameter reducing operation, the drill is lifted after the distance between the drill and the wall of the well is increased, the occurrence of the drill sticking phenomenon can be avoided, the drill lifting speed is also properly accelerated, and therefore the efficiency of the drilling operation is improved.

The working principle of the variable diameter PDC drill bit is as follows: by movably mounting the movable blade 200 in the blade groove 110 provided in the drill bit body 100, a wedge-shaped T-shaped groove 220 is provided inside the movable blade 200, and a wedge-shaped T-shaped block having the same wedge angle and fixedly connected with a guide head 540 is provided inside the wedge-shaped T-shaped groove 220, wherein the guide head 540 is connected with a motor 520 through a screw pair and a transmission shaft 530; during drilling operation, the motor is started, rotated forwards, rotated backwards and stopped by the control signal sent by the ground control system, the motor 520 receives the control signal sent by the ground control system through the signal channel interface 523 and rotates forwards and backwards according to the control signal, so that the transmission shaft 530 connected with the motor is driven to rotate forwards and backwards, the rotary motion transmitted by the transmission shaft 530 is converted into the linear motion of the guide head 540 in the axial direction of the drill bit body 100 by the action of the screw pair, the guide head 540 drives the wedge-shaped T-shaped block 541 fixedly connected with the guide head 540 to axially move in the drill bit body 100, and the distance between the wedge-shaped T-shaped block 541 and the axial lead of the guide head 540 is constant, and the wedge-shaped sliding between the wedge-shaped T-shaped block 541 and the wedge-shaped T-shaped groove 220 enables the wedge-shaped T-shaped block 541 to vertically move and simultaneously drives the movable blade 200 to radially stretch along the drill bit body 100, so that the ground control system can control the diameter change of the drill bit.

In the practical application process, the length of the forward and backward rotation time of the motor 520 can be controlled through the ground control system to control the distance of the guide head 540 moving up and down, so that the diameter-changing operation of any diameter-changing value in the maximum range of the variable diameter can be realized, the full-size drilling suitable for boreholes with different sizes can be realized, the problem of drill sticking caused by the shrinkage or partial collapse of the boreholes can be solved, meanwhile, the efficiency of drilling operation is further improved, and the economic loss caused by the sticking is reduced.

Example 2:

as shown in fig. 5, 6, 11 and 14 to 16, this embodiment discloses a motor-driven variable diameter PDC drill bit, and on the basis of embodiment 1, the motor driving unit further includes a power supply device of the motor 520. The power supply device is arranged to enable the diameter changing mechanism to realize the diameter changing function to be effectively supported by power supply, and ensure that the diameter changing of the drill bit is smoothly realized. Thus, as long as the above-described requirements can be satisfied, the power supply device such as: a battery, a micro vibration generator, a micro hydraulic generator, or the like, as long as a device capable of supplying power to the motor 520 used for the bit diameter change is applicable to the present embodiment.

Further, in order to fully utilize the resources, the power supply device used in this embodiment is a micro-hydraulic generator 510 provided with a hydraulic impeller 511, and the motor 520 is connected to and electrified by an electrical connector 522 provided on the micro-hydraulic generator 510. The miniature hydraulic generator with the liquid drive impeller 511 converts the kinetic energy of drilling fluid circulation into the electric energy for supplying power to the motor 520, and the motor 520 is connected with the electric connector 522 to supply power to the miniature hydraulic generator, so that the power supply device 510 rotates under the action of the drilling fluid to generate power by means of hydraulic impact force and provides continuous electric energy with proper voltage for the motor 520 and the drill bit diameter variation under the drive of the motor 522, self power supply in the drill bit diameter variation process is realized, namely the kinetic energy of drilling fluid circulation is converted into the electric energy, namely, the resource is reused, and adverse effects on drilling operation caused by long-distance wiring power supply are avoided.

Furthermore, in order to ensure that the micro hydraulic power generator 510, the motor 520 and the transmission device can work normally in the diameter-changing process of the drill bit, the tightness of the micro hydraulic power generator 510, the motor 520 and the transmission device is improved, and the interference of external factors, such as the damage of well fluid entering the power supply device 510 and the motor 520 or the influence of the well fluid on the normal working state, is prevented; or, the silt during drilling affects the transmission function and effect of the transmission shaft 530 and the screw pair, etc.; as shown in fig. 11, 14 and 15, a buffer protection cover 550 for preventing drilling fluid from entering is provided outside the power supply device 510, the motor 520 is provided with a rotating shaft rubber sleeve 570 for preventing drilling fluid from entering, and a bellows seal tube 560 is provided outside the screw pair.

Further, in order to prevent the formation of the rock pillar, avoid the damage of the drill bit, and prolong the service life of the drill bit, the blank of the central area of the drill bit caused by the arrangement of the movable blade 200 is filled, so that the rock pillar is formed along the axial direction of the drill bit in the drilling process to cause axial impact to the drill bit, thereby damaging the drill bit body, affecting the smooth running of drilling operation, even causing underground accidents, and the like. As shown in fig. 3, 4, 8, 9 and 18, a top tooth hole 120 for installing a top tooth 600 is provided at a top center position of the drill bit body 100, cutting teeth 700 and core teeth 800 are provided on the movable blade 200, and the core teeth 800 are provided at an inner side of a top portion of the movable blade 200, and rock columns are compositely crushed in an axial direction and a circumferential direction through the arrangement of the top teeth 600 and the core teeth 800, thereby effectively avoiding the formation of the rock columns at the center position of the drill bit, and further improving drilling efficiency and reducing economic loss.

Further, as shown in fig. 3, 4, 7 and 8, in order to prevent the diameter-variable mechanism from being blocked, and prevent the drill bit body 100 from accumulating rock debris on the blade groove 110, the diameter-variable mechanism is blocked by the introduced diameter-variable mechanism, and even damage to the diameter-variable mechanism occurs, the strip-shaped water hole 112 is formed in the top of the blade groove 110, and the nozzle 140 is formed between the blade grooves 110 in the central position of the top of the drill bit body 100. The purposes of cleaning the drill bit and ensuring the diameter-changing function of the drill bit are achieved, and the stability and the effectiveness of the diameter-changing mechanism are further improved, so that the drill sticking risk in drilling operation is further reduced.

In this embodiment, as shown in fig. 5, 6 and 9, the wedge-shaped T-shaped groove 220 and the wedge of the wedge-shaped T-shaped groove 220 are upward, and in the initial state, as shown in fig. 5, the wedge-shaped T-shaped block 541 is disposed at the lowest end (i.e., the end with a wider wedge-shaped) of the wedge-shaped T-shaped groove 220, and no gap exists between the movable blade 200 and the blade groove 110, so that the diameter of the drill bit is the smallest.

The working principle of the variable diameter PDC drill bit is as follows: by movably mounting the movable blade 200 in the blade groove 110 provided in the drill bit body 100, a wedge-shaped T-shaped groove 220 is provided inside the movable blade 200, and a wedge-shaped T-shaped block having the same wedge angle and fixedly connected with a guide head 540 is provided inside the wedge-shaped T-shaped groove 220, wherein the guide head 540 is connected with a motor 520 through a screw pair and a transmission shaft 530; during drilling operation, the motor 520 after being electrified drives the transmission shaft 530 connected with the motor to rotate positively and negatively by controlling the motor to rotate positively and negatively, and then the rotary motion transmitted by the transmission shaft 530 is converted into the linear motion of the guide head 540 in the axial direction of the drill bit body 100 by the action of the screw pair, so that the guide head 540 drives the wedge-shaped T-shaped block 541 fixedly connected with the guide head 540 to move in the axial direction of the drill bit body 100, and the distance between the wedge-shaped T-shaped block 541 and the axial lead of the guide head 540 is constant, and the wedge-shaped sliding between the wedge-shaped T-shaped block 541 and the wedge-shaped T-shaped groove 220 enables the wedge-shaped T-shaped block 541 to move up and down and simultaneously drives the movable blade 200 to move in a radial expansion mode along the drill bit body 100, so that the PDC drill bit is changed in diameter is realized.

In this embodiment, the micro hydraulic power generator 510 is provided with the hydraulic impeller 511, during the drilling process, the micro hydraulic power generator 510 rotates to generate power under the action of the drilling fluid by means of the hydraulic impact force, and provides electric power for the motor 520 through the electric connector 522, that is, the hydraulic power generation is based on the impact energy of the drilling fluid, in this embodiment, if the electric storage and discharge device is not provided, the energy source for continuously driving the drill bit to change diameter cannot be effectively ensured, and the reducing mechanism cannot be continuously used for a long time, so as to affect the diameter changing function of the drill bit. In order to make the diameter-changing function of the drill bit more stable and effective, it is recommended to use a miniature hydraulic generator 510 capable of storing and discharging electricity in actual use so as to ensure that the drill bit has the diameter-changing function in a rotating or non-rotating state.

In the practical application process, the length of the forward and backward rotation time of the motor 520 can be controlled to control the up and down movement distance of the guide head 540, so that various reducing operations of any reducing value can be realized in the maximum range of the variable diameter, full-size drilling suitable for boreholes with different sizes can be realized, the problems of drill bit sticking and the like caused by the shrinkage or partial collapse of the boreholes can be solved, the efficiency of drilling operation is further improved, and the economic loss caused by the sticking of the drill bit is reduced.

Example 3:

as shown in the structures of fig. 1 to 18, this embodiment discloses a preferred embodiment of a motor-driven variable diameter PDC bit, which includes: bit body 100, movable blade 200, cylinder 300, male connector 400, and motor drive unit;

bit body 100: as shown in the structure of fig. 1 to 8, the drill bit body 100 is provided with a plurality of blade grooves 110, the blade grooves 110 penetrate through the drill bit body 100, first guide grooves 111 are arranged at two sides of the blade grooves 110, strip-shaped water holes 112 are formed in positions, close to the center of the drill bit body 100, of the blade grooves 110, second guide grooves 113 are formed in positions, below the strip-shaped water holes 112, in the middle of the blade grooves 110, top tooth holes 120 for mounting top teeth 600 are formed in the top of the drill bit body 100, a first interface 130 is formed in the bottom of the drill bit body 100, and nozzles 140 or water holes are formed in positions, outside the blade grooves 110, of the drill bit body 100;

Movable blade 200: as shown in fig. 9 and 11, the movable blade 200 is mounted in the blade groove 110 formed on the drill bit body 100, the movable blade 200 includes at least one guide block 210 disposed on a side surface, a wedge-shaped T-shaped groove 220 disposed at a middle inner position, and cutting teeth 700 and core teeth 800 disposed on the blade 200, the guide block 210 is movably coupled to the first guide groove 111, so as to stabilize the drill bit and the blade during rock drilling, and at the same time, assist the drill bit to reliably and stably change diameter through the movable blade 200, and the wedge-shaped T-shaped groove 220 is disposed at the middle inner position;

barrel 300: as shown in fig. 1, fig. 2, fig. 5, fig. 6 and fig. 12, one end of the cylinder 300 is provided with a first connector 310 fixedly connected with the first connector 130 of the drill bit body 100, the other end is provided with a second connector 320, at least two sinking grooves 321 for fixing the motor 520 are uniformly arranged on the second connector 320 in circumferential direction, and the cylinder 300 is welded or screwed with the first connector 130 of the drill bit body 100 through the first connector 310.

Male connector 400: as shown in fig. 1, 2, 5, 6 and 13, one end of the male connector 400 is provided with a male cone thread 410 connected with a drill tool such as a drill collar or a drill rod, and the other end is provided with a second connector 420, and the male connector 400 is welded or screwed with the second connector 320 of the cylinder 300 through the second connector 420.

A motor drive unit: as shown in fig. 6, 7, and 11 to 13, the motor driving unit includes a power supply 510, a motor 520, a transmission shaft 530, and a guide 540;

motor 520: as shown in fig. 5, fig. 6, fig. 14, fig. 15 and fig. 16 (a) show the structure, at least two fixing blocks 521 which are matched with the sinking groove 321 on the cylinder 300 to fix the motor driving unit are arranged on the motor 520, an electric connector 522 and an inserting hole 524 are arranged on the motor 520, a fixing block 521 is arranged at one end of the motor 520 close to the rotating shaft 525, the rotating shaft 525 is tightly sleeved with the rotating shaft rubber sleeve 570 to prevent the drilling fluid from entering the motor 520 to damage the interior, an electric connector 522 and an inserting hole 524 which are connected with the power supply 510 are arranged at the tail part of the other end, and a signal channel interface 523 is also arranged on the motor 520 to be connected with a MWD measuring device or a wired drill rod wire to transmit signals so as to realize forward rotation and reverse rotation control of the motor 520, thereby realizing radial expansion of the movable blades 200 to achieve the purpose of variable diameters of drill bits.

A drive shaft 530: as shown in fig. 5, fig. 6, fig. 11, fig. 14, fig. 15 and fig. 17, one end of the transmission shaft 530 is provided with a connection shaft 532 fixedly connected with a rotation shaft 525 of the motor 520, the other end is provided with an external screw thread 531, a guide head 540 is connected with the guide head through a screw pair, one end of the guide head 540 is provided with an internal screw thread 542, the other end of the guide head 540 is at least fixedly connected with a wedge-shaped T-shaped block 541 which is matched with the wedge-shaped T-shaped groove 220 to slide, and a corrugated sealing tube 560 is further provided on the transmission shaft 530 for sealing protection, so as to prevent sediment and the like from entering the screw pair to affect the transmission.

Power supply device 510: as shown in fig. 5, fig. 6, fig. 11, fig. 14, fig. 15 and fig. 16 (b) show that the power supply device 510 is a micro hydraulic generator, a hydraulic impeller 511 is arranged on the power supply device 510 and is used for generating electricity by means of rotation of hydraulic impact force under the action of drilling fluid, and electric energy with continuous proper voltage is provided for the motor 520 through an electric connector 522, and the power supply device 510 is firmly inserted into and installed at the upper part of the motor 520 through an insertion pin 513 and an electric connector 512 respectively with an insertion hole 524 and the electric connector 522. The power supply device 510 is further provided with a buffer protection cover 550 for sealing protection, the buffer protection cover 550 is fastened on a fixed block 521 on the motor 520 through a screw, and the open end of the buffer protection cover 550 can be tightly matched with the motor 520 to prevent drilling fluid from entering and damaging the power supply device 510.

As shown in fig. 1 to 6, a top tooth hole 120 is provided at the top center of the drill body 100 for mounting a top tooth 600, and the top tooth 600 may be a conical tooth, a spherical tooth, a wedge tooth, a spoon tooth, or the like.

As shown in fig. 7 and 8, a strip-shaped water hole 112 is provided on the blade groove 110 near the center of the drill bit body 100, and the effective length of the strip-shaped water hole 112 should be equal to or slightly greater than the maximum moving distance of the movable blade 200 along the radial direction of the drill bit body 100, namely: the moving range S of the movable blade 200 should be within the horizontal projection length of the strip-shaped water hole 112 or within the maximum vertical depth interval of the wedge-shaped T-shaped groove 220, and not be greater than the horizontal projection of the strip-shaped water hole 112 or exceed the maximum vertical depth of the wedge-shaped T-shaped groove 220.

As shown in fig. 1-6, 9 and 18, the movable blade 200 is provided with a plurality of cutting teeth 700, a central tooth 800 is provided on a vertical surface near the drill bit central portion, and the central teeth 800 may be PDC teeth, spherical teeth, spoon teeth, wedge teeth, etc. in the circumferential direction of the drill bit central portion, the central teeth 800 may be arranged on the same plane or in a staggered manner.

In this embodiment, the motor 520 in the motor driving unit is a stepping motor or a servo motor that can be controlled by pulse and direction signals.

In this embodiment, the drill body 100 and the barrel 300 and the male connector 400 may be connected by a straight thread or a tapered thread, a rivet connection, a snap connection, or the like, in addition to the connection method described in the present utility model.

The technical features of all embodiments in the utility model can be freely combined to form the embodiments, and the utility model can be adopted and claimed.

The working state is as follows when in use:

The working principle of the PDC drill bit with the variable diameter driven by the motor is as follows: the movable blade 200 is slidably mounted on the drill bit body 100 and is connected with the wedge-shaped T-shaped groove block of the guide head 540, wherein the guide head 540 is connected with the rotating shaft 525 of the motor 520 through the transmission shaft 530, when the motor 520 receives a ground forward or reverse rotation signal through the signal channel interface 523, the motor 520 can drive the transmission shaft 530 to forward or reverse rotation through forward or reverse rotation, since the transmission shaft 530 and the above parts are axially fixed on the cylinder 300 through the fixing block 521 on the motor 520, and the guide head 540 positioned at the lower part of the transmission shaft 530 is connected with the transmission shaft 530 only through the screw pair, the wedge-shaped T-shaped block 541 on the guide head 540 can slide in the wedge-shaped T-shaped groove 220 on the movable blade 200 and is not fixed by other limit constraints, when the motor 520 rotates forward or backward, the guide head 540 will ascend or descend under the effect of the screw pair, and when the guide head 540 ascends or descends, the guide head 540 can push the movable blade 200 to move in a radial expansion and contraction manner under the matching condition because the wedge-shaped T-shaped groove 220 and the wedge-shaped T-shaped block 541 are matched at the same inclination angle and the angle range is between 10 degrees and 26 degrees, so that the diameter of the PDC drill bit is changed, and the motor 520 is a servo motor or a stepping motor, so that the diameter-changing operation of any multiple diameter-changing values within the maximum diameter-changing range can be realized through control, the problem of drill bit jamming caused by well diameter shrinkage in the drilling process can be solved more automatically through an automatic diameter-changing mode, and the drilling efficiency is improved.

Meanwhile, the top tooth holes for installing the top teeth 600 are formed in the drill bit body 100, the center teeth 800 are arranged on the vertical side of the center part of the drill bit in a staggered manner on the same or different circumferential planes, the danger that the core in the middle of a well hole cannot be timely broken to damage the center part of the drill bit body 100 and impact to the drill bit due to the fact that the core in the middle of the well hole cannot be timely broken due to the fact that the middle of the drill bit is hollow is effectively solved under the combined action of circumferential breaking and top impact crushing of the top teeth 600 and the center teeth 800 (as shown in fig. 18), the drilling efficiency is improved, and the strip-shaped water holes 112 can effectively prevent rock fragments from accumulating in the blade grooves 110 under the action of higher-pressure drilling fluid after the drill bit is changed, so that the telescopic movement of the movable blades 200 is influenced, and the drilling risk is reduced.

Description of embodiments in the present utility model:

1. the wedge angle of the wedge-shaped T-shaped block 541 and the wedge-shaped T-shaped slot 220 means that the included angle formed by the inclined surfaces of the wedge-shaped T-shaped block 541 and the wedge-shaped T-shaped slot 220 with respect to the center line of the bit body 100 after the wedge-shaped T-shaped block 541 and the wedge-shaped T-shaped slot 220 are assembled is the wedge angle of the wedge-shaped T-shaped block 541 and the wedge-shaped T-shaped slot 220.

2. Full-size drilling refers to the drill bit drilling at the same diameter as the borehole.

3. In embodiments 1 to 3, the bit direction is vertically upward as shown in fig. 1, 2, 5 and 6, that is, the bit is vertically upward, and the bit body 100 is positioned uppermost, and thus, the operation states in embodiments 1 to 3 are described in the above directions. In actual drilling operations, the bit direction is exactly opposite to that of fig. 1 and 3, i.e., the bit is vertically downward, and the bit body 100 is positioned at the lowermost position, so that the setting direction of the reducing mechanism is also inverted.

In addition, the motor 520 rotates forward and backward to drive the guide head 540 to move up and down, and the guide head 540 drives the wedge-shaped T-shaped block 541 to slide in the wedge-shaped T-shaped slot 220, which can be switched according to the requirement in actual drilling, so that the utility model is applicable.

The foregoing description is only a preferred embodiment of the present utility model, and is not intended to limit the present utility model in any way, and any simple modification, equivalent variation, etc. of the above embodiment according to the technical matter of the present utility model fall within the scope of the present utility model.

Claims

1. The utility model provides a variable diameter PDC drill bit, its characterized in that, including setting gradually and the drill bit body (100) that the intercommunication formed cylindrical cavity, barrel (300) and pin joint (400) and reducing mechanism, drill bit body (100) establish movable blade (200) and be used for installing blade groove (110) of movable blade (200), be equipped with in blade groove (110) and inject second guide way (113) of movable blade (200) flexible direction, second guide way (113) are followed drill bit body (100) radially run through to its inside, be equipped with on blade groove (110) inner wall with drill bit body (100) radial parallel's first guide way (111), reducing mechanism including locating wedge T type groove (220) of movable blade (200) inboard, locate wedge T type piece (541) that the wedge angle equals and fixed set up in cylindrical cavity, be equipped with on wedge T type groove (220) outer wall with first guide way (210) and go into through first guide way (540) axial direction motor drive unit (541) and the drill bit body (100) are passed through in setting up.

2. The variable diameter PDC bit of claim 1 wherein the wedge angle range is between 10 ° and 26 °.

3. The variable diameter PDC drill bit of claim 1 wherein the motor drive unit comprises a motor (520) fixedly disposed at the lower end of the cylindrical cavity, a transmission shaft (530) disposed on the axis of the drill bit body (100), and a guide head (540), the motor (520) being connected to a connecting shaft (532) at one end of the transmission shaft (530) through a rotation shaft (525), the guide head (540) being connected to the other end of the transmission shaft (530) through a screw pair and axially moving with the transmission shaft (530) in the drill bit body (100).

4. A variable diameter PDC drill bit according to claim 3, characterized in that at least two sinking grooves (321) are uniformly arranged at the connection end of the cylinder body (300) and the male connector (400) in the circumferential direction, and a fixing block (521) matched with the sinking grooves (321) is arranged on the motor (520).

5. A variable diameter PDC bit according to claim 3 characterized in that the motor (520) is further provided with a signal channel interface (523) for receiving a control signal of the motor (520).

6. A variable diameter PDC bit according to claim 3, characterized in that the motor drive unit further comprises power supply means of the motor (520).

7. The variable diameter PDC bit of claim 6 wherein the power supply is a miniature hydro-generator (510) provided with a hydraulic impeller (511), the motor (520) being connected to and energized by an electrical connector (522) provided on the miniature hydro-generator (510).

8. The variable diameter PDC bit of claim 7 wherein the motor (520) is provided with a shaft gum cover (570) to prevent drilling fluid ingress, a bellows seal tube (560) is external to the screw pair, and a buffer boot (550) to prevent drilling fluid ingress is external to the miniature hydraulic generator (510).

9. The variable diameter PDC bit of any of claims 1-8 wherein a top tooth (600) is provided on top of the bit body (100) and a center tooth (800) is provided inboard of the top of the movable blade (200).

10. The variable diameter PDC bit of claim 9 wherein the top of the blade grooves (110) are provided with strip-shaped water holes (112) and a nozzle (140) is provided between the blade grooves (110) at a center of the top of the bit body (100).