An anti-torque automatic balancing device for a screw drill

Abstract

The application provides an anti-torque automatic balancing device for a screw drill, comprising: a shell configured in a cylindrical shape, an upper joint fixedly connected to an upper end of the shell; a hollow core shaft concentrically arranged in the shell; a friction mechanism arranged between the shell and the hollow core shaft in a radial direction; an electrically controlled auxiliary short joint fixedly connected to a lower end of the hollow core shaft; wherein, in a first state, the electrically controlled auxiliary short joint can automatically control the displacement of the drill pipe to continuously adjust the friction torque generated by the friction mechanism, and can make the friction torque equal to and balanced with the anti-torque of the screw drill under the condition that a specific displacement is reached, so that the screw drill performs directional sliding drilling; in a second state, the electrically controlled auxiliary short joint closes the passage in and out of the drill string, and the specific displacement is less than the normal drilling displacement, so that the friction torque generated by the friction mechanism is higher than the anti-torque of the screw drill, so that the screw drill performs composite drilling; the first state and the second state can be switched.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of directional well and horizontal well directional drilling operation, and particularly relates to an anti-torque automatic balancing device for a screw drill. BACKGROUND

[0002] At present, directional wells and horizontal wells mainly use screw drills to control the well trajectory. When sliding drilling, the drill string does not rotate to ensure the stability of the tool face of the screw drill, but this will cause a large axial friction between the drill string and the well wall, especially for long horizontal section horizontal wells and extended reach wells. The huge axial friction will cause the drilling pressure to be not smoothly transmitted, and the mechanical drilling speed is low. In order to solve the low mechanical drilling speed of the screw drill sliding directional drilling, various technologies have been developed at home and abroad. The main idea is to rotate the drill string to reduce the friction, so as to achieve the purpose of improving the mechanical drilling speed.

[0003] There are many schemes in the prior art. For example, by using advanced rotary steering tools, the drill string can be rotated while effectively controlling the well trajectory, thereby overcoming the shortcomings of sliding steering technology, and the drilling pressure is smoothly transmitted, the mechanical drilling speed is high, the well quality is good, however, since the existing rotary steering tool is a mechanical-electrical-hydraulic integrated device, the use and maintenance cost is high, which is not conducive to the reduction of drilling cost.

[0004] There are also researches on large-bend-angle screw composite drilling technology under the premise of maintaining the well trajectory control capability, by reducing the proportion of sliding drilling rig, improving the drilling speed. The research and application of variable diameter stabilizer and other screw steering tools configuration tools and measures, as far as possible to improve the performance of conventional steering tools. However, the large-bend-angle screw drill has a high failure frequency of fracture, wear and other failures when composite drilling, and the proportion of composite drilling is limited.

[0005] There are also changes to the top drive program. When sliding drilling, the top drive first rotates in a positive direction for a certain number of turns, and then reverses for the same number of turns, and the above process is continuously repeated. A certain length of drill string is subjected to continuous positive and negative shock, which can reduce the friction between the drill string and the well wall. The number of positive and negative turns is limited to a certain range. However, the length of the shock is limited, and there is a risk of unhooking

[0006] Chinese patent document ZL201620363357.0 discloses a downhole pipe string rotation control switch which is placed at a position about 300m above the screw drill tool. The switch can be opened by drilling fluid. When the drill string rotates, the friction force of the drill string about 300m is used to overcome the counter torque of the screw drill tool, so as to achieve the target of rotating the drill string during directional drilling. However, the downhole pipe string rotation control switch uses the gravity of the drill string to generate friction force, which is greatly affected by the motion state. The screw drill tool may not be stabilized, and the drill string about 300m cannot rotate, which reduces the proportion of the drill string rotation and seriously affects the effect of reducing friction and increasing speed.

[0007] Chinese patent document CN201220454297 discloses an up-and-down sliding drilling friction reduction and torque reduction tool, which proposes a tool for reducing resistance by using an up-and-down control mode. However, there is severe axial vibration in the actual drilling process, which may cause control difficulty. Moreover, the design of the transmission part is not involved, and the short section which bears an axial force of about 100KN will be quickly worn, so the practicability is poor. SUMMARY

[0008] In view of the above technical problems, the present application aims to provide an anti-torque automatic balancing device for a screw drill tool, which can automatically adjust the screw drill tool in a composite drilling mode and a directional sliding drilling mode. In the composite drilling state, the mechanical drilling speed is high, and the friction mechanism is not worn. In the sliding drilling state, the anti-torque automatic balancing device can automatically balance the anti-torque of the screw drill tool, and can make the friction torque generated by the device always balance the anti-torque of the screw drill tool with high efficiency and high precision, thereby greatly reducing the axial friction and improving the mechanical drilling speed while keeping the tool face of the screw drill tool stable.

[0009] To this end, the present application provides an anti-torque automatic balancing device for a screw drill tool, which comprises a housing configured in a cylindrical shape, an upper joint for connecting an upper drill string fixedly connected to an upper end of the housing, a hollow shaft concentrically arranged in the housing, a friction mechanism arranged between the housing and the hollow shaft in a radial direction, and an electrically controlled auxiliary short section fixedly connected to a lower end of the hollow shaft. In a first state, the electrically controlled auxiliary short section can automatically control the displacement of the drill rod to continuously adjust the friction torque generated by the friction mechanism, and can make the friction torque equal to and balance the anti-torque of the screw drill tool when a certain displacement condition is reached, so that the screw drill tool performs directional sliding drilling. In a second state, the electrically controlled auxiliary short section closes the passage inside and outside the drill string, and the certain displacement is smaller than the normal drilling displacement, so that the friction torque generated by the friction mechanism is higher than the anti-torque of the screw drill tool, thereby making the screw drill tool perform composite drilling. The first state and the second state can be switched.

[0010] In one embodiment, the friction mechanism comprises: an annular piston sleeved on the hollow core shaft; and a plurality of friction stators and friction rotors alternately sleeved on the hollow core shaft and at the lower end of the annular piston; wherein the friction stators are fixedly connected with the inner wall of the shell in the circumferential direction, the friction rotors are fixedly connected with the hollow core shaft in the circumferential direction, and the annular piston can move axially downward under the action of hydraulic pressure to make the friction stators tightly fit with the friction rotors, so that the friction mechanism can generate a friction torque when the shell rotates relative to the hollow core shaft.

[0011] In one embodiment, a plurality of limiting grooves are provided on the inner wall of the shell, and a plurality of limiting protrusions are provided on the outer circumferential surface of the friction stator, the limiting protrusions being capable of being fitted into the limiting grooves, so that the friction stator and the shell are fixedly connected in the circumferential direction.

[0012] In one embodiment, a first involute tooth is provided on the outer wall of the hollow core shaft, and a second involute tooth is provided on the inner wall of the friction rotor, the first involute tooth being capable of being fitted with the second involute tooth, so that the friction rotor and the hollow core shaft are fixedly connected in the circumferential direction.

[0013] In one embodiment, the tooth height of the first involute tooth and the second involute tooth is set to be lower than 3mm.

[0014] In one embodiment, a hydraulic passage is formed at the upper end of the annular piston, the hydraulic passage being in communication with the central flow channel of the hollow core shaft, and the hydraulic passage being capable of transmitting the hydraulic pressure in the hollow core shaft to the upper end surface of the annular piston, so that the annular piston generates an axial thrust to push the friction stator and the friction rotor to tightly fit.

[0015] In one embodiment, a first seal and a second seal are respectively provided between the annular piston and the hollow core shaft and the shell.

[0016] In one embodiment, the electrically controlled auxiliary short section comprises: a lower joint configured as a hollow cylinder, a side wall of the lower joint being provided with a through hole; a main valve arranged in the lower joint, the main valve being provided with a leakage passage and a valve core inside, two ends of the leakage passage being in communication with the inside of the lower joint and the through hole respectively; a sealed cabin fixedly connected with the main valve body, the sealed cabin being provided with a motor, a calculation control module, a gravity sensor and a power supply inside, the calculation control module being signal connected with the gravity sensor and the motor respectively, an output end of the motor being in circumferential fixed connection with the valve core; wherein the gravity sensor can measure the angular position and the rotating speed of the lower joint, the calculation control module can collect the measurement data of the gravity sensor in real time and control the motor to rotate to drive the valve core to move axially to adjust the opening size of the leakage passage, so as to automatically control the displacement of the drill pipe.

[0017] In one embodiment, the electrically controlled auxiliary short section further comprises a pressure sensor for measuring the pressure in the drill string.

[0018] In one embodiment, the main valve comprises an outer cylinder and an inner cylinder concentrically arranged in the outer cylinder, the outer cylinder being used for fixed connection with the inner wall of the lower joint, the sealed cabin being arranged at the axial end of the inner cylinder, the inner cylinder being connected with the outer cylinder through radially symmetrically distributed connecting parts, so as to form an axially extending drilling fluid flow channel between the inner cylinder and the outer cylinder.

[0019] In one embodiment, the hollow core shaft is rotatably connected with the shell through a bearing assembly, a step with a downward end face is arranged on the inner wall of the upper joint, and the bearing assembly is arranged between the step and the upper end face of the shell.

[0020] In one embodiment, an annular protrusion is arranged on the outer wall of the hollow core shaft, and the bearing assembly is fixedly connected with the hollow core shaft through the annular protrusion and a fastener.

[0021] In one embodiment, a drop prevention ring is further fixedly connected with the lower end of the hollow core shaft.

[0022] Compared with the prior art, the application has the following advantages:

[0023] The automatic anti-torque balancing device for screw drills according to the present invention can automatically adjust the screw drill's composite drilling mode and directional sliding drilling mode. It can switch between drill string-rotary sliding drilling and composite drilling using a specific pump switching program, offering simple operation and high efficiency. In composite drilling mode, the mechanical drilling rate is high, and there is no wear on the friction stator and friction rotor in the friction mechanism. In sliding drilling mode, the automatic anti-torque balancing device can automatically balance the anti-torque of the screw drill, allowing the screw drill to rotate the drill string during sliding drilling to smoothly transmit drilling pressure and effectively control the tool face. It also significantly reduces axial friction, thereby maintaining the stability of the screw drill tool face while greatly increasing the mechanical drilling rate, effectively solving problems such as pressure buildup and low mechanical drilling rate in sliding drilling. Furthermore, the use of an electrically controlled auxiliary sub to control the discharge flow rate to adjust the drilling fluid discharge ensures that the friction torque generated by the friction mechanism is always in high-efficiency and high-precision balance with the screw anti-torque, greatly improving the efficiency and accuracy of discharge adjustment. The anti-torque automatic balancing device enables the screw drill to automatically switch working states according to actual working conditions, which greatly improves drilling efficiency and significantly enhances drilling results. Attached Figure Description

[0024] The present invention will now be described with reference to the accompanying drawings.

[0025] Figure 1 The structure of an automatic anti-torque balancing device for screw drills according to the present invention is shown.

[0026] Figure 2 Showing Figure 1 The structure of the electronically controlled auxiliary section in the anti-torque automatic balancing device shown.

[0027] Figure 3 yes Figure 2 A cross-sectional view along line AA in the middle.

[0028] Figure 4 yes Figure 2 A sectional view along line BB.

[0029] Figure 5 yes Figure 2 A sectional view along the center line CC.

[0030] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0031] The invention will now be described with reference to the accompanying drawings.

[0032] In this application, it should be noted that the end of the anti-torque automatic balancing device for screw drills according to the present invention that is lowered into the wellbore and furthest from the wellhead is defined as the lower end or a similar term, and the end closer to the wellhead face is defined as the upper end or a similar term. Furthermore, in this application, the term "radial" refers to along... Figure 1 The vertical direction in the text, referred to as "axial direction", means along the direction of the axis. Figure 1 The horizontal direction in the middle.

[0033] Figure 1 The structure of an automatic anti-torque balancing device 100 for a screw drill tool according to the present invention is shown. Figure 1 As shown, the automatic anti-torque balancing device 100 includes a cylindrical housing 2, a hollow mandrel 3, a friction mechanism 4, and an electrically controlled auxiliary sub 5. The hollow mandrel 3 is concentrically arranged within the housing 2, and its interior forms a central flow channel extending axially for drilling fluid circulation. The friction mechanism 4 is disposed radially between the housing 2 and the hollow mandrel 3, and generates frictional torque. The electrically controlled auxiliary sub 5 is fixedly connected to the lower end of the hollow mandrel 3, and automatically controls the drill pipe displacement, thereby adjusting the magnitude of the frictional torque generated by the friction mechanism 4. Through the electrically controlled auxiliary sub 5, the automatic anti-torque balancing device 100, under specific displacement conditions, ensures that the frictional torque generated by the friction mechanism 4 is equal to and balanced with the anti-torque of the screw drill string, thus achieving automatic balancing of the anti-torque of the screw drill string for directional sliding drilling operations. Furthermore, the electronically controlled auxiliary sub 5 can close the inner and outer channels of the drill string and make a specific displacement less than the normal drilling displacement, so that the friction torque generated by the friction mechanism 4 is higher than the reverse torque of the screw drill string, so that the drill string can perform compound drilling operations.

[0034] The automatic anti-torque balancing device 100 can automatically adjust according to the actual working conditions, thereby selecting between directional sliding drilling and combined drilling operations. Furthermore, in directional sliding drilling, the friction torque generated by the friction mechanism 4 automatically balances the anti-torque of the screw drill bit, ensuring the screw drill bit housing does not rotate while the drill string rotates, thus reducing axial friction and increasing the mechanical drilling speed during directional drilling. In combined drilling, the friction torque generated by the friction mechanism 4 is higher than the anti-torque of the screw drill bit, causing the screw drill bit stator (housing) to rotate, and the drill string also rotates, significantly increasing the mechanical drilling speed in combined drilling operations. This is highly beneficial for improving screw drill bit performance, enhancing drilling efficiency, and increasing construction efficiency.

[0035] The anti-torque automatic balancing device 100 according to the present invention is installed at a certain position above the screw drill bit, and can realize drill string-rotation sliding drilling and combined drilling by using a specific pump switching program. For example, the anti-torque automatic balancing device 100 can be installed at a position about 50m above the screw drill bit.

[0036] As shown in Figure 1 the upper end of the housing 2 is fixedly connected with an upper joint 1, and the upper joint 1 is used for connecting an upper drill string and a drilling pump (not shown). In one embodiment, the housing 2 is fixedly connected with the upper joint 1 through a stepped threaded connection buckle. Moreover, the upper end surface of the housing 2 extends to the axial inner side of the upper joint 1. The upper joint 1 is configured as a special buckle type, and is connected with the upper drill string through the special buckle type. The connection mode of the upper joint 1 not only can effectively ensure the reliability of the connection between the components, but also is convenient and fast for installation and disassembly.

[0037] According to the present application, the hollow mandrel 3 is rotatably connected with the housing 2 through a bearing assembly 7. As shown in Figure 1 the hollow mandrel 3 is concentrically arranged in the inside of the housing 2 through the bearing assembly 7. A step with a downward end surface is provided on the inner wall of the upper joint 1, and the bearing assembly 7 is arranged between the step and the housing 2, and the axial end surfaces of the outer rings of the bearing assembly 7 are respectively in contact with the end surface of the step and the upper end surface of the housing 2, so as to form axial limiting. Therefore, the hollow mandrel 3 can freely rotate relative to the housing 2 and the upper joint 1 through the bearing assembly 7, while bearing axial forces such as drilling pressure.

[0038] In the present embodiment, an annular protrusion 31 is provided on the outer wall of the hollow mandrel 3, and the annular protrusion 31 is preferably arranged at a position close to the upper end of the hollow mandrel 3. The bearing assembly 7 is fixedly connected with the hollow mandrel 3 through a fastener 32 and the annular protrusion 31. The bearing assembly 7 is sleeved on the hollow mandrel 3, and the axial inner end surface of the inner ring of the bearing assembly 7 abuts against the upper end surface of the annular protrusion 31, and the fastener 32 is installed on the axial outer end surface of the inner ring of the bearing assembly 7, so as to fasten the bearing assembly 7. In one embodiment, the fastener 32 can adopt a fixed nut.

[0039] According to the present application, the friction mechanism 4 includes an annular piston 41 sleeved on the hollow mandrel 3, and a plurality of friction stators 42 and friction rotors 43 which are alternately sleeved on the hollow mandrel 3 in sequence. The friction stators 42 and the friction rotors 43 can be made of, for example, cemented carbide material. As shown in Figure 1 the annular piston 41 is arranged below the bearing assembly 7, and the friction stators 42 and the friction rotors 43 are arranged at the lower end of the annular piston 41. The friction stators 42 are fixedly connected with the inner wall of the housing 2 in the circumferential direction, and the friction rotors 43 are fixedly connected with the hollow mandrel 3 in the circumferential direction. The lower end surface of the annular piston 41 abuts against the upper end surface of the uppermost friction stator 42.

[0040] In actual operation, the annular piston 41 can generate an axial downward thrust under the action of hydraulic pressure, and act on the uppermost friction stator 42, thereby pushing the friction stator 42 and the friction rotor 43 to closely adhere, so that the friction mechanism 4 can generate a friction torque when the housing 2 rotates relative to the hollow core shaft 3. The friction torque generated by the friction mechanism 4 is related to the number of friction stator 42 and friction rotor 43, friction coefficient, size and the force of the annular piston 41. In actual operation, the friction torque generated by the friction mechanism 4 can be adjusted according to the need to adjust the above parameters.

[0041] According to an embodiment of the present application, the friction stator 42 is configured as a circular ring, and the inner ring of the friction stator 42 is in clearance fit with the hollow core shaft 3. A plurality of limiting grooves (not shown) are provided on the inner wall of the housing 2, and a plurality of limiting protrusions (not shown) are provided on the outer peripheral surface of the friction stator 42. The limiting protrusions can be fitted into the limiting grooves, so that the friction stator 42 and the housing 2 are fixedly connected in the circumferential direction. Preferably, the plurality of limiting grooves are uniformly spaced apart in the circumferential direction of the housing 2, and correspondingly, the plurality of limiting protrusions are uniformly spaced apart in the circumferential direction of the friction stator 42.

[0042] According to an embodiment of the present application, the friction rotor 43 is configured as a circular ring, and a gap is left between the friction rotor 43 and the housing 2. A first involute tooth (not shown) is provided on the outer wall of the hollow core shaft 3, and a second involute tooth (not shown) is provided on the inner wall of the friction rotor 43. The first involute tooth can be fitted with the second involute tooth, so that the friction rotor 43 and the hollow core shaft 3 are fixedly connected in the circumferential direction. The first involute tooth and the second involute tooth are densely distributed in the circumferential direction. The tooth height of the first involute tooth and the second involute tooth is set to be less than 3mm. Thus, a shallow and dense involute tooth connection structure is formed. In this way, not only can a larger torque be transmitted, but also the influence on the strength of the hollow core shaft 3 can be reduced.

[0043] As shown in Figure 1 A hydraulic passage 6 is formed at the upper end of the annular piston 41, and the hydraulic passage 6 is between the radial direction of the housing 2 and the hollow core shaft 3. The hydraulic passage 6 communicates with the central flow passage of the hollow core shaft 3, and the hydraulic passage 6 can transmit the hydraulic pressure in the hollow core shaft 3 to the upper end surface of the annular piston 41, so that the annular piston generates an axial thrust and acts on the uppermost friction stator 42, thereby pushing the friction stator 42 and the friction rotor 43 to closely adhere.

[0044] In the embodiment, in order to ensure that the hydraulic pressure can effectively act on the annular piston 41, a first sealing member 411 is arranged between the annular piston 41 and the outer wall surface of the hollow core shaft 3, and a second sealing member 412 is arranged between the annular piston 41 and the inner wall surface of the housing 2. In this way, the sealing between the annular piston 41 and the hollow core shaft 3 and the housing 2 can be effectively ensured, thereby ensuring the sealing of the hydraulic passage 6. The first sealing member 411 and the second sealing member 412 can be Galy ring seals with wear resistance.

[0045] As shown in Figure 1 , the lower end of the hollow core shaft 3 is also fixedly connected with a drop-preventing ring 8. Preferably, the drop-preventing ring 8 can be fixedly connected with the housing 2 in a threaded connection manner. In the operation process, when the bearing assembly 7 has a problem, the drop-preventing ring 8 can support the hollow core shaft 3, the annular piston 41, and the friction stator 42 and the friction rotor 43, thereby preventing the hollow core shaft 3, the annular piston 41, and the friction stator 42 and the friction rotor 43 from falling into the well.

[0046] According to the present application, as shown in Figure 2 and Figure 2 , the electrically-controlled auxiliary joint 5 includes a lower joint 50, a main valve 51 arranged in the lower joint 50, a leakage passage 52 and a valve core 53 arranged in the main valve 51, a sealed cabin 54 fixedly connected with the main valve 51, and a motor 55, a calculation control module 56, a gravity sensor 57 and a power supply 58 arranged in the sealed cabin. The calculation control module 56 is signal-connected with the gravity sensor 57 and the motor 55 respectively, and the output end of the motor 55 is fixedly connected with the valve core 53. The power supply 58 is connected with the motor 55, the calculation control module 56 and the gravity sensor 57 respectively for providing electric energy. The electrically-controlled auxiliary joint 5 can measure the angular position and the rotating speed of the lower joint 50 through the gravity sensor 57, and the calculation control module 56 can collect the measurement data of the gravity sensor 57 in real time and control the motor 55 to rotate to drive the valve core 53 to move axially, so as to adjust the opening size of the leakage passage 52, thereby automatically controlling the displacement of the drill pipe.

[0047] In one embodiment, the upper end of the lower joint 50 is configured as a standard thread for fixedly connecting with the hollow core shaft 3. The upper end of the lower joint 50 extends upward to the axial inner side of the housing 2, and the upper end surface of the lower joint 50 is in contact with the friction rotor 43 at the lowermost end, thereby forming axial limiting for the friction rotor 43. In addition, the outer diameter of the upper end connecting portion of the lower joint 50 is smaller than the outer diameter of the main body structure of the lower joint 50, and a gap is left between the outer wall surface of the upper end connecting portion and the drop-preventing ring 8. The lower end of the lower joint 50 is configured as a special pin type for connecting with the lower drill string (drill pipe). For example, the lower end of the lower joint 50 is connected with the lower drill string, the screw drill tool and the drill bit in sequence.

[0048] As shown in Figure 5and Figure 2 As shown, the main valve 51 includes an outer cylinder 511 and an inner cylinder 512, with the inner cylinder 512 concentrically distributed inside the outer cylinder 511. The inner cylinder 512 is connected to the outer cylinder 511 via radially symmetrically distributed connecting portions 513. This creates two axially extending drilling fluid channels 514 between the inner cylinder 512 and the outer cylinder 511, and these two channels 514 are radially symmetrically distributed. Preferably, the axial length of the inner cylinder 512 can be set to be less than the axial length of the outer cylinder 511, and one end of the inner cylinder 512 is flush with one end of the outer cylinder 511. The connecting portions 513 are located radially between the outer cylinder 511 and the inner cylinder 512 and extend radially, while also extending a portion axially. The outer cylinder 511 is used for fixed connection to the inner wall of the lower connector 50, and the sealing chamber 54 is located at the axial end of the inner cylinder 512. Figure 2 In the illustrated embodiment, the lower end face of the inner cylinder 512 is flush with the lower end face of the outer cylinder 511, and the sealing chamber 54 is disposed at the upper axial end of the inner cylinder 512. Of course, it can be understood that the upper end face of the inner cylinder 512 can be flush with the upper end face of the outer cylinder 511, and the sealing chamber 54 can also be disposed at the lower axial end of the inner cylinder 512.

[0049] like Figure 3 and Figure 4 As shown, the sealed chamber 54 is cylindrical, with its upper end closed and its lower end open. The lower end of the sealed chamber 54 is fixedly connected to the axial end of the inner cylinder 512 of the main valve 51, forming a seal. The motor 55, the calculation and control module 56, the gravity sensor 57, and the power supply 58 are all arranged inside the sealed chamber 54. The motor 55, the calculation and control module 56, and the gravity sensor 57 are all powered by the power supply 58. A mounting plate is also provided on the inner wall of the sealed chamber 54 near the lower end. The motor 55 is mounted on the mounting plate, and the output shaft 551 of the motor 55 passes through the mounting plate axially and extends outward to connect to the valve core 53.

[0050] In one embodiment, such as Figure 2 As shown, the output shaft 551 of the motor 55 is constructed with an internal hexagonal structure. Meanwhile, one end of the valve core 53 ( Figure 2 The left end of the valve core 53 is constructed with an external hexagonal structure. The valve core 53 and the output shaft 551 of the motor 55 are connected circumferentially through the external and internal hexagonal structures, while allowing axial sliding relative to the output shaft 551. A threaded hole is provided along the central axis in the inner cylinder 512 of the main valve 51. The valve core 53 is axially mounted in the threaded hole and forms a threaded connection with the threaded hole of the inner cylinder 512. The motor 55 can rotate forward or reverse under the control of the calculation and control module 56. Thus, the motor 55 can drive the valve core 53 to rotate, causing the valve core 53 to move axially along the inner cylinder 512.

[0051] According to one embodiment of the present application, two gravity sensors 57 are provided, and the two gravity sensors 57 are distributed perpendicular to each other. The two gravity sensors 57 can measure the angular position and rotational speed of the lower sub 50, and can transmit the collected measurement data to the computing control module 56 in real time.

[0052] As shown in Figure 5 and Figure 2 , a through hole 501 extending in the radial direction is provided on the side wall of the lower sub 50, and the two ends of the flow relief passage 52 are respectively communicated with the internal passage of the lower sub 50 and the through hole 501. The flow relief passage 52 includes a first flow channel 521, a second flow channel 522 and a third flow channel 523 communicated in sequence. The first flow channel 521 penetrates the side wall of the inner cylinder 512 and is communicated with the corresponding side of the drilling fluid flow channel 514. The second flow channel 522 is arranged along the central axis of the inner cylinder 512 and is distributed in the interior of the inner cylinder 512, and one end of the second flow channel 522 is communicated with the threaded hole in which the valve core 53 is installed. The third flow channel 523 extends in the radial direction and penetrates the inner cylinder 512, the connecting part 513 and the outer cylinder 511 in sequence, and is communicated with the through hole 501 on the side wall of the lower sub 50. The valve core 53 can control the size of the communication port between the second flow channel 522 and the first flow channel 521 through axial movement, so as to realize the adjustment of the opening size of the flow relief passage 52, thereby realizing the control of the displacement of the drill pipe.

[0053] As shown in ​ , the electrically controlled auxiliary short section 5 further includes a pressure sensor 59 for measuring the pressure in the drill string. The pressure sensor 59 is arranged outside the sealed cabin 54, and the pressure sensor 59 is connected with the computing control module 56 and the power supply 58.

[0054] The anti-torque automatic balancing device 100 for the screw drill according to the present application is installed at a certain position above the screw drill. When the screw drill is normally drilled, the screw drill and the drill bit will generate pressure loss, and the pressure loss generated by the screw drill accounts for the majority, which causes the pressure difference between the hydraulic passage 6 between the hollow shaft 3 and the shell 2 and the annular space outside the shell 2. Thus, the upper end surface of the annular piston 41 is in communication with the high-pressure area formed by the hydraulic passage 6, and the lower end is in communication with the low-pressure area outside the shell 2 through the friction stator 42 and the friction rotor 43. Therefore, the annular piston 41 is subjected to the action of the liquid pressure. When the rotor of the screw drill outputs torque, the stator (shell) is subjected to an anti-torque of the same size and opposite direction, and the direction of the anti-torque is counterclockwise. According to the working characteristics of the screw drill, when the output torque of the screw increases, the pressure loss generated by the screw also increases, and the two are in a proportional relationship. The axial pushing force generated by the annular piston 41 also increases, and the rotation of the upper joint 1 and the shell 2 driven by the rotating disc makes the friction torque between the friction stator 42 and the friction rotor 43 also increase. The direction of the friction torque is clockwise. Therefore, as long as the size of the friction torque is the same as the anti-torque of the screw drill, the stator of the screw drill is in a torque balance state, thereby keeping a non-rotating state, and thus the screw drill performs directional sliding drilling operation. At this time, the anti-torque automatic balancing device 100 is in a first state. In this state, the friction torque generated by the friction mechanism 4 can automatically balance the anti-torque of the screw drill, so that the shell of the screw drill does not rotate but the drill string rotates, thereby achieving the effect of reducing the axial friction resistance and improving the rate of penetration during directional drilling.

[0055] When the anti-torque automatic balancing device 100 is in the first state, the displacement is adjusted through the electrically controlled auxiliary short section 5. When the displacement is adjusted to a certain displacement Q0, the certain displacement can meet the normal drilling. The friction torque is equal to the anti-torque of the screw, and even if the anti-torque of the screw changes due to drilling complex strata or drilling pressure, the two are still balanced. Thus, the effect of automatically balancing the anti-torque of the screw drill by the friction torque is achieved, and the shell of the screw drill is in a non-rotating state due to force balance, thereby directional sliding drilling can be performed. The certain displacement Q0 is related to the characteristics of the screw, the wear of the friction stator 42 and the friction rotor 43. When used in the field, the certain displacement Q0 needs to be determined through repeated testing of the electrically controlled auxiliary short section 5, and it also needs a long time to place the tool. The electrically controlled auxiliary short section 5 can significantly improve the efficiency and accuracy of adjusting the displacement.

[0056] When the displacement of the drilling fluid increases and deviates from the certain displacement Q0, the friction torque generated by the friction mechanism 4 will be greater than the torque generated by the screw drill, and the two are no longer balanced. The stator (shell) of the screw drill will also rotate with the drill string, and thus the screw drill performs composite drilling operation. At this time, the anti-torque automatic balancing device 100 is in a second state. In this state, the rate of penetration in the composite drilling operation state can be greatly improved, which is very beneficial to improve the drilling efficiency of the screw drill.

[0057] The working process of the anti-torque automatic balancing device 100 for the screw drill according to the present application is briefly described below.

[0058] In actual operation, the pressure in the drill string is low when the pump is off and high when the pump is on, so the on-off pump state can be determined through the pressure sensor 59, and the pump can be controlled through the on-pump-off-pump program by programming.

[0059] During field operation, when composite drilling is needed, the pump-off time is higher than 30 seconds, and then the rotary table is started. The calculation control module 56 commands the motor 55 to drive the valve core 53 to rotate forward, and the valve core 53 moves downward until the drain passage 52 is closed, so that the inside and outside passages of the drill string are closed. At this time, the displacement of the lower end screw drill and the drill bit is the displacement of the drilling pump. Because the sealing pre-tightening degree is designed to make the specific displacement smaller than the normal drilling displacement, the friction mechanism 4 generates a friction torque much higher than the screw reverse torque under the normal displacement condition, and the screw drill enters the composite drilling state.

[0060] When directional sliding drilling is needed, first rotate the tool face to the designed position according to the normal direction program, then turn off the pump, and the pump-off time is less than 30 seconds. After the pump is turned on, the calculation control module 56 first collects the data of the gravity sensor 57 and automatically records the angle position, and then commands the motor 55 to drive the valve core 53 to move until the middle position. Part of the drilling fluid is drained to the annulus through the drain passage 52, reducing the displacement flowing through the screw drill. After the pump is turned on for 2 minutes, the rotary table is started, and the drilling pressure is gradually increased to the designed value. The calculation control module 56 collects the data of the gravity sensor 57 in real time. The calculation control module 56 judges the rotation direction through the angle change of the lower sub 50, and the specific process is as follows:

[0061] If the lower sub 50 rotates forward, it means that the torque generated by the anti-torque automatic balancing device 100 is too large, so the calculation control module 56 commands the motor 55 to reverse 0.5 turns, driving the valve core 53 to move upward. The opening of the drain passage 52 becomes larger, the drain flow increases, the displacement flowing through the screw drill decreases, and the friction torque generated by the friction mechanism 4 becomes smaller.

[0062] If the lower sub 50 rotates backward, it means that the torque generated by the anti-torque automatic balancing device 100 is too small, so the calculation control module 56 commands the motor 55 to rotate forward 0.5 turns, driving the valve core 53 to move downward. The opening of the drain passage 52 becomes smaller, the drain flow decreases, the displacement flowing through the screw drill increases, and the friction torque generated by the friction mechanism 4 becomes larger.

[0063] If the lower sub 50 does not rotate, the motor 55 and the valve core 53 are stationary.

[0064] Thus, the displacement is continuously and automatically adjusted by the electrically controlled auxiliary segment 5 until the lower joint 50 does not rotate, indicating that the friction torque of the automatic anti-torque balancing device 100 is the same as the anti-torque of the screw drill. At this time, the displacement flowing through the screw drill and the drill bit is a specific displacement Q0, i.e., the displacement of the drilling pump minus the leakage flow through the leakage passage 52, and the friction torque generated by the friction mechanism 4 is always equal to the screw anti-torque, and the screw drill housing is in a non-rotating state. The screw drill enters the state of directional sliding drilling.

[0065] During the drilling operation of the screw drill, the automatic anti-torque balancing device 100 is installed at a position close to the upper part of the screw drill for a certain length. The screw drill is lowered into the well to start drilling. If the well trajectory composite design requirement is met, the rotary table is started and the pump is started, then the pump is stopped, and the pump is restarted after 30 seconds. At this time, the friction torque generated by the friction mechanism 4 is higher than the anti-torque of the screw drill, the screw drill stator is in a rotating state, the drill string is also in a rotating state, the screw drill is in a composite drilling state, the screw drill mechanical drilling speed is high, and the friction stator 42 and the friction rotor 43 are not worn. The screw drill has no well trajectory control capability.

[0066] After drilling for a distance, if the well trajectory deviates from the design and directional drilling is required, first place the tool face to the design position, start the pump-stop the pump for less than 30 seconds-start the pump, then start the rotary table, and automatically adjust the displacement of the drill string to the specific displacement Q0 through the electrically controlled auxiliary segment 5, so that the screw drilling enters the state of directional sliding. At this time, the friction torque generated by the friction mechanism 4 can automatically balance the anti-torque of the screw drill, so that the screw drill housing does not rotate but the drill string rotates, achieving the effect of reducing the axial friction and improving the mechanical drilling speed during directional drilling. After a period of drilling, the drill string reaches the well trajectory design target again, and the displacement of the drilling fluid is adjusted to the composite drilling state again through the electrically controlled auxiliary segment 5.

[0067] The anti-torque automatic balancing device 100 for the screw drill according to the present application can realize automatic adjustment of the screw drill composite drilling mode and the directional sliding drilling mode, and can realize switching of the drill string-rotary sliding drilling and the composite drilling by using a specific switch pump program, which is simple to operate and high in efficiency. In the composite drilling state, the mechanical drilling speed is high, and the friction stator 42 and the friction rotor 43 in the friction mechanism 4 are not worn. In the sliding drilling state, the anti-torque automatic balancing device 100 can automatically balance the screw drill anti-torque, so that the screw drill can rotate the drill string to smoothly transfer the drilling pressure when sliding drilling, and can effectively control the tool of the tool face, and greatly reduce the axial friction resistance, thereby greatly improving the mechanical drilling speed while keeping the tool face of the screw drill stable, and effectively solving the problems of sliding drilling pressure bearing and low mechanical drilling speed. Moreover, the flow discharge is controlled by using the electrically controlled auxiliary short section 5 to adjust the drilling fluid discharge, so that the friction torque generated by the friction mechanism 4 is always balanced with the screw anti-torque with high efficiency and high precision, which greatly improves the efficiency and precision of adjusting the discharge. The anti-torque automatic balancing device 100 enables the screw drill to automatically switch the working state according to the actual working condition, greatly improves the drilling construction efficiency, and significantly enhances the drilling construction effect.

[0068] In the description of the present application, it should be understood that the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0069] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0070] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0071] Finally, it should be noted that the above only describes the preferred embodiments of the present application and does not constitute any limitation on the present application. Although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements to some technical features thereof. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A counter-torque automatic balancing device for a screw drill, comprising: a housing (2) configured in a cylindrical shape, an upper joint (1) for connecting an upper drill string fixedly connected to an upper end of the housing; a hollow core shaft (3) concentrically arranged in the housing; a friction mechanism (4) arranged between the housing and the hollow core shaft in a radial direction; and an electrically controlled auxiliary sub (5) fixedly connected to a lower end of the hollow core shaft; wherein, in a first state, the drill pipe displacement can be automatically controlled by the electrically controlled auxiliary sub to continuously adjust the friction torque generated by the friction mechanism, and the friction torque can be equal to and balanced with the counter-torque of the screw drill under the condition that a certain displacement is reached, so that the screw drill performs directional sliding drilling, in a second state, the inner and outer passages of the drill string are closed by the electrically controlled auxiliary sub, and the certain displacement is smaller than the normal drilling displacement, so that the friction torque generated by the friction mechanism is higher than the counter-torque of the screw drill, thereby making the screw drill perform composite drilling, the first state and the second state can be switched; the electrically controlled auxiliary sub comprises: a lower joint (50) configured in a hollow cylindrical shape, a side wall of the lower joint being provided with a through hole (501); a main valve (51) arranged in the lower joint, the main valve being provided with a flow discharge channel (52) and a valve core (53) therein, two ends of the flow discharge channel being in communication with the inside of the lower joint and the through hole respectively, and the valve core moving axially to adjust the opening size of the flow discharge channel, thereby controlling the drill pipe displacement; a sealed cabin (54) fixedly connected with the main valve, the sealed cabin being provided with a motor (55), a calculation control module (56), a gravity sensor (57), and a power supply (58) therein, the calculation control module being signal connected with the gravity sensor and the motor respectively, and an output end of the motor being in circumferential fixed connection with the valve core; wherein, the gravity sensor can measure the angular position and rotational speed of the lower joint, the calculation control module can collect the measurement data of the gravity sensor in real time, and control the motor to rotate to drive the valve core to move axially, so as to adjust the opening size of the flow discharge channel, thereby automatically controlling the drill pipe displacement; the main valve comprises an outer cylinder (511) and an inner cylinder (512) concentrically arranged in the outer cylinder, the outer cylinder being used for fixedly connecting with the inner wall of the lower joint, the sealed cabin being arranged at an axial end of the inner cylinder, and the inner cylinder being connected with the outer cylinder through radially symmetrically distributed connecting parts (513), so as to form an axial extending drilling fluid flow channel (514) between the inner cylinder and the outer cylinder.

2. The counter-torque self-balancing device of claim 1, wherein, the friction mechanism comprises: an annular piston (41) sleeved on the hollow core shaft; and a plurality of friction stators (42) and friction rotors (43) alternately sleeved on the hollow core shaft and located at a lower end of the annular piston. The friction stator is fixedly connected with the inner wall of the shell in the circumferential direction, the friction rotor is fixedly connected with the hollow core shaft in the circumferential direction, the annular piston can move axially downward under the action of hydraulic pressure, so that the friction stator and the friction rotor are tightly fitted, and thus the friction mechanism can generate a friction torque when the shell rotates relative to the hollow core shaft.

3. The counter-torque self-balancing device of claim 2, wherein, A plurality of limiting recesses are arranged on the inner wall of the shell, a plurality of limiting protrusions are arranged on the outer circumferential surface of the friction stator, the limiting protrusions can be fitted into the limiting recesses, so that the friction stator and the shell are fixedly connected in the circumferential direction.

4. The counter-torque self-balancing device of claim 2, wherein, A first involute tooth is arranged on the outer wall of the hollow core shaft, and a second involute tooth is arranged on the inner wall of the friction rotor, the first involute tooth can be fitted with the second involute tooth, so that the friction rotor and the hollow core shaft are fixedly connected in the circumferential direction.

5. The counter-torque self-balancing device of claim 4, wherein, The tooth height of the first involute tooth and the second involute tooth is less than 3 mm.

6. A counter-torque self-balancing device according to any one of claims 2 to 5, wherein, A hydraulic passage (6) is formed on the upper end of the annular piston, the hydraulic passage is in communication with the central flow channel of the hollow core shaft, and the hydraulic passage can transmit the hydraulic pressure in the hollow core shaft to the upper end surface of the annular piston, so that the annular piston generates an axial thrust to tightly fit the friction stator and the friction rotor.

7. The counter-torque self-balancing device of claim 6, wherein, First and second sealing members (411) and (412) are respectively arranged between the annular piston and the hollow core shaft and the shell.

8. The counter-torque self-balancing device of claim 1, wherein, The electrically controlled auxiliary short section further comprises a pressure sensor (59) for measuring the pressure in the drill string.

9. The counter-torque self-balancing device of claim 1, wherein, The hollow core shaft is rotatably connected with the shell through a bearing assembly (7), A step with a downward end face is arranged on the inner wall of the upper joint, and the bearing assembly is arranged between the step and the upper end surface of the shell.

10. The counter-torque self-balancing device of claim 9, wherein, An annular protrusion (31) is arranged on the outer wall of the hollow core shaft, and the bearing assembly is fixedly connected with the hollow core shaft through a fastener (32) and the annular protrusion.

11. The counter-torque automatic balancing device according to claim 9, characterized in that, A drop-preventing ring (8) is further fixedly connected with the lower end of the hollow core shaft.

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