Drilling tool, drilling method and drilling steering method

Abstract

The present invention provides a drilling tool, a drilling method, and a drilling steering method. The drilling tool comprises a drill bit, a downhole motor, a force transmission mechanism, a control device, and a posture measurement device. The downhole motor comprises a stator mechanism and a rotor mechanism, and the drill bit is connected to the lower end of the rotor mechanism. The force transmission mechanism and the posture measurement device are both mounted on the downhole motor. The control device is electrically connected to the posture measurement device and can control the force transmission mechanism to move radially based on a predetermined steering direction and posture information measured by the posture measurement device. This invention solves the technical problem of difficulty in achieving steering in small-hole drilling.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploitation, and in particular to a drilling tool, a drilling method and a drilling steering method. Background Art

[0002] During slimhole drilling, the drill bit rotates at a high speed, offering advantages in efficiency and environmental friendliness. To achieve steering during drilling, an offset guide mechanism is installed at the lower end of the drill string. By controlling the offset guide mechanism, the drill bit steers in a predetermined direction. However, due to the limited space available in slimholes, the offset guide mechanism typically requires a relatively large area, making it difficult to achieve steering in these situations. Summary of the Invention

[0003] The purpose of the present invention is to provide a drilling tool, a drilling method and a drilling steering method to solve the technical problem that it is difficult to achieve steering in small hole drilling.

[0004] The above-mentioned purpose of the present invention can be achieved by adopting the following technical solutions:

[0005] The present invention provides a drilling tool, comprising: a drill bit, a downhole motor, a force transmission mechanism, a control device, and a posture measurement device, wherein the downhole motor comprises a stator mechanism and a rotor mechanism, and the drill bit is connected to the lower end of the rotor mechanism;

[0006] The force transmission mechanism and the posture measurement device are both installed on the downhole motor. The control device is electrically connected to the posture measurement device. The control device can control the force transmission mechanism to move radially according to a predetermined steering direction and the posture information measured by the posture measurement device.

[0007] In a preferred embodiment, the drilling tool includes a guide hydraulic cylinder and a control mechanism. The drilling tool is provided with a flow channel for supplying driving fluid to the guide hydraulic cylinder. The control mechanism can regulate the flow of the driving fluid in the flow channel under the control of the control device; the guide hydraulic cylinder is connected to the force transmission mechanism and can drive the force transmission mechanism to move radially.

[0008] In a preferred embodiment, the control mechanism is disposed above the rotor mechanism, or the control mechanism is disposed inside the rotor mechanism.

[0009] In a preferred embodiment, the stator mechanism includes a stator, and the control mechanism is installed above the stator.

[0010] In a preferred embodiment, the stator mechanism is used to be connected to a drill string and can rotate driven by the drill string; the force transmission mechanism and the posture measurement device are both installed on the stator mechanism.

[0011] In a preferred embodiment, the force transmission mechanism includes a sliding inclined surface; the guide hydraulic cylinder can perform telescopic movement along the longitudinal direction of the drilling tool and drive the force transmission mechanism to perform radial movement under the action of the sliding inclined surface.

[0012] In a preferred embodiment, the flow channel is provided on the cylindrical wall of the downhole motor stator mechanism.

[0013] In a preferred embodiment, the guide hydraulic cylinder is fixed to the rotor mechanism; the rotor mechanism includes a rotor, and the flow channel includes a first flow channel provided on the rotor.

[0014] In a preferred embodiment, the control mechanism is installed above the stator, and the upper end of the rotor is connected to the control mechanism via a flexible tube.

[0015] In a preferred embodiment, the rotor mechanism includes a transmission shaft, the drill bit is connected to the rotor via the transmission shaft, and the flow channel includes a second flow channel provided on the transmission shaft and communicating with the first flow channel.

[0016] In a preferred embodiment, the rotor mechanism includes a flexible shaft, the transmission shaft is connected to the rotor through the flexible shaft, the flow channel includes a third flow channel arranged on the flexible shaft, and the first flow channel, the third flow channel, the second flow channel and the guide hydraulic cylinder are connected in sequence.

[0017] In a preferred embodiment, a transfer bearing is provided between the guide hydraulic cylinder and the force transmission mechanism.

[0018] In a preferred embodiment, the control mechanism includes an electrically driven actuator, a valve seat and a control valve core, wherein the control valve core is connected to the electrically driven actuator, and the control valve core moves relative to the valve seat under the drive of the electrically driven actuator, and is used to control the flow of the drilling circulating fluid in the drill string water hole and the flow channel.

[0019] In a preferred embodiment, the downhole motor is a screw motor, a downhole turbine motor or a downhole electric motor.

[0020] In a preferred embodiment, the stator mechanism includes a stator and a motor housing connected to the lower end of the stator; the rotor mechanism includes a rotor, a flexible shaft and a transmission shaft connected in sequence from top to bottom, and the motor housing and the transmission shaft are connected through a bearing assembly.

[0021] In a preferred embodiment, the control mechanism and the control device are both arranged in the rotor mechanism, and a drainage flow channel is provided in the rotor mechanism. The drainage flow channel is arranged above the control mechanism, the lower end of the drainage flow channel is connected to the control mechanism, and the upper end of the drainage flow channel is connected to the internal flow channel of the drill string above the downhole motor through an inlet hole.

[0022] In a preferred embodiment, the drilling tool further includes a rotary power transmission device, which includes a rotary power transmission rotor end and a rotary power transmission stator end. The rotary power transmission rotor end is electrically connected to the control device, and the rotary power transmission stator end obtains electrical energy from a power supply through a power supply line.

[0023] The present invention provides a drilling method using the above-mentioned drilling tool, the drilling method comprising:

[0024] The stator mechanism rotates driven by the drill string;

[0025] The drill bit is lowered to a predetermined turning position. When the posture measurement device measures that the force transmission mechanism has rotated to the opposite side of the predetermined turning direction, the control device controls the force transmission mechanism to extend to abut against the well wall to push the drill bit to deflect toward the predetermined turning direction.

[0026] The present invention provides a drilling steering method, comprising: a force transmission mechanism is installed at the lower end of a drilling tool;

[0027] The drill tool is lowered to a predetermined turning position. When the force transmission mechanism rotates to the opposite side of the predetermined turning direction, the force transmission mechanism extends to abut against the well wall to push the drill tool to deflect toward the predetermined turning direction.

[0028] The characteristics and advantages of the present invention are:

[0029] (1) The drill bit can be steered under high-speed composite drilling conditions. The downhole motor increases the speed of the drill bit. The downhole motor rotates with the drill string as a whole, so the friction between the drill string and the well wall is generally in the tangential direction of the drill string, reducing the friction along the drill string axis. This solves the problems of bottom hole drilling power, drilling pressure torque transmission and guidance, and has a good technical effect on deep well drilling and branch well drilling.

[0030] (2) Using a downhole motor to increase the speed near the drill bit, a force transmission mechanism is set at the stator end of the downhole motor. Since the electronic circuit is far away from the drill bit, the influence of vibration on the small-hole rotary guide motor is greatly reduced through the post-control mechanism and control device, thus achieving efficient small-hole steerable drilling.

[0031] (3) The drill bit uses the internal flow channel as a channel for transmitting the driving fluid, which can fully utilize the high-pressure drilling circulating medium above the motor to drive the steering actuator, generating a large guiding force and achieving a good guiding effect;

[0032] (4) The drilling tool can control the guide actuator on the motor housing. The guide actuator only rotates slowly with the motor housing, which greatly reduces the friction between the force transmission mechanism and the well wall and greatly reduces the wear on the guide actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1-Figure 2 A schematic structural diagram of an embodiment of a drilling tool provided by the present invention;

[0035] Figure 3 for Figure 2 A partial enlarged view of point A in the middle;

[0036] Figure 4 for Figure 2 A partial enlarged view of point B in the middle;

[0037] Figure 5 for Figure 4 A partial enlarged view of point C in the middle;

[0038] Figure 6 for Figure 4 A partial enlarged view of point D in the middle;

[0039] Figure 7-Figure 8 A schematic structural diagram of another embodiment of the drilling tool provided by the present invention;

[0040] Figure 9 for Figure 8 A partial enlarged view of point E in the middle;

[0041] Figure 10 for Figure 9 A partial enlarged view of point F in the middle;

[0042] Figure 11-12 A schematic structural diagram of another embodiment of the drilling tool provided by the present invention;

[0043] Figure 13 for Figure 12 A partial enlarged view of point G in the middle;

[0044] Figure 14for Figure 13 A partial enlarged view of the H in the middle;

[0045] Figure 15-16 A schematic structural diagram of another embodiment of the drilling tool provided by the present invention;

[0046] Figure 17 A schematic diagram of the connection of the control device in the drilling tool provided by the present invention;

[0047] Figure 18 This is a connection diagram of the force transmission mechanism in the drilling tool provided by the present invention.

[0048] Description of Figure Numbers:

[0049] 33. Cable; 34. Inlet hole; 35. Drainage channel;

[0050] 1. Drill bit; 31. Control device; 32. Attitude measurement circuit; 36. Rotating power transmission device; 361. Rotating power transmission rotor end; 362. Rotating power transmission stator end; 37. Power supply line;

[0051] 2. Stator; 10. Motor housing; 5. Lower centering bearing; 6. Upper centering bearing;

[0052] 3. Rotor; 4. Flexible shaft; 7. Drive shaft; 8. Bearing assembly; 9. Through flow channel;

[0053] 17, first flow channel; 15, second flow channel; 16, third flow channel; 29, throttle hole;

[0054] 22. Dynamic sealing mechanism; 21. Flexible tube; 23. Flexible tube flow channel;

[0055] 11. Force transmission mechanism; 110. Sliding slope;

[0056] 111. Thrust structure at the power transmission mechanism end; 112. Thrust structure at the piston end; 113. Adapter bearing;

[0057] 120, guide hydraulic cylinder; 12, hydraulic piston; 13, piston cylinder;

[0058] 14. Reset mechanism;

[0059] 250. Control agency;

[0060] 25. Valve seat; 251. Rotary valve stator; 252. Valve seat with throttle hole; 24. Control valve inlet;

[0061] 26. Control valve core; 261. Rotary valve rotor; 262. Valve stem;

[0062] 27. Electric drive actuator; 271. Electric motor; 272. Angle position sensor; 273. Lead screw; 274. Electromagnet;

[0063] 28. Return spring. DETAILED DESCRIPTION

[0064] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0065] Option 1

[0066] The present invention provides a drilling tool, such as Figures 1-14 and Figure 18 As shown, the drilling tool includes: a drill bit 1, a downhole motor, a force transmission mechanism 11, a control device and a posture measurement device. The downhole motor includes a stator mechanism and a rotor mechanism, and the drill bit 1 is connected to the lower end of the rotor mechanism; the force transmission mechanism 11 is installed on the downhole motor; the posture measurement device is installed on the drill bit 1 or the downhole motor, and the control device is electrically connected to the posture measurement device. The control device can control the force transmission mechanism 11 to move radially according to the predetermined steering direction and the posture information measured by the posture measurement device.

[0067] The downhole motor drives the drill bit 1 to rotate for drilling. The force transmission mechanism 11 rotates with the downhole motor, and the attitude measurement device can measure the real-time tool face high edge angle of the force transmission mechanism 11. During the steering process, when the attitude measurement device measures that the force transmission mechanism 11 has rotated to the opposite side of the predetermined steering direction, the control device controls the force transmission mechanism 11 to extend to abut against the well wall to push the drill bit to deflect in the predetermined steering direction. The force transmission mechanism 11 rotates, and by controlling the time of the force transmission mechanism 11 extending, the drill bit can be turned in various directions as needed; and in the drill bit, there is no need to arrange multiple force transmission mechanisms in the circumference to achieve steering in multiple directions. Therefore, the diameter of the drill bit can be relatively small, which is suitable for small wellbores, solving the technical problem of difficulty in achieving guidance in small wellbore drilling.

[0068] The force transmission mechanism 11 and the attitude measurement device can both be installed inside or within 10 meters of the downhole motor. In some embodiments, the stator mechanism is connected to the drill string and can rotate driven by the drill string; the force transmission mechanism 11 and the attitude measurement device are both installed on the stator mechanism. During drilling, the stator mechanism rotates at a relatively low speed driven by the drill string, while the rotor mechanism rotates at a relatively high speed relative to the stator mechanism. These two motions combine, and the drill bit 1 is mounted on the rotor 3, increasing the drill bit 1's rotational speed and enabling composite drilling with the drill bit 1, which offers significant advantages in slim-hole drilling. When steering is required, the extension motion of the force transmission mechanism 11 matches the rotational motion of the stator mechanism, enabling the drill bit 1 to steer in multiple directions under the action of the force transmission mechanism 11, thereby enabling the drill tool to steer in a predetermined direction as needed. On the one hand, the stator mechanism drives the force transmission mechanism 11 to rotate; on the other hand, the low speed of the stator mechanism facilitates control of the extension and retraction motion of the force transmission mechanism 11, ensuring that the extension and retraction motion of the force transmission mechanism 11 matches the rotational motion of the stator mechanism. The attitude measurement device is communicatively connected to the control device. Specifically, the attitude measurement device is located within 30 meters behind the drill bit 1. The attitude measurement device includes an attitude measurement circuit 32, which generally includes an attitude measurement sensor and an attitude calculation circuit. The attitude measurement device can measure the real-time tool face high side angle of the force transmission mechanism 11.

[0069] The force transmission mechanism 11 can move radially under the drive of a hydraulic cylinder or a motor. In some embodiments, the drilling tool includes a guide hydraulic cylinder 120 and a control mechanism 250. The drilling tool is provided with a flow channel for supplying driving fluid to the guide hydraulic cylinder 120. The control mechanism 250 can regulate the flow of the driving fluid in the flow channel under the control of a control device. The guide hydraulic cylinder 120 is connected to the force transmission mechanism 11 and can drive the force transmission mechanism 11 to move radially.

[0070] The control mechanism 250 can control the connectivity between the drilling circulating fluid in the drill string water hole and the flow channel, and the control mechanism 250 can be connected to the upper end of the flow channel. Specifically, it can control the connectivity between the drilling circulating fluid in the drill string water hole and the flow channel, generally to connect the two or cut off the connection between the two. The force transmission mechanism 11 and the guide hydraulic cylinder 120 constitute a guide actuator, and the guide actuator includes at least one guide hydraulic cylinder 120. The guide hydraulic cylinder 120 includes a hydraulic piston 12 and a piston cylinder 13. The driving fluid released by the control mechanism 250 drives the hydraulic piston 12 to move, and further drives the force transmission mechanism 11 to push against the well wall to form a guide force. The force transmission mechanism 11 can be the guide hydraulic cylinder 120 itself, for example, the force transmission mechanism 11 is the piston of the guide hydraulic cylinder 120; it can also be other components that can be driven by the hydraulic cylinder. Preferably, the guide actuator is arranged below the rotor 3.

[0071] like Figure 3As shown, the force transmission mechanism 11 includes a sliding ramp 110; the guide hydraulic cylinder 120 is capable of telescopic movement along the longitudinal direction of the drill string and, under the action of the sliding ramp 110, drives the force transmission mechanism 11 to move radially. The drill string may also include a reset mechanism to assist the hydraulic piston 12 in returning to its original position or to assist in resetting the pushing mechanism. Specifically, the reset mechanism may be an elastic structure, including a spring, a corrugated spring, a disc spring, or a liquid spring, which can assist the hydraulic piston 12 in returning to the dead point of its stroke. When the control mechanism 250 cuts off or obstructs the flow between the water hole and the flow channel in the drill string, the pressure in the flow channel decreases, and the elastic structure can assist the hydraulic piston 12 in returning to the dead point.

[0072] In some embodiments, the guide hydraulic cylinder 120 is fixed to the stator mechanism, and the flow channel can be set in the stator mechanism. Specifically, the stator mechanism includes a stator 2 and a motor housing 10, and the flow channel can be set inside the cylindrical wall of the cylindrical structure formed by the stator 2 and the motor housing 10.

[0073] In some embodiments, the pilot hydraulic cylinder 120 is fixedly connected to the rotor mechanism; the rotor mechanism includes a rotor 3, and the flow channel includes a first flow channel 17 provided on the rotor 3, so that the first flow channel 17 can be arranged by utilizing the space on the rotor 3. The control device 31 is electrically connected to the control mechanism 250 and can drive the control mechanism 250 to control the flow rate and pressure of the drilling circulating medium in the first flow channel 17, thereby driving the force transmission mechanism 11 to perform the steering action. Specifically, the control device includes a control circuit, which implements the control function.

[0074] The force transmission mechanism 11 is driven by the guide hydraulic cylinder 120 to perform radial expansion and contraction motion. The force transmission mechanism 11 is fixed to the stator mechanism, and the guide hydraulic cylinder 120 is fixed to the rotor mechanism. Then, there will be relative rotation between the guide hydraulic cylinder 120 and the force transmission mechanism 11. Figure 3 In the drilling tool shown, the guide hydraulic cylinder 120 moves axially through the sliding inclined surface 110, which can drive the power transmission mechanism 11 to move radially. The radial direction is all directions from the axis to the outside. Through this structure, the guide hydraulic cylinder 120 is easily connected and transmitted to the power transmission mechanism 11.

[0075] The driving fluid can be mud in the water hole of the drill string. The first flow channel 17 is connected to the water hole in the drill string above the rotor 3, and is used to allow the high-pressure drilling circulating medium above the rotor 3 to flow in to transfer the control fluid required to drive the steering actuator. The control mechanism 250 can be set inside the first flow channel 17 or above the first flow channel 17. The control mechanism 250 is used to control the opening and closing of the first flow channel 17. Figure 2As shown, the upper end of first flow channel 17 is connected to a control mechanism 250, which is used to control the flow of drilling circulating medium in the drill string water hole to first flow channel 17. The hydraulic pistons 12 contained in a group of pilot hydraulic cylinders 120 in the pilot actuator move synchronously under the drive of the high-pressure drilling circulating medium in the first flow channel 17.

[0076] The high-pressure energy contained in the high-pressure drilling circulating medium is the high-pressure energy caused by the pressure differential inside and outside the drill string. This high pressure is the throttling pressure differential of approximately 1-10 MPa generated by the downhole motor throttling. When the drilling circulating medium flows through the downhole motor and drill bit 1, a pressure drop is generated, typically ranging from 1-15 MPa. Therefore, the flow channel guides the high-pressure drilling circulating medium within the drill string water hole to the steering actuator, which uses the drilling hydraulic pressure differential inside and outside the drill string to drive the steering actuator to perform the steering action. The control mechanism 250 is located above the downhole motor, which facilitates the miniaturization of the drilling tool and is suitable for use in small wellbores.

[0077] In one embodiment, the stator mechanism includes a stator 2, such as Figure 2 As shown, the control mechanism 250 is installed above the stator 2. Specifically, the control mechanism 250 is fixedly arranged inside the motor housing 10. The control mechanism 250 is arranged above the rotor 3, as shown in FIG. Figure 2 、 Figure 4 and Figure 6 As shown, the upper end of the rotor 3 is connected to the control mechanism 250 through a flexible tube 21. Figures 1-14 As shown, the flexible tube 21 is provided with a flexible tube flow channel 23, and the control fluid guided by the control mechanism 250 enters the first flow channel 17 through the flexible tube flow channel 23. The flexible tube 21 is in sealed communication with the rotor 3 through the dynamic sealing mechanism 22.

[0078] In one embodiment, if Figures 1-14 As shown, the control mechanism 250 is arranged above the rotor mechanism; or, as Figure 15-16 As shown, the control mechanism 250 is disposed inside the rotor mechanism.

[0079] like Figure 1-Figure 3 As shown, the rotor mechanism includes a transmission shaft 7, through which the drill bit 1 is connected to the rotor 3. The flow channel includes a second flow channel 15 provided on the transmission shaft 7 and connected to the first flow channel 17. The second flow channel 15 is connected to the first flow channel 17 and the guide actuator respectively. The first flow channel 17 is connected to the guide actuator through the second flow channel 15, and is used to drive the guide actuator. Specifically, the second flow channel 15 is provided inside the transmission shaft 7. Figure 1-Figure 2As shown, the rotor mechanism includes a flexible shaft 4, through which the transmission shaft 7 is connected to the rotor 3. The flow channel includes a third flow channel 16 provided on the flexible shaft 4. The first flow channel 17, the third flow channel 16, the second flow channel 15, and the guide hydraulic cylinder 120 are sequentially connected to transmit the driving fluid released by the control mechanism 250. The transmission shaft 7, the flexible shaft 4, and the rotor 3 are sequentially connected from bottom to top to transmit rotational power to the drill bit 1. Preferably, the flexible shaft 4 is made of titanium alloy, and the third flow channel 16 is provided inside the flexible shaft 4. Figure 12 As shown, the transmission shaft 7 is provided with a through flow channel 9, and the drilling fluid in the drill string flows into the drill bit through the through flow channel 9, and then is discharged into the wellbore through the drill bit.

[0080] like Figure 3 As shown, an adapter bearing is provided between the guide hydraulic cylinder 120 and the force transmission mechanism 11. The guide hydraulic cylinder 120 includes a hydraulic piston 12 and a piston cylinder 13. The piston cylinder 13 is nested outside the transmission shaft 7, and the hydraulic piston 12 is slidably fitted within the piston cylinder 13. The hydraulic piston 12 is connected to the force transmission mechanism 11 via an adapter bearing 113. The driving fluid released by the control mechanism 250 drives the hydraulic piston 12, which in turn drives the force transmission mechanism 11 against the wellbore wall via the adapter bearing 113, generating a guide force. Specifically, the adapter bearing 113 includes a piston-end thrust structure 112 and a force transmission mechanism-end thrust structure 111.

[0081] Control mechanism 250 can be any type of electrically controlled valve capable of controlling the connectivity between the drilling circulating fluid in the drill string water hole and the first flow channel 17. Control mechanism 250 includes an electrically driven actuator 27, a valve seat 25, and a control valve core 26. Control valve core 26 is connected to electrically driven actuator 27 and moves relative to valve seat 25 under the drive of electrically driven actuator 27 to control the connectivity between the drilling circulating fluid in the drill string water hole and the flow channel.

[0082] In one embodiment, the electrically controlled valve is an electrically operated rotary valve, such as Figure 1 、 Figure 2 、 Figure 4 and Figure 5 As shown, the electric actuator 27 is an electric motor 271, the control valve core 26 is a rotary valve rotor 261, and the valve seat 25 is a rotary valve stator 251. The rotary valve rotor 261 rotates relative to the rotary valve stator 251 under the drive of the electric motor 271 to realize the connection and disconnection of the drilling circulating fluid and the flow channel in the drill string water hole.

[0083] In another embodiment, the electrically controlled valve is an electrically operated reversing valve, such as Figure 7-10As shown, the electric actuator 27 is a linear drive motor, which is a linear motor or a combination of an electric motor 271 and a lead screw 273. The control valve core 26 is a valve stem 262, and the valve seat 25 is a valve seat 252 with a throttle hole. Driven by the linear drive motor, the valve stem 262 moves linearly relative to the valve seat 252 with a throttle hole of the rotary valve stator 251, and can periodically change the throttling area of ​​the throttle hole to achieve the connection and disconnection of the drilling circulating fluid and the flow channel in the water hole of the drill string.

[0084] Figure 1 and Figure 7 In the drilling tool shown, the motor 271 includes an angular position sensor 272, which is a Hall sensor or a rotary transformer.

[0085] In another embodiment, the electrically controlled valve is a solenoid valve, such as Figure 11-14 As shown, the electrically driven actuator 27 is an electromagnet 274, the control valve is a valve stem 262, and the valve seat 25 is a valve seat 252 with a throttle hole. Driven by the electromagnet 274, the valve stem 262 moves linearly relative to the valve seat 252 with a throttle hole of the rotary valve stator 251, and can periodically change the throttling area of ​​the throttle hole to achieve the connection and disconnection of the drilling circulating fluid and the flow channel in the drill string water hole.

[0086] The downhole motor can be a screw motor, a downhole turbine motor or a downhole electric motor. Figure 2 As shown, the stator mechanism comprises a stator 2 and a motor housing 10 connected to the lower end of the stator 2. The rotor mechanism comprises a rotor 3, a flexible shaft 4, and a drive shaft 7, connected in descending order. The motor housing 10 and the drive shaft 7 are connected via a bearing assembly 8. A force transmission mechanism 11 is fixedly connected to the motor housing 10 or the stator 2. This mechanism is used to transmit thrust to the wellbore wall or to drive the drill bit 1 to oscillate, thereby changing the wellbore trajectory. The motor housing 10 and stator 2 can be integrally molded or manufactured separately.

[0087] like Figure 7-14 As shown, the drilling tool is provided with a control valve inlet 24, through which high-pressure fluid flows into the upper portion of the valve seat 25. When the electromagnet is engaged, the valve stem is lifted by the electromagnet, and the high-pressure fluid flows through the valve seat into the control flow channel. Figures 11-16 As shown, the control mechanism 250 includes a return spring 28. When the electromagnet is in the non-attractive state, the return spring 28 helps the valve stem to return to its original position. The first flow channel 17, the third flow channel 16, and the second flow channel 15 constitute the control flow channel. Figures 7-16 As shown, the drilling tool is provided with a throttle hole 29 connected to the control flow channel, which is used to remove the fluid in the control flow channel. When the valve stem is lifted by the electromagnet, the flow rate flowing into the control flow channel through the valve seat is greater than the flow rate of the fluid discharged from the throttle hole, so the control flow channel can drive the guide hydraulic cylinder to move. Figures 1-16As shown, the drilling tool includes a lower centering bearing 5 and an upper centering bearing 6. Figure 16 As shown, both the control mechanism 250 and the control device 31 are disposed within the rotor 3. A drainage channel 35 is provided within the rotor 3 and is positioned above the control mechanism 250. The lower end of the drainage channel 35 communicates with the control mechanism 250, while the upper end of the drainage channel 35 communicates with the internal flow channel of the drill string above the downhole motor via an inlet hole 34. The control device 31 and the control mechanism 250 are electrically connected via a cable 33.

[0088] like Figure 17 As shown, the drilling tool includes a rotary power transmission device 36, which includes a rotary power transmission rotor end 361 and a rotary power transmission stator end 362. The rotary power transmission rotor end 361 is electrically connected to the control device 31, and the rotary power transmission stator end 362 obtains electrical energy from a power supply through a power supply line 37. The power supply can be a downhole turbine generator or a battery cartridge, or a power supply at the wellhead.

[0089] This drilling tool can be used in small wells with a diameter of less than 8.5 inches. Especially for small wells within 6 inches, this drilling tool has great advantages:

[0090] (1) In order to solve the problem of difficulty in transmitting drilling pressure torque during drilling, the downhole motor is generally used to increase the rotation speed to overcome it. However, if the rotary steering system is directly connected to the bottom of the motor rotor, the high rotation speed of the motor rotor will cause the rotary steering system to fail. If the steering is achieved by setting a pushing device on the motor housing, the motor housing cannot rotate during drilling, which will cause serious drilling pressure to appear, and the position angle of the pushing device cannot be adjusted downhole, resulting in poor steering accuracy. In order to solve the above problems, the drilling tool can achieve steering under high-speed composite drilling conditions. The downhole motor increases the rotation speed of the drill bit 1, and the downhole motor rotates with the drill string as a whole. The direction of the friction between the drill string and the well wall is roughly the tangent direction of the drill string, which reduces the friction along the axis of the drill string, solves the problems of bottom hole drilling power, drilling pressure torque transmission and steering, and can achieve good technical effects on deep well drilling and branch well drilling.

[0091] (2) There is no applicable dynamic offset steering mechanism in small-hole drilling. The diameter of the static offset steering mechanism is too large, and the space in the small-hole is limited. The drilling tool uses a downhole motor to increase the speed near the drill bit 1. A force transmission mechanism 11 is set at the stator end of the downhole motor. Since the electronic circuit is far away from the drill bit 1, the influence of vibration on the small-hole rotary guide motor is greatly reduced through the post-control mechanism 250 and the control device, thereby achieving efficient small-hole directional drilling.

[0092] (3) During the drilling process, the drilling circulating medium drives the motor rotor 3 to move relative to the motor stator 2, generating a throttling pressure difference of 1-10 MPa between the upper and lower parts of the motor rotor 3. The drill string uses the internal flow channel as a channel for transmitting the driving fluid, and can fully utilize the high-pressure drilling circulating medium above the downhole motor to drive the steering actuator, thereby generating a large steering force and achieving a good steering effect.

[0093] (4) During the composite drilling process, the motor housing 10 rotates at a relatively low speed of 30-120 rpm along with the drill string, while the drill bit 1 can eventually reach 180-600 rpm driven by the downhole motor. The drilling tool can control the guide actuator on the motor housing 10, and the guide actuator only rotates slowly along with the motor housing 10, which greatly reduces the friction between the force transmission mechanism 11 and the well wall, and will greatly reduce the wear on the guide actuator.

[0094] Option 2

[0095] The present invention provides a drilling method using the above-mentioned drilling tool, which includes: the stator mechanism rotates under the drive of the drill string; the drilling tool is lowered to a predetermined turning position, and when the attitude measurement device detects that the force transmission mechanism 11 rotates to the opposite side of the predetermined turning direction along with the downhole motor, the control device controls the force transmission mechanism 11 to extend to abut against the well wall to push the drilling tool to deflect in the predetermined turning direction.

[0096] In this drilling method, the stator mechanism rotates at a relatively low speed, driven by the drill string, while the rotor mechanism rotates at a relatively high speed relative to the stator mechanism. These two motions combine, and the drill bit 1 is mounted on the rotor 3, achieving composite drilling with the drill bit 1. This increases the drill bit 1's rotational speed, offering significant advantages in drilling small holes. The force transmission mechanism 11 rotates, and by controlling the timing of its extension, the drill tool can be steered in various directions as needed. This eliminates the need for multiple force transmission mechanisms 11 circumferentially around the drill tool, enabling multiple steering functions. This facilitates reducing the drill tool's diameter and allows for application in small holes, resolving the technical issue of difficult steering in small hole drilling.

[0097] Option 3

[0098] The present invention provides a drilling steering method, comprising: a force transmission mechanism 11 mounted at the lower end of a drill string; the drill string is lowered to a predetermined steering position; when the force transmission mechanism 11 rotates to the side opposite the predetermined steering direction, the force transmission mechanism 11 extends until it abuts against the wellbore wall, thereby pushing the drill string in the predetermined steering direction. The force transmission mechanism 11 rotates, and by controlling the timing of its extension, the drill string can be steered in various directions as needed. This eliminates the need for multiple force transmission mechanisms 11 circumferentially around the drill string to achieve multiple steering directions, facilitates reducing the drill string diameter, and can be applied to small wellbores, resolving the technical problem of difficulty in achieving steering in small wellbore drilling.

[0099] The above descriptions are only several embodiments of the present invention. Those skilled in the art may make various changes or modifications to the embodiments of the present invention based on the contents disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A drilling tool, characterized in that: include: A drill bit, a downhole motor, a force transmission mechanism, a control device, and a posture measurement device. The downhole motor includes a stator mechanism and a rotor mechanism, and the drill bit is connected to the lower end of the rotor mechanism. The force transmission mechanism and the attitude measurement device are both installed on the downhole motor, the control device is electrically connected to the attitude measurement device, and the control device can control the force transmission mechanism to move radially according to a predetermined steering direction and attitude information measured by the attitude measurement device; The drilling tool includes a guide hydraulic cylinder and a control mechanism. The drilling tool is provided with a flow channel for supplying a driving fluid to the guide hydraulic cylinder. The control mechanism is capable of regulating the flow of the driving fluid in the flow channel under the control of the control device. The guide hydraulic cylinder is connected to the force transmission mechanism and is capable of driving the force transmission mechanism to perform radial movement. The stator mechanism is used to be connected to the drill string and can rotate under the drive of the drill string; the force transmission mechanism and the attitude measurement device are both installed on the stator mechanism; The force transmission mechanism includes a sliding inclined surface; the guide hydraulic cylinder can perform telescopic movement along the longitudinal direction of the drilling tool and drive the force transmission mechanism to perform radial movement under the action of the sliding inclined surface; The guide hydraulic cylinder is fixedly connected to the rotor mechanism; the rotor mechanism includes a rotor and a transmission shaft, the drill bit is connected to the rotor via the transmission shaft, and the flow channel includes a first flow channel provided on the rotor and a second flow channel provided on the transmission shaft and connected to the first flow channel; The guide hydraulic cylinder includes a hydraulic piston and a piston cylinder. The piston cylinder is nested on the outside of the transmission shaft. The hydraulic piston is slidingly fitted in the piston cylinder. The hydraulic piston is connected to the force transmission mechanism through a switching bearing. The driving fluid released by the control mechanism drives the hydraulic piston through the first flow channel and the second flow channel, and then drives the force transmission mechanism through the switching bearing to push against the well wall to form a guiding force.

2. The drilling tool according to claim 1, characterized in that The control mechanism is arranged above the rotor mechanism, or the control mechanism is arranged inside the rotor mechanism.

3. The drilling tool according to claim 1, characterized in that The stator mechanism includes a stator, and the control mechanism is installed above the stator.

4. The drilling tool according to any one of claims 1 to 3, characterized in that: The flow channel is arranged on the cylindrical wall of the downhole motor stator mechanism.

5. The drilling tool according to claim 1, characterized in that The control mechanism is installed above the stator, and the upper end of the rotor is connected to the control mechanism through a flexible tube.

6. The drilling tool according to claim 1, characterized in that The rotor mechanism includes a flexible shaft, the transmission shaft is connected to the rotor through the flexible shaft, the flow channel includes a third flow channel arranged on the flexible shaft, and the first flow channel, the third flow channel, the second flow channel and the guide hydraulic cylinder are connected in sequence.

7. The drilling tool according to claim 1, characterized in that The control mechanism includes an electrically driven actuator, a valve seat and a control valve core. The control valve core is connected to the electrically driven actuator. The control valve core moves relative to the valve seat under the drive of the electrically driven actuator to control the flow of the drilling circulating fluid in the drill string water hole and the flow channel.

8. The drilling tool according to claim 1, wherein: The downhole motor is a screw motor, a downhole turbine motor or a downhole electric motor.

9. The drilling tool according to claim 8, characterized in that The stator mechanism includes a stator and a motor housing connected to the lower end of the stator; the rotor mechanism includes a rotor, a flexible shaft and a transmission shaft connected in sequence from top to bottom, and the motor housing and the transmission shaft are connected through a bearing assembly.

10. The drilling tool according to claim 1, wherein The control mechanism and the control device are both arranged in the rotor mechanism. A drainage flow channel is provided in the rotor mechanism. The drainage flow channel is arranged above the control mechanism. The lower end of the drainage flow channel is connected to the control mechanism, and the upper end of the drainage flow channel is connected to the internal flow channel of the drill string above the downhole motor through an inlet hole.

11. The drilling tool according to claim 1, wherein The drilling tool further includes a rotary power transmission device, which includes a rotary power transmission rotor end and a rotary power transmission stator end. The rotary power transmission rotor end is electrically connected to the control device, and the rotary power transmission stator end obtains electrical energy from a power supply through a power supply line.

12. A drilling method, characterized in that: Using the drilling tool according to any one of claims 1 to 11, the drilling method comprises: The stator mechanism rotates driven by the drill string; The drill bit is lowered to a predetermined turning position. When the posture measurement device measures that the force transmission mechanism has rotated to the opposite side of the predetermined turning direction, the control device controls the force transmission mechanism to extend to abut against the well wall to push the drill bit to deflect toward the predetermined turning direction.

13. A drilling steering method, using the drilling tool according to any one of claims 1 to 11, characterized in that: include: The force transmission mechanism is installed at the lower end of the drilling tool; The drill tool is lowered to a predetermined turning position. When the force transmission mechanism rotates to the opposite side of the predetermined turning direction, the force transmission mechanism extends to abut against the well wall to push the drill tool to deflect toward the predetermined turning direction.

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