Drill string torque clutch drag reduction tool for directional well drilling and control method of drill string torque clutch drag reduction tool

Abstract

The invention relates to the technical field of petroleum and natural gas, discloses a drill string torque clutch drag reduction tool for directional well drilling and a control method thereof, and solves the problem of directional well drilling backing pressure. The drill string torque clutch drag reduction tool comprises an upper connector, the right end of the upper connector is connected with a piston cylinder through a screw thread, and an inner cavity of the piston cylinder is slidably connected with a piston shaft; the right end of the piston shaft is connected with a middle torque transmission shaft through a screw thread, the right end of the piston cylinder is connected with a T-shaped sleeve through a screw thread, the right end of the T-shaped sleeve is tightly attached to an inner spline shaft, the right end of the middle torque transmission shaft is connected with an outer spline shaft through a screw thread, and a disc spring set is arranged at the right end of the outer spline shaft in an injection mode. A lower joint is tightly attached to the right end of the disc spring group; according to the device, power is provided by drilling fluid and the disc spring set, the size of the provided power is determined by the displacement of the drilling fluid and the pre-tightening degree of the disc spring set, after structural parameters are determined, the required drilling fluid displacement threshold value during conversion of the tool can also be determined, and therefore the control precision is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas technology, specifically a drill string torque clutch drag reduction tool and its control method for directional drilling. Background Technology

[0002] As oil and gas exploration and development advances to deeper, more extended wells, directional drilling technology faces unprecedented challenges. The development mode of ultra-long horizontal sections makes the friction problem between the drill string and the wellbore increasingly prominent—the continuous friction generated during the extension of the drill string not only significantly affects the mechanical drilling rate, but may also cause risks such as abnormal vibration of downhole tools and failure of drilling pressure transmission, which seriously restricts the economical and efficient development of deep resources.

[0003] Current mainstream drag reduction technologies are mainly based on two physical mechanisms: 1. Downhole vibration drag reduction: High-frequency vibration is generated by downhole tools to change the contact form between the drill string and the wellbore, transforming the originally continuous sliding friction into intermittent contact, which theoretically reduces frictional resistance. However, in practical applications, its effective range is limited due to vibration energy attenuation and formation characteristics, and it may negatively impact drill bit life under certain operating conditions; 2. Propulsion pressure drag reduction: Axial force is applied to the drill string using hydraulic or mechanical structures, providing propulsion force to the drill bit, thereby changing the overall motion state of the drill string and achieving drag reduction. Although this technology can alleviate drill string buckling problems to some extent, it requires high stability of the downhole power source, and pressure fluctuations can easily lead to control deviations under complex wellbore trajectories. Currently used tools rarely use the method of converting axial frictional resistance into torsional frictional torque. Therefore, this invention proposes a drill string torque clutch drag reduction tool and its control method for directional drilling to solve the above problems. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the present invention provides a drill string torque clutch drag reduction tool and its control method for directional drilling, which effectively solves the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a drill string torque clutch drag reduction tool for directional drilling, comprising an upper connector, the left end of which is connected to the upper drill string via threads, the right end of which is connected to a piston cylinder via threads, a piston shaft slidably connected to the inner cavity of the piston cylinder, an intermediate torque transmission shaft connected to the right end of the piston shaft via threads, a T-sleeve connected to the right end of the piston cylinder via threads, an internal spline shaft tightly fitted to the right end of the T-sleeve, and a stepped [unclear] connected to the left end of the internal spline shaft via threads. The shaft has an external spline shaft connected to the right end of the intermediate torque transmission shaft via a threaded connection. A single-headed external spline friction cone is slidably connected within the spline groove of the internal spline shaft. Several double-headed external spline friction cones and double-headed internal spline friction cones are alternately arranged between the internal spline shaft and the external spline shaft. The external spline shaft has a step, and a disc spring assembly is tightly fitted to the right end of the step. A lower connector is tightly fitted to the right end of the disc spring assembly. The left end of the lower connector is connected to the internal spline shaft via a threaded connection. The lower connector and the lower drill string are connected via a threaded connection.

[0006] Preferably, the piston cylinder chamber has six oblique holes evenly arranged on the right side to connect the inner and outer spaces, and a sealing ring is detachably connected in the groove at the left end of the piston shaft. The sealing ring is tightly fitted with the piston cylinder outside it, and the intermediate torque transmission shaft is slidably disposed in the spline at the right end of the piston cylinder.

[0007] Preferably, the left end of the external spline shaft step is tightly fitted with the single-headed external spline friction cone. Each double-headed external spline friction cone has several external splines fixed inside, and the external spline shaft has several external spline grooves fixed outside. Each external spline is slidably connected to the external spline groove on its inner side. Each double-headed internal spline friction cone has several internal splines fixed outside, and the internal spline shaft has several internal spline grooves fixed inside. Each internal spline is slidably connected to the internal spline groove on its outer side.

[0008] This invention also provides a control method for a drill string torque clutch drag reduction tool for directional drilling, based on the drill string torque clutch drag reduction tool for directional drilling as described above, comprising the following steps: S1. The computer inputs pre-drilling engineering information, including drill string assembly, drilling parameters and wellbore trajectory, calculates the vibration and friction torque distribution of the drill string in the entire section, preliminarily designs the key parameters of the drag reduction tool in sliding drilling and composite drilling conditions, and transmits them to the central processing computer. S2. The logging instrument is connected to the central processing computer to perform real-time drill string friction torque detection and tool face angle changes, thereby formulating detailed drag reduction schemes, optimizing key parameters of drag reduction tools, and predicting the dynamic analysis, friction torque distribution and tool face angle changes of the drill string under sliding drilling and combined drilling conditions by constructing longitudinal vibration models and torsional vibration models. S3. The central processing computer will transmit the generated drill string drag reduction scheme and optimized key tool parameters to the client computer in real time to guide the drilling site operations under sliding drilling and combined drilling conditions.

[0009] Preferably, the construction of the longitudinal vibration model in S2 is specifically as follows: S21. Discretize the drill string using the lumped mass method and perform mechanical analysis at each lumped mass node. The axial equilibrium equation for the first lumped mass node can be expressed as: ; in, For the quality of the first quality node, and Let be the axial displacements of the first and second mass nodes. For the gravity of the first mass node, The well inclination angle at the first mass node. The change in wellbore inclination angle between the first and second quality nodes can be expressed as: ; P is the hook load, calculated based on the drill bit design drilling pressure. Let be the mud damping coefficient experienced by the first mass block tubing segment. This is the axial frictional force experienced by the first mass node; The equilibrium equation at the i-th lumped mass node can be expressed as: ; Where i = 2,3,4,…,N-1; The equilibrium equation at the Nth lumped mass node, i.e., the drill bit node, can be expressed as: ; in, Let be the instantaneous weight on the drill bit, i.e., the drill pressure, which is the axial force between the drill bit and the rock. Its expression is: ; in, For the displacement of the moving boundary, For the boundary movement speed, It is a function of drill bit weight and rotation speed.

[0010] Preferably, the construction of the torsional vibration model in S2 is specifically as follows: S22. Discretize the drill string using the lumped mass method and perform mechanical analysis at each lumped mass node. The torsional equilibrium equation for the first moment of inertia node can be expressed as: ; in, Let the moment of inertia be the first mass node. , and These are the rotation angle, angular velocity, and angular acceleration of the first node, respectively. and These are the rotation angle and angular velocity of the second node, respectively. Let be the equivalent torsional stiffness of the first mass node. The equivalent torsional damping of the first mass node, The frictional torque at the first mass node; The mechanical equilibrium equation for the i-th lumped mass node can be expressed as: ; in, Let be the moment of inertia of the i-th mass node. , and Let be the rotation angle, angular velocity, and angular acceleration of the i-th node, respectively. Let be the torsional stiffness of the i-th mass node. Let be the torsional damping of the i-th mass node. Let i be the friction torque at this node, i = 2, 3, 4, ..., N-1; The equilibrium equation for the Nth lumped mass node, i.e., the drill bit node, can be expressed as: ; in, The torque applied to the drill bit to the formation rock is related to the drilling pressure, and its mathematical expression is: ; in, Let be the equivalent radius of the drill bit. This is the coefficient of friction between the drill bit and the formation rock.

[0011] Preferably, the construction operations under the two working conditions in S3 specifically include: S31. Under sliding drilling conditions, the entire drag reduction tool moves to the horizontal section of the directional well, the pump is started to circulate the drilling fluid, and the drilling fluid discharge rate is increased. At this time, the piston shaft will drive the intermediate torsion shaft and the external spline shaft to descend and compress the disc spring assembly under the action of the high-pressure drilling fluid. At the same time, the single-head external spline friction cone, the double-head external spline friction cone, and the double-head internal spline friction cone will disengage under the action of the set shims after losing the clamping force, realizing the disengagement process of the entire drag reduction tool and changing the drilling state to sliding drilling. When the drag reduction tool is in the disengaged state, the upper part of the drill string rotates under the action of the top drive or rotary table, converting the axial friction of the drill string into friction torque in the torsional direction, thereby achieving the purpose of drag reduction. S32. Under the combined drilling condition, the drilling fluid discharge rate is reduced. At this time, the thrust provided by the drilling fluid to the piston shaft is insufficient to overcome the preload of the disc spring assembly. The intermediate torsion shaft and the external spline shaft move upward under the thrust of the disc spring assembly, while providing clamping force to the single-head external spline friction cone, the double-head external spline friction cone and the double-head internal spline friction cone, so that they fit tightly together, realizing the entire engagement process of the drag reduction tool, and changing the drilling state to the combined drilling state.

[0012] Preferably, for the drill string dynamics model after adding drag reduction tools, a dynamics model of the tool can be established based on the working principle of the tool, and its working conditions of engagement and disengagement can be analyzed separately.

[0013] Preferably, the dynamic model in the separation state in S31 is as follows: S311. Because the tool is a continuous structure that relies on the outer shell to transmit axial force, the axial force transmission between the tool's upper and lower parts is consistent with that during engagement. ; When the tool is in the disengaged state, the tool and the T-sleeve are separated vertically in the torsional direction. The drill string at the top of the tool rotates, and the drill string at the bottom is no longer affected by the rotation of the upper section of the drill string, so the drilling pressure is transmitted normally.

[0014] Preferably, the dynamic model in the engaged state in S32 is as follows: S321. When the tool is in the engaged state, the drill string rotates as a whole. The tool can be regarded as a section of drill rod, and the drilling state is consistent with ordinary compound drilling. The transmission of force (torque) in both the axial and torsional directions is continuous, that is, in both the axial and torsional directions: ; ; in The axial force transmitted downward by the upper part of the tool. This refers to the axial force transmitted from the upper part to the lower half of the tool. The torque transmitted downwards from the upper part. This refers to the axial force transmitted from the upper part to the lower half of the tool. In the torsional direction, the tool separates at the T-sleeve, but because the sleeve is in contact with the lower outer cylinder, there will be a certain frictional torque on the contact surface. Furthermore, the frictional torque experienced by the T-sleeve and the lower outer cylinder is opposite, i.e. ; ; ; in This refers to the torque experienced by the upper part of the T-sleeve. The torque experienced by the lower sleeve. The frictional torque experienced by the two surfaces in contact is [value missing]. The coefficient of friction of the material. The average contact radius can be expressed as: .

[0015] Compared with the prior art, the beneficial effects of the present invention are: (1) This device is powered by drilling fluid and disc spring assembly. The amount of power it provides is determined by the flow rate of drilling fluid and the preload of disc spring assembly. After the structural parameters are determined, the threshold of drilling fluid flow rate required when this tool is switched will also be determined. Thus, the power can be changed by controlling the flow rate of drilling fluid, thereby ensuring control accuracy. (2) This device can achieve the drag reduction effect in sliding drilling mode and provide stable drilling pressure for the drill bit; this device utilizes the characteristics of friction clutch to achieve flexible switching between engagement and disengagement, reduce the impact generated during engagement, and avoid the problem of centering difficulties, and can meet the requirements of the drill string to transmit torque; this device can achieve flexible switching between sliding drilling and composite drilling modes, so as to stabilize the drilling working state. (3) This device is driven by drilling fluid, and the control is simple and reliable. The present invention is a pure mechanical structure, which can adapt to the harsh working conditions of drilling, with a low failure rate and safety and reliability, thereby further ensuring the test effect. The T-shaped sleeve 7 and the piston cylinder 2 are used to lock the stepped shaft 6. The stepped shaft 6 is used to position the inner spline shaft, and then the lower joint is positioned by the inner spline shaft, which makes the disassembly of the entire tool simple and improves the installation efficiency, thereby saving time. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0017] In the attached diagram: Figure 1This is a schematic diagram of the overall device; Figure 2 This is a schematic diagram of the piston cylinder of this device; Figure 3 This is a schematic diagram of the double-headed internal spline friction cone of this device; Figure 4 This is a schematic diagram of the double-headed external spline friction cone of this device; Figure 5 This is a schematic diagram of the axial force analysis of the drill string mass node in this device; Figure 6 This is a schematic diagram of the torsional stress analysis of the drill string mass nodes in this device; Figure 7 This is a schematic diagram of the drill string coupling of this device; Figure 8 This is a schematic diagram of the frictional force model between the drill string and the well wall in this device; Figure 9 This is a schematic diagram of the frictional force decomposition when the drill string mass node of this device is at rest; Figure 10 This is a schematic diagram showing the decomposition of frictional forces during the movement of the drill string mass nodes in this device.

[0018] In the diagram: 1-Upper connector; 2-Piston cylinder; 3-Sealing ring; 4-Piston shaft; 5-Intermediate torque transmission shaft; 6-Stepped shaft; 7-T-sleeve; 8-Internal spline shaft; 9-Single-head external spline friction cone; 10-Double-head external spline friction cone; 11-Double-head internal spline friction cone; 12-External spline shaft; 13-Disc spring assembly; 14-Lower connector; 15-External spline; 16-Internal spline; 17-Slanted hole. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Example 1, by Figures 1-10This invention discloses a drill string torque clutch drag reduction tool for directional drilling, comprising an upper connector 1 made of alloy material, which connects the upper drill string and the entire tool. The left end of the upper connector 1 is threadedly connected to the upper drill string, and the right end of the upper connector 1 is threadedly connected to a piston cylinder 2 for positioning a piston shaft 4. The piston shaft 4 is slidably connected to the inner cavity of the piston cylinder 2. The right end of the piston shaft 4 is threadedly connected to an intermediate torque transmission shaft 5 for transmitting power. The right end of the piston cylinder 2 is threadedly connected to a T-shaped sleeve 7 made of alloy material, which, in conjunction with the piston cylinder 2, locks a stepped shaft 6. The right end of the T-shaped sleeve 7 is tightly fitted with an internal spline shaft 8 for positioning a single-headed external spline friction cone 9. The left end of the internal spline shaft 8 is also threadedly connected to the stepped shaft 6. The internal spline shaft 8 is used for positioning. The right end of the intermediate torque transmission shaft 5 is connected to an external spline shaft 12 via a threaded connection. The external spline shaft 12 and the internal spline shaft 8 are used to position the external spline friction cone 10 and the double-headed internal spline friction cone 11. A single-headed external spline friction cone 9 is slidably connected within the spline groove of the internal spline shaft 8. The single-headed external spline friction cone 9 ensures the stability of the external spline friction cone 10 and the double-headed internal spline friction cone 11. A plurality of double-headed external spline friction cones 10 and double-headed internal spline friction cones 11 are alternately arranged between the key shaft 8 and the external spline shaft 12. The external spline shaft 12 is provided with a step. A disc spring assembly 13 is tightly fitted to the right end of the step of the external spline shaft 12. The disc spring assembly 13 is used to provide power. A lower connector 14 is tightly fitted to the right end of the disc spring assembly 13. The left end of the lower connector 14 is connected to the internal spline shaft 8 by a thread. The lower connector 14 and the lower drill string are connected by a thread.

[0021] Beneficially, the piston cylinder 2 has six oblique holes 17 evenly arranged on the right side of the chamber to connect the inner and outer spaces. A sealing ring 3 is detachably connected in the groove at the left end of the piston shaft 4. The sealing ring 3 is made of rubber material. The sealing ring 3 can ensure the sealing of the piston shaft 4 and the piston cylinder 2. The sealing ring 3 fits tightly with the piston cylinder 2 outside it. The intermediate torsion transmission shaft 5 is slidably arranged in the spline at the right end of the piston cylinder 2.

[0022] Beneficially, the left end of the step of the external spline shaft 12 is tightly fitted with the single-headed external spline friction cone 9. Each double-headed external spline friction cone 10 has several external splines 15 fixed inside, and the external spline shaft 12 has several external spline grooves fixed outside. Each external spline 15 is slidably connected to the external spline groove on its inner side. Each double-headed internal spline friction cone 11 has several internal splines 16 fixed outside, and the internal spline shaft 8 has several internal spline grooves fixed inside. Each internal spline 16 is slidably connected to the internal spline groove on its outer side.

[0023] This embodiment provides a control method for a drill string torque clutch drag reduction tool for directional drilling, based on the aforementioned drill string torque clutch drag reduction tool for directional drilling, including the following steps: S1. The computer inputs pre-drilling engineering information, including drill string assembly, drilling parameters and wellbore trajectory, calculates the vibration and friction torque distribution of the drill string in the entire section, preliminarily designs the key parameters of the drag reduction tool in sliding drilling and composite drilling conditions, and transmits them to the central processing computer. S2. The logging instrument is connected to the central processing computer to perform real-time drill string friction torque detection and tool face angle changes, thereby formulating detailed drag reduction schemes, optimizing key parameters of drag reduction tools, and predicting the dynamic analysis, friction torque distribution and tool face angle changes of the drill string under sliding drilling and combined drilling conditions by constructing longitudinal vibration models and torsional vibration models. S3. The central processing computer will transmit the generated drill string drag reduction scheme and optimized key tool parameters to the client computer in real time to guide the drilling site operations under sliding drilling and combined drilling conditions.

[0024] Beneficially, the construction of the longitudinal vibration model in S2 is specifically as follows: S21. Discretize the drill string using the lumped mass method and perform mechanical analysis at each lumped mass node. The axial equilibrium equation for the first lumped mass node can be expressed as: ; in, For the quality of the first quality node, and Let be the axial displacements of the first and second mass nodes. For the gravity of the first mass node, The well inclination angle at the first mass node. The change in wellbore inclination angle between the first and second quality nodes can be expressed as: ; P is the hook load, calculated based on the drill bit design drilling pressure. Let be the mud damping coefficient experienced by the first mass block tubing segment. This is the axial frictional force experienced by the first mass node; The equilibrium equation at the i-th lumped mass node can be expressed as: ; Where i = 2,3,4,…,N-1; The equilibrium equation at the Nth lumped mass node, i.e., the drill bit node, can be expressed as: ; in, Let be the instantaneous weight on the drill bit, i.e., the drill pressure, which is the axial force between the drill bit and the rock. Its expression is: ; in, For the displacement of the moving boundary, For the boundary movement speed, It is a function of drill bit weight and rotational speed; Beneficially, for ease of calculation, the equilibrium equations corresponding to these drill string mass nodes can be represented using matrix equations, the expressions of which are: ; in, The system's quality matrix, Here is the damping matrix. Let F be the stiffness matrix and F be the external force vector. , , These represent the displacement, velocity, and acceleration of each node, respectively. The axial vibration mass matrix can be represented as: ; The tool is coupled into the drill string model by simplifying it into two nodes of the original model. That is, the upper piston cylinder and internal components are coupled to the upper connector as one node, and the internal spline shaft and internal components are coupled to the lower connector as one node. Since the main function of the tool is to affect the torsional direction of operation and has little effect on the axial direction, the original model is still applicable to the dynamic model after the tool is added. The axial vibration stiffness matrix can be expressed as: ; The damping matrix of an axially vibrating structure can be expressed as: ; The drilling fluid damping effect can be expressed as: ; The external force vector of axial vibration can be expressed as: ; The displacement, velocity, and acceleration vectors can be represented as follows: ; ; .

[0025] Beneficially, the construction of the torsional vibration model in S2 is specifically as follows: S22. Discretize the drill string using the lumped mass method and perform mechanical analysis at each lumped mass node. The torsional equilibrium equation for the first moment of inertia node can be expressed as: ; in, Let the moment of inertia be the first mass node. , and These are the rotation angle, angular velocity, and angular acceleration of the first node, respectively. and These are the rotation angle and angular velocity of the second node, respectively. Let be the equivalent torsional stiffness of the first mass node. The equivalent torsional damping of the first mass node, The frictional torque at the first mass node; The mechanical equilibrium equation for the i-th lumped mass node can be expressed as: ; in, Let be the moment of inertia of the i-th mass node. , and Let be the rotation angle, angular velocity, and angular acceleration of the i-th node, respectively. Let be the torsional stiffness of the i-th mass node. Let be the torsional damping of the i-th mass node. Let i be the friction torque at this node, i = 2, 3, 4, ..., N-1; The equilibrium equation for the Nth lumped mass node, i.e., the drill bit node, can be expressed as: ; in, The torque applied to the drill bit to the formation rock is related to the drilling pressure, and its mathematical expression is: ; in, Let be the equivalent radius of the drill bit. The coefficient of friction between the drill bit and the formation rock; Beneficially, the above equilibrium equations can be rearranged into the following matrix form: ; in, Here is the rotational inertia matrix. For the torsional damping matrix, Let T be the torsional stiffness matrix, and T be the torsional load vector. , , These represent the rotational angular displacement, angular velocity, and angular acceleration of each node in the drill string.

[0026] The moment of inertia matrix of the drill string is: ; The torsional stiffness matrix of the drill string is: ; The torsional damping matrix of the drill string is: ; Since the rotational speed of the first mass node is a fixed value and does not change with time, therefore, the stiffness matrix... and damping matrix The first row contains all 0 elements; The torsional load vector of the drill string is: .

[0027] Beneficially, the construction operations under the two working conditions in S3 specifically include: S31. Under sliding drilling conditions, the entire drag reduction tool moves to the horizontal section of the directional well, the pump is started to circulate the drilling fluid, and the drilling fluid discharge rate is increased. At this time, the piston shaft 4 will drive the intermediate torsion shaft 5 and the external spline shaft 12 to descend and compress the disc spring assembly 13 under the action of the high-pressure drilling fluid. At the same time, the single-head external spline friction cone 9, the double-head external spline friction cone 10 and the double-head internal spline friction cone 11 will disengage under the action of the set shims after losing the clamping force, realizing the disengagement process of the entire drag reduction tool and changing the drilling state to sliding drilling. When the drag reduction tool is in the disengaged state, the upper part of the drill string rotates under the action of the top drive or rotary table, converting the axial friction of the drill string into friction torque in the torsional direction, thereby achieving the purpose of drag reduction. S32. Under the combined drilling condition, the drilling fluid discharge rate is reduced. At this time, the thrust provided by the drilling fluid to the piston shaft 4 is insufficient to overcome the preload of the disc spring assembly 13. The intermediate torsion shaft 5 and the external spline shaft 12 move upward under the thrust of the disc spring assembly 13, and at the same time provide clamping force to the single-head external spline friction cone 9, the double-head external spline friction cone 10 and the double-head internal spline friction cone 11, so that they fit tightly together, realize the entire engagement process of the drag reduction tool, and change the drilling state to the combined drilling state.

[0028] Beneficially, for the drill string dynamics model after adding drag-reducing tools, a dynamic model of the tool can be established based on the working principle of the tool, and its working conditions of engagement and disengagement can be analyzed separately.

[0029] Beneficially, the dynamic model in the separated state of S31 is as follows: S311. Because the tool is a continuous structure that relies on the outer shell to transmit axial force, the axial force transmission between the tool's upper and lower parts is consistent with that during engagement. ; When the tool is in the disengaged state, the tool and the T-sleeve are separated vertically in the torsional direction. The drill string at the top of the tool rotates, and the drill string at the bottom is no longer affected by the rotation of the upper section of the drill string, so the drilling pressure is transmitted normally.

[0030] Beneficially, the dynamic model of the engaged state in S32 is as follows: S321. When the tool is in the engaged state, the drill string rotates as a whole. The tool can be regarded as a section of drill rod, and the drilling state is consistent with ordinary compound drilling. The transmission of force (torque) in both the axial and torsional directions is continuous, that is, in both the axial and torsional directions: ; ; in The axial force transmitted downward by the upper part of the tool. This refers to the axial force transmitted from the upper part to the lower half of the tool. The torque transmitted downwards from the upper part. This refers to the axial force transmitted from the upper part to the lower half of the tool. In the torsional direction, the tool separates at the T-sleeve, but because the sleeve is in contact with the lower outer cylinder, there will be a certain frictional torque on the contact surface. Furthermore, the frictional torque experienced by the T-sleeve and the lower outer cylinder is opposite, i.e. ; ; ; in This refers to the torque experienced by the upper part of the T-sleeve. The torque experienced by the lower sleeve. The frictional torque experienced by the two surfaces in contact is [value missing]. The coefficient of friction of the material. The average contact radius can be expressed as: ; Beneficially, by segmenting the calculation process, the torsional equivalent stiffness matrix above and below the tool can be expressed as: ; ; in, This is the equivalent stiffness matrix of the drill string above the T-sleeve. The equivalent stiffness of the previous mass node is applied to the tool. The equivalent stiffness at the tool location above the T-sleeve. This is the equivalent stiffness matrix of the drill string below the T-sleeve. This represents the equivalent stiffness at the tooling location below the T-sleeve. The equivalent stiffness of a mass node after tool installation, and the equivalent damping matrix of the drill string during calculation, can be expressed as: ; ; in, This is the equivalent stiffness matrix of the drill string above the T-sleeve. The equivalent stiffness of the previous mass node is applied to the tool. The equivalent stiffness at the tool location above the T-sleeve. This is the equivalent stiffness matrix of the drill string below the T-sleeve. This represents the equivalent stiffness at the tooling location below the T-sleeve. The equivalent stiffness of a mass node after the tool is installed.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A drill string torque clutch drag reduction tool for directional drilling, characterized in that: The system includes an upper connector (1), the left end of which is connected to the upper drill string via a threaded connection. The right end of the upper connector (1) is connected to a piston cylinder (2) via a threaded connection. A piston shaft (4) is slidably connected to the inner cavity of the piston cylinder (2). The right end of the piston shaft (4) is connected to an intermediate torque transmission shaft (5) via a threaded connection. The right end of the piston cylinder (2) is connected to a T-shaped sleeve (7) via a threaded connection. An internal spline shaft (8) is tightly fitted to the right end of the T-shaped sleeve (7). The left end of the internal spline shaft (8) is also connected to a stepped shaft (6) via a threaded connection. The right end of the intermediate torque transmission shaft (5) is connected to an external spline shaft (12) via a threaded connection. The inner spline shaft (8) is slidably connected to a single-headed external spline friction cone (9) in the spline groove. Several double-headed external spline friction cones (10) and double-headed inner spline friction cones (11) are alternately arranged between the inner spline shaft (8) and the outer spline shaft (12). The outer spline shaft (12) is provided with a step. The right end of the step of the outer spline shaft (12) is tightly fitted with a disc spring assembly (13). The right end of the disc spring assembly (13) is tightly fitted with a lower connector (14). The left end of the lower connector (14) is connected to the inner spline shaft (8) by a thread. The lower connector (14) and the lower drill string are connected by a thread.

2. The drill string torque clutch drag reduction tool for directional drilling according to claim 1, characterized in that: The piston cylinder (2) has six oblique holes (17) evenly arranged on the right side of the chamber to connect the inner and outer spaces. A sealing ring (3) is detachably connected in the groove at the left end of the piston shaft (4). The sealing ring (3) is tightly fitted to the piston cylinder (2) outside it. The intermediate torsion shaft (5) is slidably arranged in the spline at the right end of the piston cylinder (2).

3. The drill string torque clutch drag reduction tool for directional drilling according to claim 2, characterized in that: The left end of the step of the external spline shaft (12) is closely fitted with the single-head external spline friction cone (9). Each double-head external spline friction cone (10) has several external splines (15) fixed inside. The external spline shaft (12) has several external spline grooves fixed outside. Each external spline (15) is slidably connected to the external spline groove on its inner side. Each double-head internal spline friction cone (11) has several internal splines (16) fixed outside. The internal spline shaft (8) has several internal spline grooves fixed inside. Each internal spline (16) is slidably connected to the internal spline groove on its outer side.

4. A control method for a drill string torque clutch drag reduction tool for directional drilling, based on the drill string torque clutch drag reduction tool for directional drilling as described in claim 9, characterized in that: Includes the following steps: S1. The computer inputs pre-drilling engineering information, including drill string assembly, drilling parameters and wellbore trajectory, calculates the vibration and friction torque distribution of the drill string in the entire section, preliminarily designs the key parameters of the drag reduction tool in sliding drilling and composite drilling conditions, and transmits them to the central processing computer. S2. The logging instrument is connected to the central processing computer to perform real-time drill string friction torque detection and tool face angle changes, thereby formulating detailed drag reduction schemes, optimizing key parameters of drag reduction tools, and predicting the dynamic analysis, friction torque distribution and tool face angle changes of the drill string under sliding drilling and combined drilling conditions by constructing longitudinal vibration models and torsional vibration models. S3. The central processing computer will transmit the generated drill string drag reduction scheme and optimized key tool parameters to the client computer in real time to guide the drilling site operations under sliding drilling and combined drilling conditions.

5. The control method for a drill string torque clutch drag reduction tool for directional drilling according to claim 4, characterized in that: The construction of the longitudinal vibration model in S2 is as follows: S21. Discretize the drill string using the lumped mass method and perform mechanical analysis at each lumped mass node. The axial equilibrium equation for the first lumped mass node can be expressed as: ； in, For the quality of the first quality node, and Let be the axial displacements of the first and second mass nodes. Let g be the gravity at the first mass node. The well inclination angle at the first mass node. The change in wellbore inclination angle between the first and second quality nodes can be expressed as: ； P is the hook load, calculated based on the drill bit design drilling pressure. Let be the mud damping coefficient experienced by the first mass block tubing segment. This is the axial frictional force experienced by the first mass node; The equilibrium equation at the i-th lumped mass node can be expressed as: ; Where i = 2,3,4,…,N-1; The equilibrium equation at the Nth lumped mass node, i.e., the drill bit node, can be expressed as: ; in, Let be the instantaneous weight on the drill bit, i.e., the drill pressure, which is the axial force between the drill bit and the rock. Its expression is: ; in, For the displacement of the moving boundary, For the boundary movement speed, It is a function of drill bit weight and rotation speed.

6. The control method for a drill string torque clutch drag reduction tool for directional drilling according to claim 5, characterized in that: The torsional vibration model in S2 is constructed as follows: S22. Discretize the drill string using the lumped mass method and perform mechanical analysis at each lumped mass node. The torsional equilibrium equation for the first moment of inertia node can be expressed as: ; in, Let the moment of inertia be the first mass node. , and These are the rotation angle, angular velocity, and angular acceleration of the first node, respectively. and These are the rotation angle and angular velocity of the second node, respectively. Let be the equivalent torsional stiffness of the first mass node. The equivalent torsional damping of the first mass node, The frictional torque at the first mass node; The mechanical equilibrium equation for the i-th lumped mass node can be expressed as: ； in, Let be the moment of inertia of the i-th mass node. , and Let be the rotation angle, angular velocity, and angular acceleration of the i-th node, respectively. Let be the torsional stiffness of the i-th mass node. Let be the torsional damping of the i-th mass node. Let i be the friction torque at this node, i = 2, 3, 4, ..., N-1; The equilibrium equation for the Nth lumped mass node, i.e., the drill bit node, can be expressed as: ； in, The torque applied to the drill bit to the formation rock is related to the drilling pressure, and its mathematical expression is: ； in, Let be the equivalent radius of the drill bit. This is the coefficient of friction between the drill bit and the formation rock.

7. The control method for a drill string torque clutch drag reduction tool for directional drilling according to claim 6, characterized in that: The specific construction operations under the two working conditions in S3 include: S31. Under sliding drilling conditions, the entire drag reduction tool moves to the horizontal section of the directional well, the pump is turned on to circulate the drilling fluid, and the drilling fluid discharge rate is increased. At this time, the piston shaft (4) will drive the intermediate transmission shaft (5) and the external spline shaft (12) to descend and compress the disc spring assembly (13) under the action of the high pressure drilling fluid. At the same time, the single-head external spline friction cone (9), the double-head external spline friction cone (10) and the double-head internal spline friction cone (11) will disengage under the action of the set shims after losing the clamping force, realizing the process of disengaging the entire drag reduction tool and changing the drilling state to sliding drilling. When the drag reduction tool is in the disengaged state, the upper part of the drill string rotates under the action of the top drive or the rotary table, converting the axial friction of the drill string into friction torque in the torsional direction, thus achieving the purpose of drag reduction. S32. Under the combined drilling condition, the drilling fluid discharge rate is reduced. At this time, the thrust provided by the drilling fluid to the piston shaft (4) is insufficient to overcome the preload of the disc spring assembly (13). The intermediate torsion shaft (5) and the external spline shaft (12) move upward under the thrust of the disc spring assembly (13), while providing clamping force to the single-head external spline friction cone (9), the double-head external spline friction cone (10) and the double-head internal spline friction cone (11), so that they fit tightly together, realize the entire drag reduction tool engagement process, and change the drilling state to the combined drilling state.

8. The control method for a drill string torque clutch drag reduction tool for directional drilling according to claim 7, characterized in that: For the drill string dynamics model after adding drag reduction tools, a dynamic model of the tool can be established based on the working principle of the tool, and its working conditions of engagement and disengagement can be analyzed separately.

9. The control method for a drill string torque clutch drag reduction tool for directional drilling according to claim 8, characterized in that: The specific dynamic model in the separated state of S31 is as follows: S311. Because the tool is a continuous structure that relies on the outer shell to transmit axial force, the axial force transmission between the tool's upper and lower parts is consistent with that during engagement. ； When the tool is in the disengaged state, the tool and the T-sleeve are separated vertically in the torsional direction. The drill string at the top of the tool rotates, and the drill string at the bottom is no longer affected by the rotation of the upper section of the drill string, so the drilling pressure is transmitted normally.

10. The control method for a drill string torque clutch drag reduction tool for directional drilling according to claim 9, characterized in that: The specific dynamic model of S32 in the engaged state is as follows: S321. When the tool is in the engaged state, the drill string rotates as a whole. The tool can be regarded as a section of drill rod, and the drilling state is consistent with ordinary compound drilling. The transmission of force (torque) in both the axial and torsional directions is continuous, that is, in both the axial and torsional directions: ； ； in The axial force transmitted downward by the upper part of the tool. This refers to the axial force transmitted from the upper part to the lower half of the tool. The torque transmitted downwards from the upper part. This refers to the axial force transmitted from the upper part to the lower half of the tool. In the torsional direction, the tool separates at the T-sleeve, but because the sleeve is in contact with the lower outer cylinder, there will be a certain frictional torque on the contact surface. Furthermore, the frictional torque experienced by the T-sleeve and the lower outer cylinder is opposite, i.e. ； ； ； in This refers to the torque experienced by the upper part of the T-sleeve. The torque experienced by the lower sleeve. The frictional torque experienced by the two surfaces in contact is [value missing]. The coefficient of friction of the material. The average contact radius can be expressed as: 。

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