Short radius drilling tool

Abstract

The present invention provides a short-radius drilling tool, which includes a steering drilling sub, a drive drill string, and a drive control sub. The steering drilling sub includes a steering sub and a drill bit. The steering sub includes a load-bearing body, on which a deflection guiding mechanism and an electric drive actuator are provided. The drill bit is connected to the load-bearing body, and the deflection guiding mechanism can drive the drill bit to deflect in a preset direction. The drive drill string includes a plurality of load-bearing subs connected in sequence from top to bottom. The lowermost load-bearing sub is connected to the load-bearing body, and adjacent load-bearing subs and between the load-bearing sub and the load-bearing body are all hinged through a weight-on-bit torque deflection transmission mechanism. The drive control sub is provided with an electric drive actuator drive control circuit, and the electric drive actuator drive control circuit is electrically connected to the electric drive actuator through a jumper line. The present invention can achieve a short build-up rate, effectively shorten the length of the steering sub, and thus it is easier to achieve the directional drilling function in a high-curvature wellbore.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling, and particularly to a short-radius drilling tool. Background Art

[0002] The development of many oil and gas reservoirs or solid mineral deposits that require fluidized mining requires extensive use of drilling technology, and even horizontal well drilling technology. Since the existing directional drilling technology cannot achieve short-radius turning, it is difficult to develop ultra-thin reservoirs; or it is difficult to build an inclination in the caprock but a large-curvature turning is required after entering the reservoir; or to achieve branched drilling to the greatest extent possible; or to achieve a large-angle turn in the shallow formation, or to drill a branched well in an existing wellbore to utilize the reserves beside the well. In the prior art, the reserves beside the well are usually utilized by the method of drilling a branched well with a positive displacement motor with a bent sub. Existing data shows that the existing positive displacement motor directional drilling technology and other directional drilling technologies cannot exceed a build rate of 15° / 30 m.

[0003] In summary, when the wellbore curvature is too large, it cannot be achieved by the existing directional well technology with controllable trajectory; when the wellbore curvature is too small, the build section is too long, and a large amount of ineffective footage will be generated in the well section in the turning state, resulting in poor economic efficiency and increasing the operation difficulty of the construction well section. Summary of the Invention

[0004] The purpose of the present invention is to provide a short-radius drilling tool with a short guiding structure that can achieve short- to ultra-short-radius wellbore directional drilling or directional drilling of its extended well section through a short- to ultra-short-radius wellbore.

[0005] To achieve the above purpose, the present invention provides a short-radius drilling tool, which includes:

[0006] A guiding drilling sub, which includes a drill bit and a guiding sub. The guiding sub includes a bearing body, a deflection guiding mechanism and an electric drive actuator are arranged on the bearing body, the drill bit is connected to the lower end of the bearing body, and the deflection guiding mechanism can drive the drill bit to deflect in a preset direction;

[0007] A driving drill string, which includes a plurality of bearing subs connected in sequence from top to bottom. The bearing sub at the lowest position is connected to the bearing body, and adjacent two bearing subs and between the bearing sub and the bearing body are articulated through a drill pressure and torque deflection transmission mechanism;

[0008] The drive control sub-section is provided with an electric drive actuator drive control circuit, which is electrically connected to the electric drive actuator through a jumper line. The drive control sub-section is connected between the steering drilling sub-section and the drive drill string, or the drive control sub-section is connected at any position in the drive drill string, or the drive control sub-section is connected to the upper end of the drive drill string.

[0009] The short-radius drilling tool as described above, wherein the deflection steering mechanism includes at least three groups of drive hydraulic cylinders arranged at intervals along the circumference of the load-bearing body. The drive hydraulic cylinder includes a piston cylinder connected to the barrel wall of the load-bearing body and a drive piston arranged in the piston cylinder. The drive piston can abut against the wellbore wall, and the drill bit is deflected in a preset direction by the telescopic movement of the drive piston.

[0010] The short-radius drilling tool as described above, wherein the electric drive actuator drive control circuit at least includes a switch tube carrier circuit board arranged in a ring shape and a switch tube driver carrier circuit board arranged in a ring shape. Switch tubes are provided on the switch tube carrier circuit board, and switch tube drivers are provided on the switch tube driver carrier circuit board. The switch tubes are electrically connected to the switch tube drivers.

[0011] The short-radius drilling tool as described above, wherein the short-radius drilling tool further includes a strapdown attitude measurement module and a steering control circuit. The strapdown attitude measurement module is fixedly arranged in the short-radius drilling tool. The strapdown attitude measurement module can measure the well inclination angle and / or the gravity tool face angle and / or the magnetic tool face angle of the short-radius controllable trajectory drilling tool underground. The steering control circuit is electrically connected to the strapdown attitude measurement module and the electric drive actuator drive control circuit. The steering control circuit can control the electric drive actuator to execute command actions according to the detection data of the strapdown attitude measurement module.

[0012] The short-radius drilling tool as described above, wherein a transmission lever is coaxially connected to the upper end of the drill bit. The transmission lever is connected to the lower part of the load-bearing body through a controllable universal joint, and there is a movable gap between the transmission lever and the load-bearing body. The deflection steering mechanism is arranged in the movable gap and above the controllable universal joint. The drive piston can abut against the wellbore wall through the transmission lever. The telescopic movement of the drive piston can drive the transmission lever to rotate around the center of the controllable universal joint, and the rotation of the transmission lever can drive the drill bit to deflect in a preset direction.

[0013] The short-radius drilling tool as described above, wherein the drive hydraulic cylinder is arranged below the weight-on-bit torque deflection transmission mechanism connected to the load-bearing body;

[0014] The electric drive actuator includes a rotary valve and a drive motor. A through-flow channel is provided on the bearing body. The rotary valve can cyclically connect the through-flow channel with the drive hydraulic cylinder. The drive motor is electrically connected to the drive control circuit of the electric drive actuator.

[0015] The short-radius drilling tool as described above, wherein the rotary valve includes a rotary valve rotor and a rotary valve stator. The rotary valve stator is fixedly connected to the bearing body. The rotary valve stator is provided with a plurality of valve positions respectively corresponding to the drive hydraulic cylinders one by one. The drive motor includes a drive motor rotor and a drive motor stator. The drive motor stator is fixedly connected to the bearing body. The rotary valve rotor is mutually coupled with the drive motor rotor. The drive motor rotor can drive the rotary valve rotor to rotate relative to the rotary valve stator.

[0016] The short-radius drilling tool as described above, wherein a through-flow channel is provided on the bearing body. The electric drive actuator includes a plurality of solenoid valves respectively corresponding to the drive hydraulic cylinders one by one. Each solenoid valve is electrically connected to the drive control circuit of the electric drive actuator. The solenoid valve has a first passage and a second passage. The first passage is connected to the drive hydraulic cylinder. The second passage is connected to the through-flow channel. The solenoid valve can cyclically connect the through-flow channel with the drive hydraulic cylinder.

[0017] The short-radius drilling tool as described above, wherein the steering control circuit is fixedly arranged inside the drive control sub-section, and the steering control circuit is electrically connected to the drive control circuit of the electric drive actuator inside the drive control sub-section.

[0018] The short-radius drilling tool as described above, wherein the steering control circuit is a steering control circuit manufactured by using thick film circuit technology.

[0019] The short-radius drilling tool as described above, wherein the short-radius drilling tool further includes a power supply sub-section. The power supply sub-section is connected in series at any position in the drive drill string, or the power supply sub-section is connected to the upper end of the drive drill string.

[0020] The short-radius drilling tool as described above, wherein the strap-down attitude measurement module is fixedly connected to the bearing body. The strap-down attitude measurement module includes at least one accelerometer. The accelerometer can measure the well inclination angle.

[0021] The short-radius drilling tool as described above, wherein the strap-down attitude measurement module further includes at least one magnetometer. The magnetometer can measure the azimuth angle. The bearing body is a bearing body made of non-magnetic material to avoid magnetic interference.

[0022] The short-radius drilling tool as described above, wherein the strapdown attitude measurement module is a strapdown attitude measurement module manufactured by using a thick-film circuit process

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] For the short-radius drilling tool of the present invention, by providing a deflection guiding mechanism, the deflection guiding mechanism can drive the drill bit to deflect in a preset direction under the condition of rotation so as to change the wellbore trajectory, thereby realizing short- to ultra-short-radius directional drilling or directional drilling for the extended well section through the short- to ultra-short-radius well section; by arranging the drive control circuit of the electric drive actuator, which contains a large number of power devices and requires a heat dissipation space, in the drive control sub-joint behind the carrier body, only the deflection guiding mechanism and the electric drive actuator are retained in the guiding sub-joint, thereby effectively shortening the length of the guiding sub-joint, and further making it easier to realize the directional function in a high-curvature wellbore.

[0025] The present invention selects an electric drive actuator to distribute the drilling circulating medium in the through-flow channel for the drive hydraulic cylinder so as to realize guiding in a specific direction, which can save the energy required for the guiding process to the greatest extent and plays a crucial role in reducing the volume of the mechanical structure and the circuit.

[0026] The strapdown attitude measurement module can realize the attitude measurement of the short-radius drilling tool without relying on an inertial platform, eliminating a large amount of space occupied by the inertial platform and the potential hazards. It helps to miniaturize the carrier body or the carrier sub-joint of the short-radius drilling tool.

[0027] The advantage of arranging both the guiding control circuit and the drive control circuit of the electric drive actuator inside the drive control sub-joint of the electric drive actuator is that the guiding control circuit can more quickly and agilely control the switch tube driver through a PWM signal, and further drive the switch tube through the switch tube driver to realize the control of the electric drive actuator, greatly reducing the interference that may occur in the control link. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention. Among them:

[0029] Figure 1 is the first structural schematic diagram of the short-radius drilling tool of the present invention;

[0030] Figure 2 is the second structural schematic diagram of the short-radius drilling tool of the present invention;

[0031] Figure 3 is the third structural schematic diagram of the short-radius drilling tool of the present invention;

[0032] Figure 4Yes Figure 3 Schematic enlarged view of part A in

[0033] Figure 5 Schematic diagram of the short-radius drilling tool of the present invention in the working state;

[0034] Figure 6 Schematic cross-sectional structure view of the drive control sub-joint.

[0035] Explanation of the reference numerals in the drawings:

[0036] 100, guiding drilling sub-joint;

[0037] 110, drill bit; 111, transmission lever; 112, controllable universal joint;

[0038] 120, guiding sub-joint; 121, bearing body; 1211, through-flow channel; 1212, throttling device;

[0039] 130, deflection guiding mechanism; 131, driving hydraulic cylinder; 1311, piston cylinder; 1312, driving piston; 1313, pushing member;

[0040] 140, electric drive actuator; 141, rotary valve; 1411, rotary valve rotor; 1412, rotary valve stator; 142, drive motor; 1421, drive motor rotor; 1422, drive motor stator; 143, solenoid valve; 1431, first passage; 1432, second passage;

[0041] 200, driving drill string;

[0042] 210, bearing sub-joint;

[0043] 220, drill pressure torque deflection transmission mechanism; 221, transmission universal joint; 222, fixed sleeve; 223, flow pipe;

[0044] 230, electric drive actuator drive control circuit; 231, switch tube bearing circuit board; 232, switch tube driver bearing circuit board;

[0045] 240, jumper line;

[0046] 250, guiding control circuit;

[0047] 260, power supply sub-joint;

[0048] 270, strap-down attitude measurement module;

[0049] 280, drive control sub-joint; 281, pressure-bearing body; 282, pressure-bearing sleeve;

[0050] 300, wellbore. Detailed implementation mode

[0051] For a clearer understanding of the technical solution, objective, and effect of the present invention, the specific implementation manner of the present invention will now be described in conjunction with the accompanying drawings. Among them, the use of the adjectival or adverbial modifiers "upper" and "lower", "inner" and "outer" is only for the convenience of relative reference between multiple groups of terms, and does not describe any specific directional limitation on the modified terms. In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0052] It should be noted that the "front" and "rear" described in the text refer to the front and rear along the drilling direction.

[0053] Currently, downhole tools that can provide drilling in a rotating state have rotary steerable technology. Generally, the rotary steering build rate is about 6° / 30 m. The shortest radius directional steering system currently used by Schlumberger can only reach 15° / 30 m, and at most does not exceed 18° / 30 m in small wellbores. However, in the short - ultra - short radius drilling field, the build curvature radius requirement is generally between 10 m and 60 m, and in the ultra - short radius drilling field, the build curvature radius requirement is generally within 10 m. Due to the congenital inability of the currently used rotary steering system to be bent, it is almost impossible to meet the actual needs of short - radius drilling, and it is impossible to achieve short - ultra - short radius directional drilling with a turning radius within 60 m under rotating drilling conditions. Other related products in the prior art also all have the problem that they cannot achieve the function of wellbore trajectory control under rotating drilling conditions, resulting in serious drag - drilling pressure problems.

[0054] To solve the above problems, as Figure 1 、 Figure 2 、 Figure 3 and Figure 5 shown, the present invention provides a short - radius drilling tool that can achieve short - ultra - short radius wellbore 300 drilling and / or complete the drilling of its extended wellbore 300 through the short - ultra - short radius wellbore 300. The short - radius drilling tool includes a steering drilling sub - section 100, a drive drill string 200, and a drive control sub - section 280, wherein:

[0055] The steerable drilling sub 100 includes a steering sub 120 and a drill bit 110. The steering sub 120 includes a load-bearing body 121 which is cylindrical. The length of the load-bearing body 121 is less than 1.5 meters to adapt to the curvature of the wellbore 300 of the ultra-short radius branch well. A deflection steering mechanism 130 and an electric drive actuator 140 for performing the steering function are provided on the load-bearing body 121. The drill bit 110 is connected to the lower end of the load-bearing body 121. The deflection steering mechanism 130 can drive the drill bit 110 to deflect in a preset direction, so as to drive the drill bit 110 to deflect under the condition of rotation, thereby changing the wellbore 300 trajectory and further realizing a short build-up rate.

[0056] The drive drill string 200 includes a plurality of load-bearing subs 210 connected in sequence from top to bottom. To better adapt to the curvature of the wellbore 300 of the ultra-short radius branch well, preferably, the length of the load-bearing sub 210 is less than 1.2 meters. The lowermost load-bearing sub 210 is connected to the load-bearing body 121, and adjacent two load-bearing subs 210 and between the load-bearing sub 210 and the load-bearing body 121 are hinged through a weight-on-bit and torque deflection transmission mechanism 220, that is, the drive drill string 200 has a hinge structure. The weight-on-bit and torque deflection transmission mechanism 220 can transmit the power of rotary drilling and push the drive drill string 200.

[0057] The drive control sub 280 can be hinged to the steering sub 120 and the lowermost load-bearing sub 210 respectively through the weight-on-bit and torque deflection transmission mechanism 220. Or, the drive control sub 280 can be connected between any adjacent two load-bearing subs 210 through the weight-on-bit and torque deflection transmission mechanism 220. Or, the drive control sub 280 can be connected to the upper end of the drive drill string 200 through the weight-on-bit and torque deflection transmission mechanism 220, that is, the electric drive actuator drive control circuit 230 is arranged behind the load-bearing body 121 to be applicable to accommodating the electric drive actuator drive control circuit with large space requirements and high heat dissipation requirements. And such an arrangement method is not only conducive to minimizing the length of the load-bearing body 121 to improve the passability of the short radius drilling tool, but also conducive to damping the electric drive actuator drive control circuit. Preferably, the length of the drive control sub 280 is less than 1.5 meters. The drive control sub 280 is provided with an electric drive actuator drive control circuit 230. The electric drive actuator drive control circuit 230 is electrically connected to the electric drive actuator 140 through a jumper line 240. The jumper line 240 can cross the weight-on-bit and torque deflection transmission mechanism 220 to electrically connect the electric drive actuator 140 arranged in the load-bearing body 121 and the electric drive actuator drive control circuit 230 arranged in the load-bearing sub 210.

[0058] It should be noted that, such as Figure 6As shown, a pressure-bearing structure is provided inside the drive control sub-section 280, which is generally formed by a pressure-bearing body 281 and a pressure-bearing sleeve 282 to form a sealed chamber, and the electric drive actuator drive control circuit 230 is arranged in the sealed chamber.

[0059] For the short-radius drilling tool of the present invention, by arranging the deflection guiding mechanism 130, the deflection guiding mechanism 130 can drive the drill bit 110 to deflect in a preset direction under the condition of rotation, so as to change the wellbore 300 trajectory, thereby realizing a short build-up rate; by arranging the electric drive actuator drive control circuit 230, which contains a large number of power devices and requires heat dissipation space, in the drive control sub-section 280 behind the bearing body 121, only the deflection guiding mechanism 130 and the electric drive actuator 140 are reserved in the guiding sub-section 120, thus effectively shortening the length of the guiding sub-section 120, and further making it easier to realize the directional function in the high-curvature wellbore 300.

[0060] Furthermore, as Figure 1 、 Figure 2 and Figure 3 shown, the deflection guiding mechanism 130 includes at least three groups of drive hydraulic cylinders 131 arranged at intervals along the circumferential direction of the bearing body 121. Preferably, the drive hydraulic cylinders 131 are arranged at equal intervals. The drive hydraulic cylinder 131 includes a piston cylinder 1311 connected to the cylinder wall of the bearing body 121 and a drive piston 1312 arranged in the piston cylinder 1311. The drive piston 1312 can move radially along the bearing body 121, and the drive piston 1312 can abut against the well wall. By the expansion and contraction of the drive piston 1312, the drill bit 110 is driven to deflect in a preset direction. Specifically, by adjusting the expansion and contraction amount of each drive piston 1312, the thrust applied by each drive piston 1312 to the well wall can be adjusted. The well wall will act on the bearing body 121 through the drive piston 1312 with a reaction force, so that the bearing body 121 drives the drill bit 110 to deflect a certain angle relative to the well wall, thereby changing the wellbore 300 trajectory.

[0061] It should be noted that the purpose and significance of adopting the drive hydraulic cylinder 131 are that the hydraulic pressure can push against the well wall with a flexible and relatively constant pressure and can operate stably within a certain wellbore curvature range without being stuck. In addition, due to the limitation of space in the downhole instrument design, the shapes of the drive piston 1312 and the piston cylinder 1311 are not necessarily standard cylindrical shapes. The drive piston 1312 can be a piston structure, a plunger structure and any equivalent substitutes; any sealing method that helps the expansion and contraction function of the drive piston 1312 can be adopted between the drive piston 1312 and the piston cylinder 1311, such as metal sealing, rubber part sealing or O-ring sealing; the cross-sectional shapes of the piston cylinder 1311 and the drive piston 1312 are adapted to each other, and they can be circular, square or notch-shaped, etc.

[0062] Further, a pusher 1313 is connected to the driving piston 1312, and the driving piston 1312 abuts against the wellbore through the pusher 1313.

[0063] Further, the short-radius drilling tool further includes a strapdown attitude measurement module 270 and a steering control circuit 250. The strapdown attitude measurement module 270 is fixedly arranged in the short-radius drilling tool. Generally speaking, the strapdown attitude measurement module 270 is fixedly arranged on the carrier body 121 and is used to measure the gravity tool face angle and / or magnetic tool face angle of the short-radius controllable trajectory drilling tool underground. The steering control circuit 250 is electrically connected to the strapdown attitude measurement module 270 and the electric actuator drive control circuit 230. The steering control circuit 250 controls the electric actuator 140 to execute the command action according to the measured gravity tool face angle and / or magnetic tool face angle, and further drives the deflection and steering mechanism 130 to drive the drill bit 110 to deflect in the steering direction.

[0064] Further, the deflection and steering mechanism 130 is fixedly arranged on the carrier body 121. The carrier body 121 is fixedly connected to the drill bit 110 and the drive drill string 200 respectively, so that the drive drill string 200 can transmit the drilling pressure torque to the drill bit 110 through the carrier body 121 of the steering sub 120, and the deflection and steering mechanism 130 rotates fully with the drive drill string 200, so as to better clean the wellbore 300 and prevent dragging of the drilling pressure, so that the short-radius drilling tool realizes the steering function under the condition of full rotation.

[0065] Further, as Figure 6 shown, the electric actuator drive control circuit 230 at least includes a switch tube carrier circuit board 231 arranged in a ring shape and a switch tube driver carrier circuit board 232 arranged in a ring shape. Both the switch tube carrier circuit board 231 and the switch tube driver carrier circuit board 232 are arranged in the cylindrical carrier sub 210. Switch tubes are provided on the switch tube carrier circuit board 231, and switch tube drivers are provided on the switch tube driver carrier circuit board 232. The switch tubes are electrically connected to the switch drivers. Such a structure can compress the axial length of the electric actuator drive control circuit 230 to the shortest to improve the passability of the carrier sub 210.

[0066] It should be noted that when the electric actuator 140 is a motor, the switch tubes are used to drive the motor stator coil to generate a sine wave or a square wave to drive the motor to rotate; when the electric actuator is an electromagnet, the switch tubes are used to drive the current conduction state of the electromagnet coil.

[0067] Further, as Figure 6As shown, the short-radius drilling tool further includes a steering control circuit 250. The steering control circuit 250 is electrically connected to the electric drive actuator drive control circuit 230. The steering control circuit 250 is used to drive the electric drive actuator 140 to work through the electric drive actuator drive control circuit 230, so that the piston cylinders 1311 in the sector facing away from the steering direction are in contact with the high-pressure fluid in the internal flow path of the load-bearing body 121 of the steering sub 120.

[0068] Furthermore, as Figure 3 shown, the short-radius drilling device further includes a power supply sub 260. The power supply sub 260 is connected in series at any position in the drive drill string 200, or the power supply sub 260 is connected to the upper end of the drive drill string 200. The power supply sub 260 is used to supply power to the short-radius drilling tool.

[0069] Further, as Figure 2 and Figure 3 shown, the strapdown attitude measurement module 270 is fixedly connected to the load-bearing body 121. The strapdown attitude measurement module 270 includes at least one accelerometer. The accelerometer measures the well inclination angle, and the included angle between the installation direction of the accelerometer and the axis direction of the load-bearing body 121 is between 0° and 60°.

[0070] Further, the strapdown attitude measurement module 270 further includes at least one magnetometer. The magnetometer is used to measure the magnetic azimuth angle near the bit 110. The load-bearing body 121 is made of non-magnetic material to avoid interference with the magnetometer.

[0071] It should be noted that the bit 110 is made of non-magnetic material, which can better avoid interference with the magnetometer.

[0072] Further, at least one of the switch tube driver carrier circuit board 232, the steering control circuit 250, and the strapdown attitude measurement module 270 is manufactured by thick film circuit technology to minimize the occupied space, thereby minimizing the axial length of the carrier sub 210 where each circuit is located, and achieving the purpose of maximizing the passability of the short-radius drilling tool.

[0073] Further, the weight-on-bit torque deflection transmission mechanism 220 includes a transmission universal joint 221 and a fixed sleeve 222 sleeved outside the transmission universal joint 221. There is a gap between the fixed sleeve 222 and the transmission universal joint 221 to form a deflection space. The transmission universal joint 221 can deflect 0° to 15° relative to the axis of the fixed sleeve 222. By restricting the deflection angle of the transmission universal joint 221 through the fixed sleeve 222, it is possible to prevent the weight-on-bit torque deflection transmission mechanism 220 from buckling excessively during the transmission of weight-on-bit torque, which may hinder the transmission of weight-on-bit torque, so that the weight-on-bit torque can be transmitted smoothly.

[0074] Furthermore, the transfer universal joint 221 is provided with a through structure, and a flow pipe 223 for circulating the drilling circulating medium is provided in the through structure.

[0075] It should be noted that the transmission universal joint 221 can be a cross-axis universal joint that can transmit axial force, or a combination of any universal joint and a ball joint.

[0076] Implementation Method 1

[0077] like Figure 1 As shown, the upper end of the drill bit 110 is coaxially connected to a transmission lever 111. Specifically, the transmission lever 111 is cylindrical and is inserted into the interior of the carrier body 121. Preferably, the transmission lever 111 and the drill bit 110 are an integrated structure, or the transmission lever 111 is welded to the upper end of the drill bit 110. The transmission lever 111 is connected to the lower part of the carrier body 121 through a controllable universal joint 112, and a movable gap is formed between the transmission lever 111 and the carrier body 121. The deflection guide mechanism 130 is arranged in the movable gap and is located above the controllable universal joint 112. The driving piston 1312 can abut against the well wall through the transmission lever 111. The extension and contraction of the driving piston 1312 can drive the transmission lever 111 to rotate around the center of the controllable universal joint 112, thereby driving the drill bit 110 to deflect in a preset direction to achieve guidance.

[0078] It should be noted that the length of the upper lever arm of the transmission lever 111 is at least 30% of the distance between the controllable universal joint 112 and the adjacent weight-on-bit torque deflection transmission mechanism 220 above it, so as to fully utilize the space of the supporting body 121 to extend the upper lever arm and enable the drill bit 110 to obtain as much guiding force as possible.

[0079] The length of the lower lever arm of the transmission lever 111 is less than 50% of the distance between the controllable universal joint 112 and the adjacent weight-on-bit torque deflection transmission mechanism 220 above it, so as to minimize the interference of the torque or vibration of the drill bit 110 on the transmission lever 111 and maximize the stability of the steering process.

[0080] The upper lever arm length c of the transmission lever 111 is the distance from the controllable universal joint 112 to the force application point of the deflection guide mechanism 130 to the transmission lever, and the lower lever arm length b is the distance from the lower end surface of the drill bit 110 to the controllable universal joint 112.

[0081] Furthermore, the distance d between the deflection guide mechanism 130 and the upper end of the drill bit 110 is at least 50% of the distance a between the upper end of the drill bit 110 and the adjacent controllable universal joint 112 above it, so that the supporting body 121 can apply sufficient lateral force to the drill bit 110.

[0082] Implementation Method 2

[0083] As Figure 2 shown, the driving hydraulic cylinder 131 is arranged below the WOB torque deflection transmission mechanism 220 connected to the load-bearing body 121, and the distance from the installation position of the driving hydraulic cylinder 131 to the drill bit 110 is less than the distance between the driving hydraulic cylinder 131 and the WOB torque deflection transmission mechanism 220 connected to the load-bearing body 121, so that the acting point of the pushing force is closer to the drill bit 110 and farther from the steering point, thereby driving the drill bit 110 to deflect in the guiding direction;

[0084] The electric drive actuator 140 includes a rotary valve 141 and a drive motor 142. A through-flow channel 1211 is provided on the load-bearing body 121. The rotary valve 141 can periodically connect the through-flow channel 1211 with the driving hydraulic cylinder 131, so that the driving piston 1312 can periodically abut against the well wall as the drill string rotates, thereby obtaining the reaction force of the well wall on the load-bearing body 121 of the guiding sub 120 towards the preset guiding direction, and further driving the drill bit 110 to deflect in the guiding direction. The drive motor 142 is electrically connected to the electric drive actuator drive control circuit 230, and the operation of the motor is controlled through the electric drive actuator drive control circuit 230;

[0085] Furthermore, the rotary valve 141 includes a rotary valve rotor 1411 and a rotary valve stator 1412. The rotary valve stator 1412 is fixedly connected to the load-bearing body 121. The rotary valve stator 1412 is provided with a plurality of valve positions respectively corresponding to the driving hydraulic cylinders 131 one by one. The drive motor 142 includes a drive motor rotor 1421 and a drive motor stator 1422. The drive motor stator 1422 is fixedly connected to the load-bearing body 121. The rotary valve rotor 1411 and the drive motor rotor 1421 are mutually coupled. The drive motor rotor 1421 can drive the rotary valve rotor 1411 to rotate relative to the rotary valve stator 1412, so that the high-pressure drilling fluid is periodically supplied from the valve positions on the rotary valve stator 1412 to the corresponding driving hydraulic cylinders 131, so that the driving piston 1312 generates a thrust periodically.

[0086] It should be noted that the presetting method of the preset guiding direction can be preset before the tool is lowered into the well or during drilling, and signals are transmitted and preset through the pressure change or flow rate change of the mud; the drilling fluid from the drill string water eye enters the inside of the drill bit 110 through the through-flow channel 1211 of the bearing body 121 and then flows into the annulus. Nozzles or other throttling devices 1212 that can generate throttling pressure drops are provided in the flow channel inside the drill bit 110 or between the drill bit 110 and the rotary valve 141. When the drilling fluid flows through the nozzles or throttling structures, a pressure drop will be generated, and this pressure drop is the working pressure difference of the driving hydraulic cylinder 131. The specific process and principle of generating the pressure difference are common knowledge in this field and will not be elaborated here. The term "periodic connection" means that the connectivity between the through-flow channel and the driving hydraulic cylinder changes periodically with the rotation of the short-radius drilling tool to ensure that the driving hydraulic cylinder in a specific sector receives hydraulic pressure to drive the transmission lever to deflect the drill bit in the guiding direction. The term "mutual coupling" refers to a connection method that can ensure the synchronous rotation of the driving motor rotor and the rotary valve rotor, including but not limited to plugging.

[0087] Embodiment 3

[0088] As Figure 3 and Figure 4 shown, the driving hydraulic cylinder 131 is arranged below the weight-on-bit torque deflection transmission mechanism 220 connected to the bearing body 121, and the distance from the setting position of the driving hydraulic cylinder 131 to the drill bit 110 is less than the distance between the driving hydraulic cylinder 131 and the weight-on-bit torque deflection transmission mechanism 220 connected to the bearing body 121, so that the acting point of the pushing force is closer to the drill bit 110 and farther from the turning point, thereby driving the drill bit 110 to deflect in the guiding direction;

[0089] The electric drive actuator 140 includes a rotary valve 141 and a driving motor 142. A through-flow channel 1211 is provided on the bearing body 121. The rotary valve 141 can be periodically connected to the driving hydraulic cylinder 131 through the through-flow channel 1211. The driving motor 142 is electrically connected to the electric drive actuator drive control circuit 230;

[0090] Further, the electric drive actuator 140 includes a plurality of solenoid valves 143 respectively corresponding to the drive hydraulic cylinders 131 one by one. Each solenoid valve 143 is electrically connected to the electric drive actuator drive control circuit 230. The solenoid valve 143 is a two-position two-way solenoid valve 143, which has a first passage 1431 and a second passage 1432. The first passage 1431 is connected to the drive hydraulic cylinder 131, and the second passage 1432 is connected to the through-flow passage 1211. The solenoid valve 143 can periodically connect the flow passage with the drive hydraulic cylinder 131. Specifically, the control circuit of the electric drive actuator 140 opens the passage of the two-position two-way valve corresponding to the drive hydraulic cylinder 131 in the sector opposite to the guiding direction, so that the high-pressure fluid in the water eye passes through the solenoid valve 143 and flows into the piston cylinder 1311 through the through-flow passage 1211, generating a large pressure difference inside and outside the drive hydraulic cylinder 131. Then, the drive piston 1312 is pushed against the wellbore wall to generate a guiding thrust. Correspondingly, the two-position two-way valve corresponding to the drive hydraulic cylinder 131 in the sector where the guiding direction is located is in the closed state, and the drilling fluid in the drive hydraulic cylinder 131 in the sector where the guiding direction is located is discharged from the piston through the throttling device 1212 without generating thrust. Therefore, the drilling fluid in the water eye is periodically distributed to each drive hydraulic cylinder 131 by the solenoid valve 143 under the control of the control circuit of the electric drive actuator 140 as the drill string rotates. The resultant force generated by each drive hydraulic cylinder 131 pushing against the wellbore wall along its radial direction deflects the drill bit 110 to achieve the purpose of changing the trajectory of the wellbore 300.

[0091] It should be noted that the preset method of the preset guiding direction can be preset before the tool is lowered into the well or preset during the drilling process by transmitting signals through the pressure change or flow rate change of the mud; using an electric motor or other means to independently drive the valve to realize the opening / closing between the first passage 1431 and the second passage 1432 belongs to the equivalent replacement of the solenoid valve 143 described in the present invention and is within the protection scope of the present invention.

[0092] In summary, for the short-radius drilling tool of the present invention, by setting the deflection guiding mechanism, the deflection guiding mechanism can drive the drill bit to deflect in the preset direction under the condition of rotation to change the wellbore trajectory, so as to achieve a short build-up rate; by arranging the electric drive actuator drive control circuit, which contains a large number of power devices and requires heat dissipation space, in the drive control short joint behind the load-bearing body, only the deflection guiding mechanism and the electric drive actuator are retained in the guiding short joint, effectively shortening the length of the guiding short joint, and thus making it easier to realize the directional function in high-curvature wellbores.

[0093] The above are only illustrative specific embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention. Moreover, it should be noted that the components of the present invention are not limited to the above overall application. Each technical feature described in the specification of the present invention can be used alone according to actual needs or multiple features can be combined for use. Therefore, the present invention naturally covers other combinations and specific applications related to the inventive points of this case.

Claims

1. A short-radius drilling tool, characterized in that, The short-radius drilling tool includes: A steerable drilling sub-section, which includes a drill bit and a steerable sub-section. The steerable sub-section includes a load-bearing body, on which a deflection guiding mechanism and an electric drive actuator are provided. The drill bit is connected to the lower end of the load-bearing body, and the deflection guiding mechanism can drive the drill bit to deflect in a preset direction; A drive drill string, which includes a plurality of load-bearing sub-sections connected in sequence from top to bottom. The lowermost load-bearing sub-section is connected to the load-bearing body, and adjacent two load-bearing sub-sections and between the load-bearing sub-section and the load-bearing body are all hinged through a weight-on-bit torque deflection transmission mechanism, so that the drive drill string forms a hinge structure; The weight-on-bit torque deflection transmission mechanism includes a transmission universal joint and a fixed sleeve sleeved outside the transmission universal joint. There is a gap between the fixed sleeve and the transmission universal joint to form a deflection space, and the transmission universal joint can deflect relative to the axis of the fixed sleeve in the deflection space; A drive control sub-section, which is provided with an electric drive actuator drive control circuit. The electric drive actuator drive control circuit is electrically connected to the electric drive actuator through a jumper line. The drive control sub-section is connected between the steerable drilling sub-section and the drive drill string, or the drive control sub-section is connected to any position in the drive drill string, or the drive control sub-section is connected to the upper end of the drive drill string; The electric drive actuator drive control circuit is arranged behind the load-bearing body, and the jumper line can cross the weight-on-bit torque deflection transmission mechanism, so that the electric drive actuator arranged in the load-bearing body is electrically connected to the electric drive actuator drive control circuit arranged in the load-bearing sub-section.

2. The short-radius drilling tool according to claim 1, characterized in that The deflection guiding mechanism includes at least three sets of drive hydraulic cylinders arranged at intervals along the circumference of the load-bearing body. The drive hydraulic cylinder includes a piston cylinder connected to the cylinder wall of the load-bearing body and a drive piston arranged in the piston cylinder. The drive piston can abut against the well wall, and the drill bit is driven to deflect in a preset direction by the telescopic movement of the drive piston.

3. The short-radius drilling tool according to claim 1, characterized in that The electric drive actuator drive control circuit at least includes a switch tube bearing circuit board arranged in a ring shape and a switch tube driver bearing circuit board arranged in a ring shape. Switch tubes are provided on the switch tube bearing circuit board, and switch tube drivers are provided on the switch tube driver bearing circuit board. The switch tubes are electrically connected to the switch tube drivers.

4. The short-radius drilling tool according to claim 1, characterized in that The short-radius drilling tool further includes a strapdown attitude measurement module and a steering control circuit. The strapdown attitude measurement module is fixedly arranged in the short-radius drilling tool. The strapdown attitude measurement module can measure the well inclination angle and / or the gravity tool face angle and / or the magnetic tool face angle of the short-radius controllable trajectory drilling tool downhole. The steering control circuit is electrically connected to the strapdown attitude measurement module and the electric drive actuator drive control circuit. The steering control circuit can control the electric drive actuator to execute command actions according to the detection data of the strapdown attitude measurement module.

5. The short-radius drilling tool according to claim 2, wherein A transmission lever is coaxially connected to the upper end of the drill bit. The transmission lever is connected to the lower part of the carrier body through a controllable universal joint, and an activity gap is formed between the transmission lever and the carrier body. The deflection and steering mechanism is arranged in the activity gap and above the controllable universal joint. The drive piston can abut against the well wall through the transmission lever. The expansion and contraction of the drive piston can drive the transmission lever to rotate around the center of the controllable universal joint, and the rotation of the transmission lever can drive the drill bit to deflect in a preset direction.

6. The short-radius drilling tool according to claim 2, wherein The electric drive actuator includes a rotary valve and a drive motor. A through-flow channel is arranged on the carrier body. The rotary valve can periodically connect the through-flow channel with the drive hydraulic cylinder. The drive motor is electrically connected to the electric drive actuator drive control circuit.

7. The short-radius drilling tool according to claim 6, wherein The rotary valve includes a rotary valve rotor and a rotary valve stator. The rotary valve stator is fixedly connected to the carrier body. The rotary valve stator is provided with a plurality of valve positions respectively corresponding to the drive hydraulic cylinders one by one. The drive motor includes a drive motor rotor and a drive motor stator. The drive motor stator is fixedly connected to the carrier body. The rotary valve rotor and the drive motor rotor are mutually coupled, and the drive motor rotor can drive the rotary valve rotor to rotate relative to the rotary valve stator.

8. The short-radius drilling tool according to claim 2, wherein A through-flow channel is arranged on the carrier body. The electric drive actuator includes a plurality of solenoid valves respectively corresponding to the drive hydraulic cylinders one by one. Each solenoid valve is electrically connected to the electric drive actuator drive control circuit. The solenoid valve has a first passage and a second passage. The first passage is communicated with the drive hydraulic cylinder, and the second passage is communicated with the through-flow channel. The solenoid valve can periodically connect the through-flow channel with the drive hydraulic cylinder.

9. The short-radius drilling tool according to claim 4, wherein The steering control circuit is fixedly arranged inside the drive control sub-section, and the steering control circuit is electrically connected to the electric drive actuator drive control circuit inside the drive control sub-section.

10. The short-radius drilling tool according to claim 4 or 9, wherein The guiding control circuit is a guiding control circuit manufactured by using a thick film circuit process.

11. The short-radius drilling tool according to claim 1, wherein the short-radius drilling tool further includes a power sub, the power sub is connected in series at any position in the drive drill string, or the power sub is connected to the upper end of the drive drill string.

12. The short-radius drilling tool according to claim 4, wherein the strapdown attitude measurement module is fixedly connected to the bearing body, and the strapdown attitude measurement module includes at least one accelerometer.

13. The short-radius drilling tool according to claim 12, wherein the strapdown attitude measurement module further includes at least one magnetometer, and the bearing body is a bearing body made of non-magnetic material.

14. The short-radius drilling tool according to claim 12, wherein the strapdown attitude measurement module is a strapdown attitude measurement module manufactured by using a thick film circuit process.

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