A drill pipe joint with torsional resistance and a design method for drill pipe joints

Abstract

The present application provides a torsion-resistant drill pipe joint and a design method thereof. The drill pipe joint includes a male joint and a female joint. The outer surface of the male joint and the inner surface of the female joint are respectively a first conical connection surface and a second conical connection surface. External threads and internal threads are provided on the first conical connection surface and the second conical connection surface. The male joint and its matching female joint, as well as the female joint and its matching male joint, respectively correspond to a type of thread connection. Each type of thread connection has a set range of make-up turns and torsional strength. The set range of make-up turns is 5 to 13 turns, and the set range of torsional strength is not less than 10,000 ft-lbs. Through the coaxial conical connection surface design, combined with the precisely set make-up turns and torsional strength range, the joint structure and mechanical properties are optimized to ensure that under complex and harsh drilling conditions, the drill pipe joint can efficiently, stably and safely transmit torque, reduce the failure rate, and improve the overall drilling operation efficiency.

Description

Technical Field

[0001] The invention relates to the field of drilling tools, and in particular to a torsion-resistant drill pipe joint and a drill pipe joint design method. Background Art

[0002] In the field of exploration and exploitation of resources such as oil and natural gas, drill pipe, as a key component of the drilling system, undertakes important missions such as transmitting torque, conveying drilling fluid and supporting the weight of drill tools. The performance of its joints is directly related to the safety, efficiency and cost control of the entire drilling operation.

[0003] Traditional drill pipe joint designs have gradually exposed many limitations when dealing with complex and changeable downhole working conditions. On the one hand, early drill pipe joints often used simple cone connections with threaded structures. This connection method has significant stress concentration when subjected to high torque.

[0004] As drilling technology expands to deeper and more complex geological structures, stringent requirements are placed on the torsional performance of drill pipe joints. The complex geological environment underground, such as the high resistance brought by hard rock formations and the irregular stress caused by formation creep applied to the drill pipe, all test the torsional stability of the joints. Today, the torsional strength of conventional drill pipe joints is often difficult to match the growing operational needs. A large number of joints fail because they cannot withstand torque before reaching the expected drilling depth, which not only causes the loss of equipment such as drill pipes, but also wastes a lot of manpower and material resources due to frequent replacement of joints during drilling.

[0005] Furthermore, the make-up speed accounts for a large proportion of the non-working time during the tripping and drilling process of the drilling platform. Therefore, studying the relationship between the various parameters of the thread structure and the make-up speed is of great significance to improving the working efficiency of the drilling platform and reducing the non-working time (NPT). If the number of make-up turns is too small, the thread engagement between the joints is insufficient, and it is very easy to loosen and disengage under the action of torque, causing drilling safety accidents; and if the number of make-up turns is too large, the non-working time (NPT) is increased, thus affecting the working efficiency.

[0006] In addition, during the long-term rotation and vibration of the drill pipe, even small connection defects or performance shortcomings will accumulate and magnify over time. If the thread types of different drill pipe joints do not have standardized and suitable threading circles and torsional strength ranges, it will aggravate the wear of the connection parts, seal failure and other problems, leading to drilling fluid leakage, affecting the normal operation of the drilling fluid circulation system, and further endangering the stability and safety of downhole operations. Summary of the invention

[0007] The object of the present invention is to provide a torsional-resistant drill pipe joint and a design method for drill pipe joints. By studying the relationship between various parameters of the thread structure and the make-up speed, it is possible to reduce the non-productive time (NPT) and improve the working efficiency of the drilling platform. At the same time, the drill pipe joint also has good torsional strength.

[0008] The embodiments of the present invention are implemented as follows:

[0009] In a first aspect, a torsional-resistant drill pipe joint according to an embodiment of the present application includes a male joint and a female joint respectively disposed at both ends of the drill pipe. The male joint and the female joint are coaxially arranged. The outer surface of the male joint and the inner surface of the female joint are a first tapered connection surface and a second tapered connection surface respectively, and the slopes of the first tapered connection surface and the second tapered connection surface are the same; an external thread and an internal thread are respectively provided on the first tapered connection surface and the second tapered connection surface. The external thread is used for threaded connection with the second tapered connection surface of the female joint of the first drill pipe that matches it, and the internal thread is used for threaded connection with the first tapered connection surface of the male joint of the second drill pipe that matches it;

[0010] The male joint and the corresponding female joint, as well as the female joint and the corresponding male joint, correspond to a type of thread. Each type of thread is determined by the thread parameters of the male joint and the corresponding female joint. Each type of thread has a set range of make-up turns and a set range of torsional strength. The set range of the make-up turns is 5 turns - 13 turns, and the set range of the torsional strength is not less than 10000 ft-lbs; the make-up turns and the thread parameters also satisfy the following relationship:

[0011] ;

[0012] In the formula, N is the make-up turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc.

[0013] In a possible implementation manner, the thread parameters of the male joint and the female joint include the radius of the root arc. The range of the radius of the root arc of each male joint and female joint in any type of thread is 0.038 in - 0.08 in.

[0014] In a possible implementation manner, the thread parameters of the male joint and the female joint further include the half angle of the thread profile. The range of the half angle of the thread profile of each male joint and female joint in any type of thread is 27.5° - 44.5°.

[0015] In a possible embodiment, the thread parameters of the male connector and the female connector further include a taper, and the taper of each of the male connector and the female connector in any thread type ranges from 1 / 16 to 1 / 6.

[0016] In a possible embodiment, when the thread type is a designed thread type, the taper and the root radius of the thread also satisfy the following corresponding relationship. When the taper is 1 / 16, the corresponding root radius of the thread ranges from 0.05 in to 0.065 in; when the taper is 1 / 12, the corresponding root radius of the thread ranges from 0.04 in to 0.060 in; when the taper is 1 / 10, the corresponding root radius of the thread ranges from 0.045 in to 0.055 in.

[0017] In a possible embodiment, the thread parameters of the male connector and the female connector further include a pitch, and the pitch of each of the male connector and the female connector in any thread type ranges from 0.250 in to 0.364 in.

[0018] In a possible embodiment, the partial derivative of the number of turns for making up the thread and the taper satisfies the following relational expression:

[0019] ;

[0020] In the formula, N is the number of turns for making up the thread, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the root radius of the thread.

[0021] In a possible embodiment, the partial derivative of the number of turns for making up the thread and the root radius of the thread satisfies the following relational expression:

[0022] ;

[0023] In the formula, N is the number of turns for making up the thread, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the root radius of the thread.

[0024] In a possible embodiment, the partial derivative of the number of turns for making up the thread and the pitch satisfies the following relational expression:

[0025] ;

[0026] In the formula, N is the number of turns for making up the thread, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the root radius of the thread.

[0027] In a possible embodiment, the root radius of the thread, the pitch, the half angle of the thread profile, and the taper satisfy the following relational expression:

[0028] ;

[0029] Wherein, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, R is the radius of the root arc of the thread, and Rmax is the maximum value of the radius of the root arc of the thread.

[0030] In a second aspect, a torsional resistance drill pipe joint according to an embodiment of the present application includes a male joint and a female joint respectively arranged at both ends of the drill pipe. The male joint and the female joint are coaxially arranged. The outer surface of the male joint and the inner surface of the female joint are respectively a first tapered connection surface and a second tapered connection surface, and the slopes of the first tapered connection surface and the second tapered connection surface are the same; external threads and internal threads are respectively arranged on the first tapered connection surface and the second tapered connection surface. The external threads are used for threaded connection with the second tapered connection surface of the female joint of the first drill pipe that matches it, and the internal threads are used for threaded connection with the first tapered connection surface of the male joint of the second drill pipe that matches it;

[0031] The male joint and the female joint that match it, and the female joint and the male joint that match it respectively correspond to a thread type. Each thread type has a set range of make-up turns. Each thread type is determined by the thread parameters of the male joint and the female joint. The thread parameters of the male joint and the female joint include the radius of the root arc of the thread, the half angle of the thread profile, the taper, and the pitch; the make-up turns satisfy the following relational expression with the radius of the root arc of the thread, the half angle of the thread profile, the taper, and the pitch:

[0032] ;

[0033] Wherein, N is the make-up turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc of the thread.

[0034] In a possible implementation manner, the partial derivative of the make-up turns with respect to the taper satisfies the following relational expression:

[0035] ;

[0036] Wherein, N is the make-up turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc of the thread.

[0037] In a possible implementation manner, the partial derivative of the make-up turns with respect to the radius of the root arc of the thread satisfies the following relational expression:

[0038] ;

[0039] Wherein, N is the make-up turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc of the thread.

[0040] In a possible implementation manner, the partial derivative of the make-up turns with respect to the pitch satisfies the following relational expression:

[0041] ;

[0042] Wherein, N is the number of make-up turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc.

[0043] In a possible embodiment, the radius of the root arc, the pitch, the half angle of the thread profile, and the taper satisfy the following relationship:

[0044] ;

[0045] Wherein, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, R is the radius of the root arc, and Rmax is the maximum value of the radius of the root arc.

[0046] In a possible embodiment, each of the connection types has a set range of the number of make-up turns and a set range of torsional strength. The set range of the number of make-up turns is 5 turns - 13 turns, and the set range of the torsional strength is not less than 10,000 ft-lbs.

[0047] In a possible embodiment, the range of the radius of the root arc of each of the male connector and the female connector in any connection type is 0.038 in - 0.08 in.

[0048] In a possible embodiment, the range of the half angle of the thread profile of each of the male connector and the female connector in any connection type is 27.5° - 44.5°.

[0049] In a possible embodiment, the range of the taper of each of the male connector and the female connector in any connection type is 1 / 16 - 1 / 6.

[0050] In a possible embodiment, when the connection type is the designed connection type, the taper and the radius of the root arc also satisfy the following corresponding relationship. When the taper is 1 / 16, the corresponding range of the radius of the root arc is 0.05 in to 0.065 in; when the taper is 1 / 12, the corresponding range of the radius of the root arc is 0.04 in to 0.060 in; when the taper is 1 / 10, the corresponding range of the radius of the root arc is 0.045 in to 0.055 in.

[0051] In a possible embodiment, the range of the pitch of each of the male connector and the female connector in any connection type is 0.250 in - 0.364 in.

[0052] In a third aspect, a method for designing a drill pipe joint according to an embodiment of the present application includes:

[0053] Determine the setting ranges of the make-up turns and torsional strength of the designed thread type according to the make-up turns and torsional strength of the standard thread type and special thread type respectively; wherein, the setting range corresponding to the make-up turns of the designed thread type is 5 to 13 turns, and the setting range corresponding to the torsional strength of the designed thread type is not less than 10,000 ft-lbs;

[0054] Set the thread parameters in the designed thread type, where the thread parameters include the root radius, taper, thread profile half angle, and pitch, and select the root radius and pitch according to the ranges of the make-up turns and torsional strength;

[0055] Select the taper range of the series according to the ranges of the make-up turns and torsional strength;

[0056] According to the relational formula between the thread parameters and the make-up turns, obtain the series range of the root radius corresponding to the taper range.

[0057] In a possible implementation, the make-up turns, the root radius, the thread profile half angle, the taper, and the pitch satisfy the following relational formula:

[0058] ;

[0059] In the formula, N is the make-up turns, θ is the thread profile half angle, tpr is the taper, P is the pitch, and R is the root radius.

[0060] In a possible implementation, the taper and the root radius also satisfy the following corresponding relationship. When the taper is 1 / 16, the corresponding root radius range is 0.05 in to 0.065 in; when the taper is 1 / 12, the corresponding root radius range is 0.04 in to 0.060 in; when the taper is 1 / 10, the corresponding root radius range is 0.045 in to 0.055 in.

[0061] The beneficial effects of the embodiments of the present invention are as follows: Through the unique coaxial conical connection surface design, combined with the precisely set make-up turns (5 - 13 turns) and the torsional strength range not less than 10,000 ft-lbs, the present invention optimizes the joint structure and mechanical properties, ensuring that the drill pipe joint can efficiently, stably, and safely transmit torque under complex and harsh drilling conditions, reducing the failure rate, and improving the overall drilling operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can be obtained based on these drawings.

[0063] Figure 1 It is a sectional view of the male joint of a torsional drill pipe joint along the axial direction in an embodiment of the present invention;

[0064] Figure 2 It is a sectional view of the female joint of a torsional drill pipe joint along the axial direction in an embodiment of the present invention;

[0065] Figure 3 It is a relationship diagram between the number of screwing-on turns and the half angle of the tooth profile of a torsional drill pipe joint in an embodiment of the present invention;

[0066] Figure 4 It is a relationship diagram between the number of screwing-on turns and the taper of a torsional drill pipe joint in an embodiment of the present invention;

[0067] Figure 5 It is a relationship diagram between the number of screwing-on turns and the radius of the tooth root arc of a torsional drill pipe joint in an embodiment of the present invention;

[0068] Figure 6 It is a relationship diagram between the number of screwing-on turns and the pitch of a torsional drill pipe joint in an embodiment of the present invention;

[0069] Figure 7 It is a relationship diagram between the number of screwing-on turns and the taper and the radius of the tooth root arc of a torsional drill pipe joint in an embodiment of the present invention. Detailed implementation manners

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0071] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0072] It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further definition and explanation thereof is not required in subsequent figures.

[0073] As Figure 1 and Figure 2 shown, Figure 1 is a sectional view of the male connector along the axial direction, Figure 2 is a sectional view of the female connector along the axial direction. A torsional resistance drill pipe joint according to an embodiment of the present application includes a male connector and a female connector respectively disposed at two ends of the drill pipe. The male connector and the female connector are coaxially arranged. The outer surface of the male connector and the inner surface of the female connector are respectively a first tapered connection surface and a second tapered connection surface, and the slopes of the first tapered connection surface and the second tapered connection surface are the same; external threads and internal threads are respectively provided on the first tapered connection surface and the second tapered connection surface. The external threads are used for threaded connection with the second tapered connection surface of the female connector of the first drill pipe that matches it, and the internal threads are used for threaded connection with the first tapered connection surface of the male connector of the second drill pipe that matches it; the male connector and the female connector that match it, and the female connector and the male connector that match it correspond to a type of thread. Each type of thread has a set range of make-up turns and a set range of torsional resistance strength. The set range of make-up turns is 5 turns - 13 turns, and the set range of torsional resistance strength is not less than 10,000 ft-lbs.

[0074] The number of make-up turns determines the make-up speed of the mutually cooperating drill pipes. Generally speaking, the larger the number of make-up turns, the slower the make-up speed, and the smaller the number of make-up turns, the faster the make-up speed. The speed of the make-up process determines the proportion of non-working time during the tripping operation on the drilling platform. The faster the make-up speed, the smaller the non-working time (NTP, that is, the time occupied by the make-up process), which is equivalent to increasing the actual working time of the drill pipe and can improve work efficiency. And a faster make-up speed means a smaller number of make-up turns, and a smaller number of make-up turns may cause insufficient cooperation between the male and female connectors, affecting the connection stability of the male and female connectors.

[0075] In addition, the torsional strength of the drill pipe joint determines the maximum stress value that the male and female joints can resist when subjected to torque, directly reflecting the stability and durability of the male and female joints when subjected to torsional force. The higher the torsional strength, the stronger the anti-torsion performance of the material during the torsional deformation process, which also means that the connection and cooperation of the male and female joints are more firm and durable. At the same time, the higher the torsional strength, the faster the construction speed. Since the drill string can withstand a larger torque, it can penetrate the formation faster, improve the drilling speed and efficiency, and can also reduce the incidence of drill pipe sticking, thereby improving the construction efficiency. Through the coaxial conical connection surface design, combined with the accurately set number of make-up turns (5 - 13 turns) and the torsional strength range of not less than 10,000 ft-lbs, the joint structure and mechanical properties are optimized to ensure that the drill pipe joint can efficiently, stably and safely transmit torque under complex and harsh drilling conditions, reduce the failure rate, and enhance the overall drilling operation efficiency.

[0076] In some embodiments, each thread type is determined by the thread parameters of the male joint and the corresponding female joint. The thread parameters of the male joint and the female joint include the root radius of the thread. The range of the root radius of the thread of each male joint and female joint in any thread type is 0.038 in - 0.08 in. In this way, the contact stress distribution of the thread teeth in the axial and circumferential directions can be made more uniform. It can withstand the complex alternating loads generated during the ocean environment and drilling operations, effectively reduce the stress concentration at the thread root, reduce the generation and propagation of fatigue cracks, and ensure the long-term reliability of the drill pipe connection under harsh conditions.

[0077] In some embodiments, the thread parameters of the male joint and the female joint further include the half angle of the thread profile. The range of the half angle of the thread profile of each male joint and female joint in any thread type is 27.5° - 44.5°. The half angle of the thread profile within this range ensures that when the thread bears internal pressure, each thread tooth shares the load evenly, avoiding damage to individual thread teeth caused by local stress concentration, thereby significantly improving the overall reliability and sealing performance of the connection, effectively preventing medium leakage, and ensuring the safe and stable operation of the pipeline system.

[0078] In some embodiments, the thread parameters of the male joint and the female joint further include the taper. The range of the taper of each male joint and female joint in any thread type is 1 / 16 - 1 / 6. In this way, the male and female joints can gradually achieve close fit during the tightening process, especially forming a reliable sealing contact at the sealing surface. As the make-up progresses, the contact pressure between the threads and the sealing surface increases evenly, maximizing the make-up speed and efficiency between the male and female joints.

[0079] In some embodiments, when the buckle type is the designed buckle type, the taper and the root arc radius also satisfy the following corresponding relationships. When the taper is 1 / 16, the corresponding root arc radius ranges from 0.05 in to 0.065 in; when the taper is 1 / 12, the corresponding root arc radius ranges from 0.04 in to 0.060 in; when the taper is 1 / 10, the corresponding root arc radius ranges from 0.045 in to 0.055 in. This makes the stress distribution at the threaded connection part more uniform and reasonable, effectively reducing stress concentration, enhancing the load-bearing capacity and anti-fatigue performance of the connection, so as to be able to cope with various complex loads.

[0080] In some embodiments, the thread parameters of the male connector and the female connector also include the pitch. The pitch range of each male connector and female connector in any buckle type is 0.250 in - 0.364 in. Furthermore, when the male and female connectors bear huge tensile forces, the force distribution can be made more uniform. Compared with too dense or too sparse pitches, within this range, each thread can effectively share the load, reduce the stress concentration phenomenon, and prevent the threads from deforming or being damaged due to excessive local stress.

[0081] In some embodiments, the number of make-up turns and the thread parameters satisfy the following relational formula:

[0082] ;

[0083] In the formula, N is the number of make-up turns, θ is the half thread angle, tpr is the taper, P is the pitch, and R is the root arc radius. Through the selected thread parameters, the number of make-up turns can be accurately calculated, optimizing the mechanical properties of the threaded connection. For example, when the half thread angle, taper, pitch, and root arc radius are determined according to the design, the number of make-up turns obtained using this relational formula can ensure that when the thread transmits huge torque and axial force, the stress distribution is uniform, avoiding the generation of fatigue cracks caused by local stress concentration, thus significantly improving the fatigue life and reliability of the connection.

[0084] In some embodiments, the partial derivative of the number of make-up turns with respect to the taper satisfies the following relational formula:

[0085] ;

[0086] In the formula, N is the number of make-up turns, θ is the half thread angle, tpr is the taper, P is the pitch, and R is the root arc radius. Refer to Figure 4 , Figure 4This is a graph showing the relationship between the number of turns during make-up and the taper of a torsional drill pipe joint in an embodiment of the present invention. In this graph, the abscissa represents the taper, and the ordinate represents the number of turns during make-up (unit: turn). It can be seen from the graph that when the other thread parameters are fixed, the number of turns during make-up is negatively correlated with the taper. Therefore, by making fine adjustments to the taper, the change in the number of turns during make-up can be precisely controlled, thereby obtaining the trend of the relationship change between the number of turns during make-up and the taper, and providing a theoretical reference for the thread design of male and female joints.

[0087] In some embodiments, referring to Figure 4 , when the taper is 1 / 10, the corresponding number of turns during make-up is 7.01 turns. Compared with a taper of 1 / 16, the corresponding number of turns during make-up is 11.8 turns, which can significantly reduce the number of turns during make-up and reduce the non-productive time (NPT), thereby improving work efficiency. Compared with a taper of 1 / 6, the corresponding number of turns during make-up is 4.2 turns, and the male and female joints can be fully connected, thereby improving the connection sealing performance between the male and female joints.

[0088] In some embodiments, the partial derivative of the number of turns during make-up with respect to the root radius of the thread satisfies the following relational expression:

[0089] ;

[0090] In the formula, N is the number of turns during make-up, θ is the half thread angle, tpr is the taper, P is the pitch, and R is the root radius of the thread. Referring to Figure 5 , Figure 5 This is a graph showing the relationship between the number of turns during make-up and the root radius of the thread of a torsional drill pipe joint in an embodiment of the present invention. In this graph, the abscissa represents the root radius of the thread (unit: ), and the ordinate represents the number of turns during make-up (unit: turn). It can be seen from the graph that when the other thread parameters are fixed, the number of turns during make-up is negatively correlated with the root radius of the thread. Therefore, by making fine adjustments to the root radius of the thread, the change in the number of turns during make-up can be precisely controlled, thereby obtaining the trend of the relationship change between the number of turns during make-up and the root radius of the thread, and providing a theoretical reference for the thread design of male and female joints.

[0091] In some embodiments, referring to Figure 5 , when the root radius of the thread is 1.27 , the corresponding number of turns during make-up is 7.01 turns, or when the taper is 0.10, the corresponding number of turns during make-up is 8.9 turns. Compared with a root radius of the thread of 2.1 , the corresponding number of turns during make-up is 1.6 turns, and the male and female joints can be fully connected, thereby improving the connection sealing performance between the male and female joints.

[0092] In some embodiments, the partial derivative of the number of turns during make-up with respect to the pitch satisfies the following relational expression:

[0093] ;

[0094] Wherein, N is the number of threading turns, θ is the half thread angle, tpr is the taper, P is the pitch, and R is the root radius of the thread. Refer to Figure 6 , Figure 6 Fig. is the relationship diagram between the number of threading turns and the pitch of a torsional drill pipe joint in an embodiment of the present invention. In this figure, the abscissa represents the pitch (unit:

[0095] In some embodiments, refer to Figure 6 , when the pitch is 7.257 , the corresponding number of threading turns is 7.01 turns, or when the pitch is 6.35 , the corresponding number of threading turns is 6.06 turns, or when the pitch is 10.16 , the corresponding number of threading turns is 8.92 turns, which can significantly reduce the number of threading turns, reduce the non-productive time (NPT), and thus improve the work efficiency.

[0096] In some embodiments, refer to Figure 3 , Figure 3 Fig. Figure 3 is the relationship diagram between the number of threading turns and the half thread angle of a torsional drill pipe joint in an embodiment of the present invention. In this figure, the abscissa represents the half thread angle (unit: °), and the ordinate represents the number of threading turns (unit: turns). According to

[0097] In some embodiments, when the half thread angle is 30°, the corresponding number of threading turns is 8.0 turns; when the half thread angle is 35°, the corresponding number of threading turns is 7.0 turns; when the half thread angle is 45°, the corresponding number of threading turns is 5.6 turns. This can significantly reduce the number of threading turns, reduce the non-productive time (NPT), and thus improve the work efficiency.

[0098] In some embodiments, refer to Figure 7 , Figure 7 Fig. is the relationship diagram between the number of threading turns and the taper and the root radius of the thread of a torsional drill pipe joint in an embodiment of the present invention. In the figure, the coordinate in the X direction represents the root radius R of the thread (unit: Figure 7It can be seen that the influence trends of the two parameter variables of taper and root arc radius on the number of turns to make up the thread indicate that, compared with the taper, the root arc radius has a greater influence on the number of turns to make up the thread. When obtaining the corresponding number of turns to make up the thread by adjusting the thread parameters, according to the design requirements, the degrees of adjusting the root arc and taper (with other parameters unchanged) can be controlled to obtain different numbers of turns to make up the thread. For example, when it is necessary to quickly lower the number of turns to make up the thread, the degree of adjusting the root arc radius can be considered to be increased within a reasonable range, so as to achieve a quick adjustment of the number of turns to make up the thread.

[0099] In some embodiments, the root arc radius, pitch, thread angle half angle and taper satisfy the following relational expression:

[0100] ;

[0101] In the formula, θ is the thread angle half angle, tpr is the taper, P is the pitch, R is the root arc radius, and Rmax is the maximum value of the root arc radius. After determining the pitch, thread angle half angle and taper according to the design requirements, the root arc radius is calculated through this relational expression, and based on this, the stress distribution and deformation conditions when the connection bears complex loads are predicted, improving the stability performance of the male and female joint connection.

[0102] In some embodiments, both ends of the drill pipe are respectively connected to the other two drill pipes (the first drill pipe and the second drill pipe) that cooperate with it. For example, after the male joint of this drill pipe is cooperatively connected with the female joint of the first drill pipe, it is the first thread type, and after the female joint of this drill pipe is cooperatively connected with the male joint of the second drill pipe, it is the second thread type. The first thread type and the second thread type can be the same or different, and can be selected according to the specific working environment. For example, for offshore deep water and ultra-deep water oil and gas development in the Gulf of Mexico, and for deep wells, ultra-deep wells (6000 meters in depth) and extended reach drilling in the North American onshore market, the main requirements of the well conditions for the performance of drill pipe joints are better fatigue performance, operation efficiency and lower repair rate, etc., then a thread type with a relatively small number of turns to make up the thread and an appropriate torsional strength needs to be selected. For example, the number of turns to make up the thread can be selected to be about 9 turns, and the corresponding torsional strength is selected to be about 35000 ft-lbs. Such a thread type has a faster make-up speed (smaller NTP) and also has good torsional strength, which can meet the use requirements of ultra-deep wells.

[0103] In some embodiments, the drill pipe in this embodiment includes multiple designed thread types (thread type 01, thread type 02, thread type 03, thread type 04, thread type 05, thread type 06, thread type 07, thread type 08, thread type 09, thread type 10, thread type 11, thread type 12, thread type 13, etc.). The range of the common make-up turns for the multiple designed thread types, that is, the make-up turn range for each thread type is 5 turns - 13 turns. For each of the above-mentioned multiple thread types, there is a minimum torsional strength corresponding to it, and at the same time, the minimum torsional strength of each thread type is less than the set range of torsional strength (10000 ft-lbs).

[0104] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), make-up turns (turns), and torsional strength (ft-lbs) of thread type 01 are respectively: 3 1 / 9 - 3 1 / 7, 1 1 / 3 - 1 2 / 3, 1:9 - 1:7, 0.04 - 0.06, 5 - 6, 11000 - 13000.

[0105] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), make-up turns (turns), and torsional strength (ft-lbs) of thread type 01 are respectively: 3 1 / 8, 1 1 / 2, 1:8, 0.05, 5, 12000.

[0106] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), make-up turns (turns), and torsional strength (ft-lbs) of thread type 02 are respectively: 3 1 / 3 - 3 3 / 7, 1 3 / 8 - 1 7 / 8, 1:9 - 1:7, 0.04 - 0.06, 5 - 6, 14000 - 16000.

[0107] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), make-up turns (turns), and torsional strength (ft-lbs) of thread type 02 are respectively: 3 3 / 8, 1 5 / 8, 1:8, 0.05, 5, 15000.

[0108] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), make-up turns (turns), and torsional strength (ft-lbs) of thread type 03 are respectively: 3 2 / 3 - 4 1 / 4, 1 2 / 3 - 2 1 / 3, 1:11 - 1:9, 0.04 - 0.06, 7 - 9, 20000 - 24000.

[0109] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of the button type 03 are respectively: 4, 2, 1:10, 0.05, 8, 23000.

[0110] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of the button type 04 are respectively: 4 1 / 9 - 4 3 / 8, 2 1 / 7 - 2 3 / 8, 1:11 - 1:9, 0.04 - 0.06, 7 - 9, 23000 - 27000.

[0111] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of the button type 04 are respectively: 4 1 / 8, 2 1 / 8, 1:10, 0.05, 8, 25000.

[0112] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of the button type 05 are respectively: 4 5 / 8 - 5, 2 9 / 16 - 2 15 / 16, 1:14 - 1:11, 0.05 - 0.07, 6 - 8, 34000 - 36000.

[0113] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of the button type 05 are respectively: 4 7 / 8, 2 11 / 16, 1:12, 0.06, 7, 35000.

[0114] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of the button type 06 are respectively: 5 1 / 5 - 5 3 / 4, 2 3 / 4 - 3 1 / 3, 1:13 - 1:10, 0.05 - 0.07, 6 - 8, 49000 - 61000.

[0115] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of the button type 06 are respectively: 5 1 / 4, 3, 1:12, 0.06, 7, 50000.

[0116] The drill pipes with coupling type 01, coupling type 02, coupling type 03, coupling type 04, coupling type 05 or coupling type 06 have moderate torsional strength and are suitable for occasions where general torque needs to be transmitted. For example, in the connection of drill pipes in some small oil drilling equipment, when the drill pipe rotates and drills, it can effectively transmit torque to ensure the normal operation of the drill bit. At the same time, the tensile strength of this type is also considerable. During the drilling process, the drill pipe needs to bear its own gravity and the axial tension generated by lifting the drill bit, etc. The relatively high tensile strength can prevent the drill pipe from breaking during the lifting process, ensuring the safety and reliability of the equipment. Moreover, the inner and outer diameter dimensions of this type are relatively moderate and will not occupy too much space in the internal structure of small drilling equipment with limited space.

[0117] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns) and torsional strength (ft-lbs) of coupling type 07 are respectively: 6 1 / 2 - 6 7 / 8, 3 3 / 4 - 4 1 / 3, 1:13 - 1:10, 0.05 - 0.07, 6 - 8, 89000 - 91000.

[0118] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns) and torsional strength (ft-lbs) of coupling type 07 are respectively: 6 5 / 8, 4, 1:12, 0.06, 7, 90000.

[0119] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns) and torsional strength (ft-lbs) of coupling type 08 are respectively: 6 4 / 5 - 7 2 / 7, 3 3 / 4 - 4 1 / 2, 1:15 - 1:12, 0.06 - 0.08, 5 - 8, 100000 - 120000.

[0120] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns) and torsional strength (ft-lbs) of coupling type 08 are respectively: 7, 4 1 / 4, 1:14, 0.07, 6, 110000.

[0121] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns) and torsional strength (ft-lbs) of coupling type 09 are respectively: 7 7 / 8 - 8 1 / 8, 4 3 / 4 - 5 1 / 5, 1:15 - 1:13, 0.06 - 0.08, 5 - 8, 130000 - 170000.

[0122] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of buckle type 09 are respectively: 8, 5, 1:14, 0.07, 6, 150000.

[0123] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of buckle type 10 are respectively: 8 1 / 3 - 8 3 / 4, 4 3 / 4 - 5 3 / 4, 1:18 - 1:15, 0.06 - 0.08, 5 - 8, 180000 - 200000.

[0124] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of buckle type 10 are respectively: 8 1 / 2, 5 1 / 4, 1:16, 0.07, 6, 190000.

[0125] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of buckle type 11 are respectively: 8 3 / 8 - 8 7 / 8, 5 1 / 4 - 5 3 / 4, 1:18 - 1:15, 0.06 - 0.08, 5 - 8, 180000 - 190000.

[0126] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of buckle type 11 are respectively: 8 5 / 8, 5 1 / 2, 1:16, 0.07, 6, 185000.

[0127] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of buckle type 12 are respectively: 9 1 / 2 - 10, 5 7 / 8 - 6 1 / 4, 1:18 - 1:15, 0.06 - 0.08, 5 - 8, 300000 - 330000.

[0128] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius (in), number of turns for make-up (turns), and torsional strength (ft-lbs) of buckle type 12 are respectively: 9 7 / 8, 6, 1:16, 0.07, 6, 310000.

[0129] In some embodiments, the ranges of the outer diameter (in), inner diameter (in), taper, root radius of the thread (in), number of turns for making up the connection (turns), and torsional strength (ft-lbs) of the coupling type 13 are respectively: 10 1 / 2 - 11, 6 1 / 8 - 7, 1:18 - 1:15, 0.06 - 0.08, 5 - 8, 340000 - 370000.

[0130] As a preferred embodiment, referring to Table 1, the values of the outer diameter (in), inner diameter (in), taper, root radius of the thread (in), number of turns for making up the connection (turns), and torsional strength (ft-lbs) of the coupling type 13 are respectively: 10 5 / 8, 6 5 / 8, 1:16, 0.07, 6, 350000.

[0131] The drill pipes with coupling type 08, coupling type 09, coupling type 10, coupling type 11, coupling type 12 or coupling type 13 have high torsional strength, can meet the connection requirements of large torques, can effectively transmit the required torque, and at the same time resist the torque fluctuations during drilling, preventing the joints from being damaged due to torque overload. At the same time, this type has high tensile properties and has good performance in bearing axial tension. At the same time, the outer diameter of this type is relatively large, reducing the fluid resistance and facilitating the transportation of the fluid.

[0132]

[0133] Table 1

[0134] The embodiment of the present application also provides a drill pipe joint with torsional resistance, which includes a male joint and a female joint respectively arranged at both ends of the drill pipe. The male joint and the female joint are coaxially arranged. The outer surface of the male joint and the inner surface of the female joint are respectively a first tapered connection surface and a second tapered connection surface, and the slopes of the first tapered connection surface and the second tapered connection surface are the same; an external thread and an internal thread are respectively arranged on the first tapered connection surface and the second tapered connection surface. The external thread is used for threaded connection with the second tapered connection surface of the female joint of the first drill pipe that matches it, and the internal thread is used for threaded connection with the first tapered connection surface of the male joint of the second drill pipe that matches it; the male joint and the female joint that match it, and the female joint and the male joint that match it respectively correspond to a coupling type, and each coupling type has a set range of number of turns for making up the connection. Each coupling type is determined by the thread parameters of the male joint and the female joint. The thread parameters of the male joint and the female joint include the root radius of the thread, the half angle of the thread profile, the taper, and the pitch; the number of turns for making up the connection satisfies the following relationship with the root radius of the thread, the half angle of the thread profile, the taper, and the pitch:

[0135] ;

[0136] Wherein, N is the number of fastening turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc of the thread. The number of fastening turns can be accurately calculated through the selected thread parameters, optimizing the mechanical properties of the thread connection. For example, when the half angle of the thread profile, taper, pitch, and radius of the root arc of the thread are determined according to the design, the number of fastening turns obtained using this relationship can ensure that when the thread transmits a large torque and axial force, the stress distribution is uniform, avoiding the generation of fatigue cracks caused by local stress concentration, thereby significantly improving the fatigue life and reliability of the connection.

[0137] In some embodiments, the partial derivative of the number of fastening turns with respect to the taper satisfies the following relationship:

[0138] ;

[0139] Wherein, N is the number of fastening turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc of the thread. Refer to Figure 4 , in this figure, the abscissa represents the taper and the ordinate represents the number of fastening turns. It can be seen from the figure that when the other thread parameters are fixed, the number of fastening turns and the taper are negatively correlated. Therefore, by making a fine adjustment to the taper, the change in the number of fastening turns can be precisely controlled, thereby obtaining the changing trend of the relationship between the number of fastening turns and the taper, and providing a theoretical reference for the thread design of the male and female joints.

[0140] In some embodiments, refer to Figure 4 , when the taper is 1 / 10, the corresponding number of fastening turns is 7.01 turns. Compared with a taper of 1 / 16, the corresponding number of fastening turns is 11.8 turns, which can significantly reduce the number of fastening turns and shorten the non - working time (NPT), thereby improving work efficiency. Compared with a taper of 1 / 6, the corresponding number of fastening turns is 4.2 turns, and the male and female joints can be fully connected, thereby improving the fastening speed and efficiency between the male and female joints.

[0141] In some embodiments, the partial derivative of the number of fastening turns with respect to the radius of the root arc of the thread satisfies the following relationship:

[0142] ;

[0143] Wherein, N is the number of fastening turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc of the thread.

[0144] Refer to Figure 5, in this figure, the abscissa represents the root arc radius, and the ordinate represents the number of turns during screwing. It can be seen from the figure that when the other thread parameters are fixed, the number of turns during screwing is negatively correlated with the root arc radius. Therefore, by making fine adjustments to the root arc radius, the change in the number of turns during screwing can be precisely controlled, thereby obtaining the changing trend of the relationship between the number of turns during screwing and the root arc radius, and providing a theoretical reference for the thread design of male and female joints.

[0145] In some embodiments, referring to Figure 5 , when the root arc radius is 1.27 , the corresponding number of turns during screwing is 7.01 turns, or when the root arc radius is 0.97 , the corresponding number of turns during screwing is 8.9 turns. Compared with when the root arc radius is 2.1 , the corresponding number of turns during screwing is 1.6 turns, the male and female joints can be fully connected, thereby improving the fatigue performance between the male and female joints.

[0146] In some embodiments, the partial derivative of the number of turns during screwing with respect to the pitch satisfies the following relational expression:

[0147] ;

[0148] In the formula, N is the number of turns during screwing, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the root arc radius.

[0149] Referring to Figure 6 , in this figure, the abscissa represents the pitch, and the ordinate represents the number of turns during screwing. It can be seen from the figure that when the other thread parameters are fixed, the number of turns during screwing is positively correlated with the pitch. Therefore, by making fine adjustments to the pitch, the change in the number of turns during screwing can be precisely controlled, thereby obtaining the changing trend of the relationship between the number of turns during screwing and the pitch, and providing a theoretical reference for the thread design of male and female joints.

[0150] In some embodiments, referring to Figure 6 , when the pitch is 7.257 , the corresponding number of turns during screwing is 7.01 turns, or when the pitch is 6.35 , the corresponding number of turns during screwing is 6.06 turns, or when the pitch is 10.16 , the corresponding number of turns during screwing is 8.92 turns, which can significantly reduce the number of turns during screwing, reduce the non - working time (NPT), and thus improve the working efficiency.

[0151] In some embodiments, referring to Figure 3 , in this figure, the abscissa represents the half angle of the thread profile, and the ordinate represents the number of turns during screwing. According to Figure 3 , it can be known that there is a negative correlation between the number of turns during screwing and the half angle of the thread profile, that is, as the half angle of the thread profile increases, the number of turns during screwing decreases.

[0152] In some embodiments, when the thread profile half angle is 30°, the corresponding number of make-up turns is 8.0 turns; when the thread profile half angle is 35°, the corresponding number of make-up turns is 7.0 turns; when the thread profile half angle is 45°, the corresponding number of make-up turns is 5.6 turns. This can significantly reduce the number of make-up turns, decrease the non-operating time (NPT), and thus improve work efficiency.

[0153] In some embodiments, referring to Figure 7 , the coordinate in the X direction in the figure represents the root arc radius R, the coordinate in the Y direction represents the taper tpr, and the vertical coordinate represents the number of make-up turns. According to Figure 7 , it can be seen that the influence trend of the two parameter variables of taper and root arc radius on the number of make-up turns indicates that, compared with the taper, the root arc radius has a greater influence on the number of make-up turns. When obtaining the corresponding number of make-up turns by adjusting the thread parameters, the degree of adjustment of the root arc and taper (with other parameters unchanged) can be controlled according to the design requirements to obtain different numbers of make-up turns. For example, when it is necessary to quickly reduce the number of make-up turns, the degree of adjustment of the root arc radius can be considered to be increased within a reasonable range, so as to achieve a quick adjustment of the number of make-up turns.

[0154] In some embodiments, the root arc radius, pitch, thread profile half angle, and taper satisfy the following relationship:

[0155] ;

[0156] In the formula, θ is the thread profile half angle, tpr is the taper, P is the pitch, R is the root arc radius, and Rmax is the maximum value of the root arc radius. After determining the pitch, thread profile half angle, and taper according to the design requirements, the root arc radius is calculated through this relationship, and based on this, the stress distribution and deformation conditions when the connection bears complex loads are predicted, improving the stability of the male-female joint connection.

[0157] In some embodiments, each thread type has a set range of the number of make-up turns and a set range of torsional strength. The set range of the number of make-up turns is 5 turns - 13 turns, and the set range of torsional strength is not less than 10000 ft-lbs. The number of make-up turns determines the make-up speed of the mating drill pipes. Generally speaking, the larger the number of make-up turns, the slower the make-up speed; the smaller the number of make-up turns, the faster the make-up speed. The speed of the make-up process determines the proportion of non-operating time during the tripping operation on the drilling platform. The faster the make-up speed, the smaller the non-operating time (NTP, that is, the time occupied by the make-up process), which is equivalent to increasing the actual working time of the drill pipe and can improve work efficiency. And a faster make-up speed means a smaller number of make-up turns, and a smaller number of make-up turns may cause insufficient mating between the male and female joints, affecting the connection stability of the male and female joints.

[0158] In addition, the torsional strength of the drill pipe joint determines the maximum stress value that the male and female joints can resist when subjected to torque, directly reflecting the stability and durability of the male and female joints when subjected to torsional force. The higher the torsional strength, the stronger the anti-torsion performance of the material during the torsional deformation process, which also means that the connection and cooperation of the male and female joints are more firm and durable. At the same time, the higher the torsional strength, the faster the construction speed. Since the drill string can withstand a larger torque, it can penetrate the formation faster, improve the drilling speed and efficiency, and also reduce the incidence of drill pipe sticking, thereby improving the construction efficiency. Through the coaxial conical connection surface design, combined with the accurately set number of make-up turns (5 - 13 turns) and the torsional strength range not less than 10,000 ft-lbs, the joint structure and mechanical properties are optimized to ensure that under complex and harsh drilling conditions, the drill pipe joint can efficiently, stably and safely transmit torque, reduce the failure rate, and enhance the overall drilling operation efficiency.

[0159] In some embodiments, the range of the root radius of the thread of each male joint and female joint in any thread type is 0.038 in - 0.08 in. In this way, the contact stress distribution of the thread teeth in the axial and circumferential directions can be made more uniform. It can withstand the complex alternating loads generated during the ocean environment and the drilling operation, effectively reduce the stress concentration at the thread root, reduce the generation and propagation of fatigue cracks, and ensure the long-term reliability of the pipe string connection under harsh conditions.

[0160] In some embodiments, the range of the thread half angle of each male joint and female joint in any thread type is 27.5° - 44.5°. This range of thread half angles ensures that during the drill pipe thread connection process, when the thread bears the internal pressure, each thread tooth evenly shares the load together, avoiding damage to individual thread teeth caused by local stress concentration, thereby significantly improving the overall reliability and sealing performance of the connection, effectively preventing medium leakage, and ensuring the safe and stable operation of the pipeline system.

[0161] In some embodiments, the range of the taper of each male joint and female joint in any thread type is 1 / 16 - 1 / 6. In this way, the male and female joints can gradually achieve a tight fit during the tightening process, especially forming a reliable sealing contact at the sealing surface. As the make-up progresses, the contact pressure between the threads and the sealing surface increases evenly, maximizing the make-up speed and efficiency between the male and female joints.

[0162] In some embodiments, when the buckle type is the designed buckle type, the taper and the root radius of the thread also satisfy the following corresponding relationships. When the taper is 1 / 16, the corresponding root radius of the thread ranges from 0.05 in to 0.065 in; when the taper is 1 / 12, the corresponding root radius of the thread ranges from 0.04 in to 0.060 in; when the taper is 1 / 10, the corresponding root radius of the thread ranges from 0.045 in to 0.055 in. This makes the stress distribution at the threaded connection part more uniform and reasonable, effectively reducing stress concentration, enhancing the load-bearing capacity and anti-fatigue performance of the connection, and thus being able to handle various complex loads.

[0163] In some embodiments, the pitch range of each male joint and female joint in any buckle type is 0.250 in - 0.364 in. Furthermore, when the male and female joints bear a huge tensile force, the force distribution can be made more uniform. Compared with too dense or too sparse pitches, within this range, each thread can effectively share the load, reducing the stress concentration phenomenon and preventing the threads from deforming or being damaged due to excessive local stress.

[0164] The embodiment of the present application also provides a method for designing a drill pipe joint, including: First step, respectively determine the range of the number of make-up turns and the torsional strength of the designed buckle type according to the number of make-up turns and the torsional strength of the standard buckle type and the special buckle type. Among them, the number of make-up turns of the designed buckle type is 5 - 13 turns, and the set range of the torsional strength is not less than 10000 ft-lbs; Second step, set the thread parameters in the designed buckle type. The thread parameters include the root radius of the thread, the taper, the thread profile half angle, and the pitch, and select the root radius of the thread and the pitch according to the range of the number of make-up turns and the torsional strength; Third step, select a series of taper ranges according to the range of the number of make-up turns and the torsional strength; Fourth step, according to the relationship formula between the thread parameters and the number of make-up turns, obtain a series of ranges of the root radius of the thread corresponding to the taper range. It can determine the range of key parameters of the designed buckle type based on the empirical data of the standard buckle type and the special buckle type, and has good flexibility. For example, in the field of oil exploitation, the requirements for drill pipe joints vary greatly for different well depths, geological conditions, and exploitation processes. Through this design method, suitable drill pipe joints can be designed for specific situations such as shallow wells, deep wells, ultra-deep wells, or different rock formations. For shallow wells with relatively simple geological conditions, a lower torsional strength can be selected without considering the influence of the number of make-up turns, such as 10 make-up turns and a lower torsional strength (such as 20000 ft-lbs) in the corresponding specification; while for the exploitation of deep wells, ultra-deep wells, or horizontal wells and other formations, a higher torsional strength (110000 ft-lbs) and a smaller number of make-up turns (such as 6 turns) in the corresponding specification are selected to meet the usage requirements under complex working conditions.

[0165] In some embodiments, the number of make-up turns satisfies the following relationship formula with the root radius of the thread, the thread profile half angle, the taper, and the pitch:

[0166] ;

[0167] In the formula, N is the number of make-up turns, θ is the half angle of the thread profile, tpr is the taper, P is the pitch, and R is the radius of the root arc. The number of make-up turns can be accurately calculated through the selected thread parameters, optimizing the mechanical properties of the threaded connection. For example, when the half angle of the thread profile, taper, pitch, and radius of the root arc are determined according to the design, the number of make-up turns obtained using this relationship can ensure that when the thread transmits a large torque and axial force, the stress distribution is uniform, avoiding the generation of fatigue cracks caused by local stress concentration, thereby significantly improving the fatigue life and reliability of the connection.

[0168] In some embodiments, it is necessary to select appropriate number of make-up turns and torsional strength. Within the reasonable range of the number of make-up turns (between the theoretically minimum and maximum number of make-up turns) and within the reasonable range of torsional strength (theoretically minimum torsional strength), a better number of make-up turns and torsional strength are selected to better meet the requirements for make-up speed and torsional performance. Referring to Table 2, taking the NC38 thread type (standard thread type) and the special thread type HLIST39 in the API standard as examples for various thread types on the market, NC38 in the API standard is the most basic thread type for torsional performance in the current market, and HLIST39 is a special thread type with better torsional performance. The range of the number of make-up turns is selected as 5 - 13 turns, and the range of torsional strength is selected as not less than 32300 ft-lbs, ensuring that the male and female joints have a suitable number of make-up turns, reducing the non-productive time (NPT), and at the same time, the torsional strength of the male and female joints is also appropriate, capable of meeting the usage requirements of the drill pipe.

[0169]

[0170] Table 2

[0171] Moreover, although the number of make-up turns of 5 - 13 turns already meets the requirements for make-up speed, the number of make-up turns can still be further divided into three ranges according to the requirements for the make-up speed of the drill pipe at the drilling site: high-efficiency range (5.0 - 7.3), medium range (7.4 - 10.5), and general range (10.6 - 13.0). The high-efficiency range (5.0 - 7.3) is applicable to cases where the construction period is short and it is necessary to significantly reduce the non-productive time, and the medium range (7.4 - 10.5) and general range (10.6 - 13.0) are applicable to cases where better connection cooperation between the male and female joints is required.

[0172] In some embodiments, referring to Table 3, the taper and the root arc radius also satisfy the following corresponding relationships. When the taper is 1 / 16, the corresponding root arc radius ranges from 0.05 in to 0.065 in; when the taper is 1 / 12, the corresponding root arc radius ranges from 0.04 in to 0.060 in; when the taper is 1 / 10, the corresponding root arc radius ranges from 0.045 in to 0.055 in. This makes the stress distribution at the threaded connection part more uniform and reasonable, effectively reducing stress concentration, enhancing the load-bearing capacity and anti-fatigue performance of the connection, and thus enabling it to handle various complex loads.

[0173]

[0174] Table 3

[0175] In some embodiments, the torsional strength of the male and female joints is calculated by the following formula:

[0176]

[0177] where, is the cross-sectional area of the dangerous section at the column shoulder position, with the unit of ;

[0178] is the cross-sectional area of the dangerous section at the sub-shoulder position, with the unit of ;

[0179] is the average radius of the contact ring of the main shoulder surface, with the unit of ;

[0180] is the average radius of the contact ring of the sub-shoulder surface, with the unit of ;

[0181] is the yield torque, with the unit of ;

[0182] is the minimum yield strength of the material, with the unit of ;

[0183] is the pitch of the thread, with the unit of ;

[0184] is the actual friction coefficient of the contact surface between the shoulder and the thread, which is generally 0.08 for drill pipe design;

[0185] is the half angle of the thread profile;

[0186] , is the average radius of the connection thread portion, in units of ;

[0187] is the length of the male connector;

[0188] , where the maximum value of = is limited by calculated when ;

[0189] is the main shoulder critical section, which is , the smaller value of the two;

[0190] , when there is no stress relief groove;

[0191] , when there is a stress relief groove;

[0192] is the diameter of the stress relief groove;

[0193] is the pitch diameter of the thread reference at the gauge specified point;

[0194] Inner diameter;

[0195] Outer diameter;

[0196] ;

[0197] Height of the original thread triangle;

[0198] Height of the bottom of the thread tooth;

[0199] Taper;

[0200] ;

[0201] Boring diameter of the female connector;

[0202] ;

[0203] Nose end diameter of the male connector;

[0204] .

[0205] Combined with Table 1, it can be seen from the above formula that the torsional strength of each type of connection is also related to parameters such as the inner diameter, outer diameter, taper, pitch, and half angle of the thread profile corresponding to the male and female joints. When the other parameters in the torsional formula remain unchanged, according to the requirements for the torsional strength of the drill pipe joint in the actual working conditions, the torsional strength suitable for the design requirements can be obtained by adjusting various geometric parameters (inner diameter, outer diameter, taper, pitch, half angle of the thread profile) of the joint. For example, when designing a drill pipe joint for deep well drilling, since it needs to withstand higher torque, the torsional strength of the joint can be calculated and optimized according to the formula by increasing the outer diameter, inner diameter or adjusting the pitch diameter of the thread, etc., to ensure that it can meet the drilling requirements under the complex geological conditions of deep wells. In addition, this formula helps to accurately predict the torsional performance of the drill pipe joint. By inputting different combinations of geometric parameters, a relatively accurate prediction of the torsional strength of the drill pipe joint can be obtained in advance. For example, when developing a high-strength drill pipe joint, the torsional strength is calculated using the formula and compared with the torque output capacity of the existing drilling equipment to determine whether the new joint can be adapted, avoiding problems such as connection failure or equipment damage caused by insufficient or excessive torsional strength.

[0206] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0207] In addition, the terms "horizontal", "vertical", etc. do not mean that the components are required to be absolutely horizontal or hanging vertically, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0208] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0209] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A torsion-resistant drill pipe joint, characterized in that: The drill pipe comprises a male joint and a female joint respectively arranged at both ends of the drill pipe, the male joint and the female joint are coaxially arranged, the outer surface of the male joint and the inner surface of the female joint are respectively a first tapered connection surface and a second tapered connection surface, and the first tapered connection surface and the second tapered connection surface have the same inclination; the first tapered connection surface and the second tapered connection surface are respectively provided with an external thread and an internal thread, the external thread is used for threaded connection with the second tapered connection surface of the female joint of the first drill pipe matched therewith, and the internal thread is used for threaded connection with the first tapered connection surface of the male joint of the second drill pipe matched therewith; The male connector and the female connector that match it, and the female connector and the male connector that match it correspond to a buckle type, each of the buckle types is determined by the thread parameters of the male connector and the corresponding female connector, each of the buckle types has a set range of buckle turns and torsional strength, the setting range corresponding to the buckle turns is 5 turns to 13 turns, and the setting range corresponding to the torsional strength is not less than 10000 ft-lbs; the buckle turns and the thread parameters also satisfy the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

2. The torsion-resistant drill pipe joint according to claim 1, characterized in that: The thread parameters of the male connector and the female connector include a tooth bottom arc radius, and the tooth bottom arc radius of each of the male connector and the female connector in any thread type ranges from 0.038in to 0.08in.

3. The torsion-resistant drill pipe joint according to claim 2, characterized in that: The thread parameters of the male connector and the female connector also include a thread profile half angle, and the thread profile half angle of each of the male connector and the female connector in any thread type ranges from 27.5° to 44.5°.

4. The torsion-resistant drill pipe joint according to claim 3, characterized in that: The thread parameters of the male connector and the female connector also include taper, and the taper range of each of the male connector and the female connector in any thread type is 1 / 16 - 1 / 6.

5. The torsion-resistant drill pipe joint according to claim 4, characterized in that: When the buckle type is a designed buckle type, the taper and the tooth bottom arc radius also satisfy the following corresponding relationship: when the taper is 1 / 16, the corresponding tooth bottom arc radius range is 0.05in~0.065in; when the taper is 1 / 12, the corresponding tooth bottom arc radius range is 0.04in~0.060in; when the taper is 1 / 10, the corresponding tooth bottom arc radius range is 0.045in~0.055in.

6. The torsion-resistant drill pipe joint according to claim 5, characterized in that: The thread parameters of the male connector and the female connector also include a pitch, and the pitch range of each of the male connector and the female connector in any thread type is 0.250in-0.364in.

7. The torsion-resistant drill pipe joint according to claim 6, characterized in that: The partial derivative of the number of make-up turns and the taper satisfies the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

8. The torsion-resistant drill pipe joint according to claim 7, characterized in that: The partial derivative of the number of thread turns and the radius of the tooth bottom arc satisfies the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

9. The torsionally resistant drill pipe joint according to claim 8, characterized in that: The partial derivative of the number of make-up turns and the pitch satisfies the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

10. The torsionally resistant drill pipe joint according to claim 9, characterized in that: The tooth bottom arc radius, the thread pitch, the tooth profile half angle and the taper satisfy the following relationship: ； Where θ is the tooth profile half angle, tpr is the taper, P is the pitch, R is the tooth bottom arc radius, and Rmax is the maximum value of the tooth bottom arc radius.

11. A torsion-resistant drill pipe joint, characterized in that: The drill pipe comprises a male joint and a female joint respectively arranged at both ends of the drill pipe, the male joint and the female joint are coaxially arranged, the outer surface of the male joint and the inner surface of the female joint are respectively a first tapered connection surface and a second tapered connection surface, and the first tapered connection surface and the second tapered connection surface have the same inclination; the first tapered connection surface and the second tapered connection surface are respectively provided with an external thread and an internal thread, the external thread is used for threaded connection with the second tapered connection surface of the female joint of the first drill pipe matched therewith, and the internal thread is used for threaded connection with the first tapered connection surface of the male joint of the second drill pipe matched therewith; The male connector and the female connector matched therewith and the female connector and the male connector matched therewith respectively correspond to a buckle type, each buckle type has a set range of buckle turns, each buckle type is determined by the thread parameters of the male connector and the female connector, and the thread parameters of the male connector and the female connector include the tooth bottom arc radius, the tooth profile half angle, the taper and the pitch; the number of buckle turns and the tooth bottom arc radius, the tooth profile half angle, the taper and the pitch satisfy the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

12. The torsionally resistant drill pipe joint according to claim 11, characterized in that: The partial derivative of the number of make-up turns and the taper satisfies the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

13. The torsionally resistant drill pipe joint according to claim 11, characterized in that: The partial derivative of the number of thread turns and the radius of the tooth bottom arc satisfies the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

14. The torsionally resistant drill pipe joint according to claim 11, characterized in that: The partial derivative of the number of make-up turns and the pitch satisfies the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

15. The torsionally resistant drill pipe joint according to claim 11, characterized in that: The tooth bottom arc radius, the thread pitch, the tooth profile half angle and the taper satisfy the following relationship: ； Where θ is the tooth profile half angle, tpr is the taper, P is the pitch, R is the tooth bottom arc radius, and Rmax is the maximum value of the tooth bottom arc radius.

16. The torsionally resistant drill pipe joint according to claim 11, characterized in that: Each of the buckle types has a set range of buckle turns and a set range of torsional strength, the set range of the buckle turns is 5 turns to 13 turns, and the set range of torsional strength is not less than 10,000 ft-lbs.

17. The torsionally resistant drill pipe joint according to claim 11, characterized in that: The radius of the thread bottom arc of each of the male connector and the female connector in any buckle type ranges from 0.038in to 0.08in.

18. The torsionally resistant drill pipe joint according to claim 11, characterized in that: The thread profile half angle of each of the male connector and the female connector in any buckle type ranges from 27.5° to 44.5°.

19. The torsionally resistant drill pipe joint according to claim 11, characterized in that: The taper of each of the male connector and the female connector in any buckle type ranges from 1 / 16 to 1 / 6.

20. The torsionally resistant drill pipe joint according to claim 11, characterized in that: When the buckle type is a designed buckle type, the taper and the tooth bottom arc radius also satisfy the following corresponding relationship: when the taper is 1 / 16, the corresponding tooth bottom arc radius range is 0.05in~0.065in; when the taper is 1 / 12, the corresponding tooth bottom arc radius range is 0.04in~0.060in; when the taper is 1 / 10, the corresponding tooth bottom arc radius range is 0.045in~0.055in.

21. The torsionally resistant drill pipe joint according to claim 11, characterized in that: The pitch range of each of the male connector and the female connector in any buckle type is 0.250in-0.364in.

22. A drill pipe joint design method, characterized in that: include: Determine the setting range of the number of beading turns and the torsional strength of the designed buckle type according to the number of beading turns and the torsional strength of the standard buckle type and the special buckle type respectively; wherein the setting range corresponding to the number of beading turns of the designed buckle type is 5 turns to 13 turns, and the setting range corresponding to the torsional strength of the designed buckle type is not less than 10000 ft-lbs; Setting the thread parameters of the designed thread type, the thread parameters include the tooth bottom arc radius, taper, tooth profile half angle and pitch, and the tooth profile half angle and pitch are selected according to the number of beading turns and the range of torsional strength; Select the taper range of the series according to the number of make-up circles and the range of torsional strength; According to the relationship between the thread parameters and the number of make-up turns, a series range of tooth bottom arc radius corresponding to the taper range is obtained; The number of make-up circles and the tooth bottom arc radius, the tooth profile half angle, the taper and the pitch satisfy the following relationship: ； Where N is the number of thread turns, θ is the thread half angle, tpr is the taper, P is the thread pitch, and R is the thread bottom arc radius.

23. The drill rod joint design method according to claim 22, characterized in that: The taper and the tooth bottom arc radius also satisfy the following corresponding relationship: when the taper is 1 / 16, the corresponding tooth bottom arc radius range is 0.05in~0.065in; when the taper is 1 / 12, the corresponding tooth bottom arc radius range is 0.04in~0.060in; when the taper is 1 / 10, the corresponding tooth bottom arc radius range is 0.045in~0.055in.

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