A drill pipe coupling control method, a drill pipe decoupling control method and a drilling rig

Abstract

The application discloses a drill pipe connection control method, a drill pipe disconnection control method and a drilling machine. By comparing the actual displacement of the power head during the connection or disconnection process with the theoretical displacement calculated based on the thread parameters and the number of rotation (or reverse rotation) circles in real time, the advancing (or reverse lifting) and rotating (or reversing) actions of the power head are dynamically adjusted, and the timing of completing the connection or separating the disconnection is accurately judged in combination with multi-dimensional criteria such as the upper limit of the rotating pressure or displacement. The application effectively avoids the connection failure or thread damage caused by thread misconnection, false connection or over-tightening, significantly improves the reliability and consistency of the connection and disconnection process. At the same time, by introducing a target torque self-adaptive adjustment mechanism based on the connection and disconnection times and the wear state, the tightening torque control is further optimized, the abnormal wear of the thread pair is reduced, and the service life of the drill pipe and the joint is prolonged, thereby providing technical support for efficient and stable operation of the drilling machine under complex working conditions.

Description

Technical Field

[0001] This application relates to the field of drilling rigs, and in particular to a drill pipe coupling control method, a drill pipe uncoupling control method, and a drilling rig. Background Technology

[0002] The existing automatic shackle connection scheme for roller cone drills has a single judgment condition, which only uses the pushing displacement of the power head as the criterion. This method cannot ensure the tightness of the thread, and the quality of the shackle connection is poor, which can easily affect the thread. Summary of the Invention

[0003] This application aims to provide a drill pipe coupling control method, a drill pipe uncoupling control method, and a drilling rig, which can improve the reliability of coupling and uncoupling, reduce coupling wear, and extend the service life of the drill pipe.

[0004] In a first aspect, embodiments of this application provide a drill pipe coupling control method, applied to a drilling rig, the drilling rig including a power head and at least two drill pipes, the drill pipe coupling control method including: Obtain the thread interval length of the joint section of the two drill pipes and the initial power head position of the power head, as well as the current power head position, rotation pressure and number of rotations during the jointing process; The actual displacement is calculated based on the current power head position and the initial power head position. The theoretical displacement is calculated based on the thread interval length and the number of revolutions. If the difference between the actual displacement and the theoretical displacement is greater than a preset positive value, the control stops the propulsion of the power head and continues the rotation of the power head until the difference between the actual displacement and the theoretical displacement is less than the preset positive value, then the control continues the rotation and propulsion of the power head. If the difference between the actual displacement and the theoretical displacement is less than a preset negative value, the rotation speed of the power head is increased to rotate and propel until the difference between the actual displacement and the theoretical displacement is less than a preset positive value. Then, the rotation speed is restored and the rotation and propulsion of the power head are continued. If the difference between the actual displacement and the theoretical displacement is less than a preset positive value, and the rotational pressure is greater than a preset upper limit of pressure, the rotation and propulsion of the power head are stopped, and the connection is completed.

[0005] Secondly, embodiments of this application provide a drill pipe uncoupling control method, applied to a drilling rig, the drilling rig including a power head and at least two drill pipes, the drill pipe uncoupling control method including: Obtain the thread spacing length of the uncoupling section of the two drill pipes and the initial power head position of the power head, as well as the current power head position and number of reverse rotations during the uncoupling process; The actual displacement is calculated based on the current power head position and the initial power head position. The theoretical displacement is calculated based on the thread interval length and the number of reverse turns. If the difference between the actual displacement and the theoretical displacement is greater than a preset positive value, control stops the reverse lifting of the power head and continues the reverse rotation of the power head until the difference between the actual displacement and the theoretical displacement is less than the preset positive value, then control continues the reverse rotation and reverse lifting of the power head. If the difference between the actual displacement and the theoretical displacement is less than a preset negative value, control the increase of the reverse rotation speed of the power head to reverse and lift it until the difference between the actual displacement and the theoretical displacement is less than a preset positive value, then restore the reverse rotation speed and control the continued reverse and lifting of the power head. If the difference between the actual displacement and the theoretical displacement is less than a preset positive value, and the actual displacement is greater than the preset upper limit of displacement, the reverse rotation and lifting of the power head are stopped to complete the unhooking.

[0006] Thirdly, embodiments of this application provide a drilling rig for implementing the drill rod coupling control method described in the first aspect embodiment and the drill rod uncoupling control method described in the second aspect embodiment.

[0007] The drill pipe coupling control method, drill pipe uncoupling control method, and drilling rig of this application dynamically adjust the pushing (or lifting) and rotating (or reversing) actions of the power head by comparing the actual displacement of the power head during coupling or uncoupling with the theoretical displacement calculated based on thread parameters and the number of rotations (or reverse rotations) in real time. Combined with multi-dimensional criteria such as rotational pressure or upper displacement limit, the timing of coupling completion or uncoupling separation is accurately determined. This application effectively avoids connection failure or thread damage caused by incorrect threading, false threading, or over-tightening, significantly improving the reliability and consistency of the coupling and uncoupling process. Simultaneously, by introducing a target torque adaptive adjustment mechanism based on the number of coupling / uncoupling cycles and wear state, the tightening torque control is further optimized, reducing abnormal wear of the threaded pair, extending the service life of the drill pipe and joint, and providing technical support for the efficient and stable operation of the drilling rig under complex working conditions.

[0008] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing this application. Attached Figure Description

[0009] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart of a drill pipe coupling control method according to an embodiment of this application; Figure 2This is a flowchart of a drill pipe uncoupling control method according to an embodiment of this application. Detailed Implementation

[0010] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0011] In the description of this application, the use of terms such as "first," "second," etc., is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0012] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0013] In the description of this application, it should be noted that, unless otherwise explicitly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0014] The technical solution of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of this application, not all embodiments.

[0015] See Figure 1 , Figure 1 This is a flowchart of a drill pipe coupling control method according to an embodiment of this application. The drill pipe coupling control method is applied to a drilling rig, which includes a power head and at least two drill pipes. The drill pipe coupling control method includes, but is not limited to, steps S110 to S160: Step S110: Obtain the thread interval length of the joint section of the two drill pipes and the initial power head position, as well as the current power head position, rotation pressure and number of rotations during the jointing process; Step S120: Calculate the actual displacement based on the current position of the power head and the initial position of the power head; Step S130: Calculate the theoretical displacement based on the thread interval length and the number of revolutions; Step S140: If the difference between the actual displacement and the theoretical displacement is greater than a preset positive value, control to stop the advancement of the power head and continue the rotation of the power head until the difference between the actual displacement and the theoretical displacement is less than the preset positive value, then control to continue the rotation and advancement of the power head. Step S150: If the difference between the actual displacement and the theoretical displacement is less than a preset negative value, control the rotation speed of the power head to increase for rotation and propulsion until the difference between the actual displacement and the theoretical displacement is less than a preset positive value, then restore the rotation speed and control the power head to continue rotating and propulsing. In step S160, if the difference between the actual displacement and the theoretical displacement is less than a preset positive value, and the rotation pressure is greater than the preset pressure upper limit, control the rotation and propulsion of the power head to stop, and complete the connection.

[0016] In this embodiment, the actual displacement of the power head during the coupling process is compared in real time with the theoretical displacement calculated based on thread parameters and the number of rotations. The propulsion and rotation actions of the power head are dynamically adjusted, and multi-dimensional criteria such as rotational pressure are used to accurately determine the timing of coupling completion. This application effectively avoids connection failure or thread damage caused by incorrect threading, loose threads, or over-tightening, significantly improving the reliability and consistency of the coupling process.

[0017] In step S110 above, the thread interval length is the axial distance between adjacent thread teeth of the drill pipe coupling section. This parameter can be pre-stored in the control system or identified in real time by a sensor. The initial power head position is the reference position of the power head in the axial direction before the coupling action begins. It is usually collected and recorded by a displacement sensor at the moment of coupling start. The current power head position, rotation pressure, and number of rotations are monitored and obtained in real time by displacement sensors, pressure sensors, and encoders during the coupling process. The sampling frequency can be set according to the control accuracy requirements to ensure the timeliness and accuracy of the data.

[0018] In step S120 above, the actual displacement is the distance the power head advances axially from the initial position. It is calculated as the difference between the current position of the power head and the initial position of the power head. This displacement reflects the actual depth of the thread during the engagement process and is one of the key parameters for judging the thread engagement state.

[0019] In step S130 above, the theoretical displacement is derived based on the geometric characteristics of the thread and the relationship between rotational motion. The theoretical displacement is equal to the thread spacing length (i.e., pitch) multiplied by the number of revolutions during the engagement process. This theoretical value represents the axial feed that the thread should achieve under ideal conditions of no slippage and no deformation.

[0020] By comparing the actual displacement with the theoretical displacement in real time, it is possible to effectively identify abnormalities such as mis-threading, stripping, or jamming during the connection process.

[0021] In step S140 above, the difference between the actual displacement and the theoretical displacement is the actual displacement minus the theoretical displacement. When the difference between the actual displacement and the theoretical displacement is greater than a preset positive value, it indicates that the actual axial movement of the drill pipe exceeds the thread engagement length corresponding to the current rotation angle, meaning "more movement than rotation," and the thread is at risk of disengagement or damage. In the context of thread engagement, the main reasons for this situation are as follows: 1. Controlling synchronization deviation: When the thread is close to being fully engaged, the spindle has decelerated / stopped, but the power head feed mechanism continues to descend due to inertia or hydraulic control lag, causing the actual displacement to exceed the theoretical value.

[0022] 2. Excessive clearance in the thread fit, or the drill pipe's own weight pulling the power head down, causing the feed speed to exceed the thread engagement speed, resulting in idle stroke between the thread profiles.

[0023] 3. Extreme cases: The threaded end face is completely engaged (tightly locked in place), but the feed mechanism still forces the feed forward, causing the spindle to be passively rotated, or the encoder to lose pulses or detect abnormalities.

[0024] Positive deviation exceeding the threshold can easily cause thread stripping, tooth profile damage, and derailment. The system will immediately reduce the feed rate and match the rotation speed to ensure the synchronization of "how much rotation, how much travel" and protect the thread life.

[0025] In step S150 above, the difference between the actual displacement and the theoretical displacement is the actual displacement minus the theoretical displacement. When the difference between the actual displacement and the theoretical displacement is less than a preset negative value, it indicates that the spindle has rotated through the corresponding angle, but the actual axial movement of the drill pipe is insufficient, that is, "rotating more but moving less," and the thread insertion depth lags behind the rotation. In the context of thread engagement, the main reasons for this situation are as follows: 1. Misalignment or thread misalignment (early stage of random or incorrect threading): The thread crests collide with each other, making it impossible to screw in properly. The spindle spins freely or slips, and the actual feed cannot keep up with the rotation speed.

[0026] 2. The thread surface is corroded, has rock powder / debris adhering to it, or the thread profile is damaged, resulting in excessive screwing resistance and insufficient feed thrust of the power head to push the drill pipe forward synchronously.

[0027] 3. Feed mechanism failure: internal leakage in the hydraulic cylinder, slippage of the feed chain / rack, resulting in insufficient actual feed displacement output by the power head.

[0028] A negative deviation exceeding the threshold is a preliminary warning signal for thread slippage, hooking, or transmission slippage, detecting abnormalities earlier than torque alarms. The system will immediately increase the rotational speed to attempt correction, or decrease the rotational speed and increase the feed thrust to attempt correction. In severe cases, it will directly shut down the machine for protection to prevent complete damage to the threads.

[0029] In step S160 above, the difference between the actual displacement and the theoretical displacement is the actual displacement minus the theoretical displacement. When the difference between the actual displacement and the theoretical displacement is less than a preset positive value, it indicates that the rotary motion and axial feed are well matched, the thread engagement is normal, and it is within the allowable normal deviation range. If the rotary pressure is greater than the preset upper limit of pressure at this time, it indicates that the threaded pair has reached a fully tightened state, the axial resistance has increased significantly, and continuing to apply torque will lead to overload risk. This preset upper limit of pressure can be set according to the drill pipe material, thread specification, and historical connection data, and is usually slightly higher than the stable pressure value during the normal tightening stage. Once the rotary pressure exceeds this threshold, the control system immediately terminates the rotation and propulsion action of the power head to prevent thread plastic deformation, tooth crushing, or stress concentration at the connection due to overtightening, thereby ensuring that the connection quality meets engineering safety standards.

[0030] In practical applications, the aforementioned preset positive values, preset negative values, and preset pressure upper limits can all be dynamically adjusted according to the drill pipe type and equipment wear condition. For example, under high wear conditions, the displacement deviation tolerance can be appropriately relaxed to accommodate the actual situation of increased thread fit clearance; while in high-precision docking scenarios, the threshold can be tightened to improve connection consistency. In addition, the system can also build a self-learning model based on historical connection data to optimize the target torque and pressure thresholds online, further improving the adaptability and robustness of the control strategy.

[0031] In some implementations, the engagement process controls the power head to rotate and propel at a target torque value, the constraint formula for which the target torque value is: ; in, For the target torque value, To preset the base torque value, This is a compensation coefficient for the number of unloading operations. The number of times the pole is connected and disconnected. This is the wear compensation coefficient. This is the deviation between the average unhooking torque of the most recent preset number of unhooking processes and the preset standard unhooking torque.

[0032] In this embodiment, by introducing a target torque adaptive adjustment mechanism based on the number of disconnections and wear conditions, the tightening torque control is further optimized, abnormal wear of the threaded pair is reduced, and the service life of the drill pipe and joint is extended, providing technical support for the efficient and stable operation of the drilling rig under complex working conditions. If the historical average value of the drill pipe's disconnect torque is significantly lower than the standard value, it indicates that the thread is severely worn and the friction is insufficient. In this case, the torque of the current connection is appropriately increased to compensate for the loss of preload. If the historical average value of the drill pipe's disconnect torque is higher than the standard value, it indicates that the thread has slight deformation, jamming, or corrosion. In this case, the torque of the current connection is appropriately reduced to prevent excessive screwing and breakage. When the compensated torque exceeds the safety limit or the disconnect torque remains below the failure threshold, an alarm is issued and automatic operation is stopped.

[0033] In some implementations, the fastening process is divided into an initial tightening process, a main tightening process, and a final tightening process according to the length of the thread screwed in. The preset base torque value of the initial tightening process is less than the preset base torque value of the main tightening process, and the preset base torque value of the main tightening process is less than the preset base torque value of the final tightening process.

[0034] The initial tightening process is 0% to 10% of the fastening process, the main tightening process is 10% to 95% of the fastening process, and the final tightening process is 95% to 100% of the fastening process.

[0035] By setting different preset base torque values ​​at different engagement stages, it is possible to avoid thread alignment difficulties or tooth profile impact damage caused by excessive torque during the initial tightening stage. At the same time, it ensures that there is sufficient screwing thrust to overcome frictional resistance during the main tightening stage, and precisely controls the preload during the final tightening stage to prevent overload.

[0036] It should be noted that the corresponding stage divisions of the initial tightening process, the main tightening process, and the final tightening process, as well as the setting of the preset basic torque value, can be adjusted according to the actual situation and should not be regarded as a limitation of this application.

[0037] The compensation coefficient for the number of unloading operations mentioned above is a positive number, which increases with the number of unloading operations.

[0038] The average unhooking torque of the most recent preset number of unhooking processes is obtained through the following steps: After each unscrewing is completed, the peak torque during the unscrewing process is obtained; The average unhooking torque is calculated based on the peak torque of the most recent preset number of unhooking processes.

[0039] The above average unhooking torque is the average of the peak torque of the most recent preset number of unhooking processes.

[0040] The peak torque mentioned above is calculated based on the maximum slewing pressure.

[0041] It should be noted that the calculation relationship between slewing pressure and torque is existing technology known to those skilled in the art, and will not be elaborated here.

[0042] In some embodiments, prior to step S120, the drill pipe coupling control method further includes, but is not limited to, steps S101 to S103: Step S101: Calculate the pressure change rate based on the change in rotational pressure; Step S102: If the slewing pressure is less than the preset engagement pressure threshold and the pressure change rate is greater than the preset engagement pressure change rate threshold, control the power head to stop slewing and advancing, wait for the preset impact elimination waiting time, and then control the power head to reverse and lift to re-engage. Step S103: If the slewing pressure is greater than the preset meshing pressure threshold and the pressure change rate is greater than the preset meshing pressure change rate threshold, control the power head to stop slewing and advancing, and trigger an alarm signal.

[0043] Understandably, during a normal threading process, the male and female threads align, the threads increase smoothly, and the rotational pressure rises linearly and slowly, with the pressure change rate remaining within a small range. When misalignment occurs, the rotational pressure will exhibit a step-like spike, and the pressure change rate will increase significantly.

[0044] In steps S101 to S103 above, the rotational pressure in the rotary hydraulic circuit is periodically collected, and the pressure change rate is calculated by differentiation. Simultaneously, a preset engagement pressure threshold and a preset engagement pressure change rate threshold are obtained through testing. If the rotational pressure is less than the preset engagement pressure threshold and the pressure change rate is greater than the preset engagement pressure change rate threshold, a mis-engagement protection is triggered, forward rotation stops, hydraulic shock is eliminated after a delay, and then the system reverses and retracts. After reversing to the correct position, it re-enters the engagement stage. If the rotational pressure is greater than the preset engagement pressure threshold and the pressure change rate is greater than the preset engagement pressure change rate threshold, the system stops operating due to pressure exceeding the limit.

[0045] In some implementations, all status parameters during the control process can be viewed on the cab display screen, and step sequence prompts accompany the connection and disconnection process, allowing operators to observe the process status at any time.

[0046] See Figure 2 , Figure 2 This is a flowchart of a drill pipe uncoupling control method provided in one embodiment of this application. The drill pipe uncoupling control method is applied to a drilling rig, which includes a power head and at least two drill pipes. The drill pipe uncoupling control method includes, but is not limited to, steps S210 to S260: Step S210: Obtain the thread spacing length of the uncoupling section of the two drill pipes and the initial position of the power head, as well as the current position of the power head and the number of reverse rotations during the uncoupling process; Step S220: Calculate the actual displacement based on the current position of the power head and the initial position of the power head; Step S230: Calculate the theoretical displacement based on the thread interval length and the number of reverse turns; Step S240: If the difference between the actual displacement and the theoretical displacement is greater than a preset positive value, control to stop the reverse lifting of the power head and continue the reverse rotation of the power head until the difference between the actual displacement and the theoretical displacement is less than the preset positive value, then control to continue the reverse rotation and reverse lifting of the power head. Step S250: If the difference between the actual displacement and the theoretical displacement is less than a preset negative value, control the increase of the reverse rotation speed of the power head to reverse and lift until the difference between the actual displacement and the theoretical displacement is less than a preset positive value, restore the reverse rotation speed and control the power head to continue reversing and lifting. In step S260, if the difference between the actual displacement and the theoretical displacement is less than a preset positive value, and the actual displacement is greater than the preset upper limit of displacement, control the reverse rotation and lifting of the power head to complete the uncoupling.

[0047] In this embodiment, by comparing the actual displacement of the power head during the uncoupling process with the theoretical displacement calculated based on thread parameters and the number of reverse turns in real time, the reverse lifting and reversing actions of the power head are dynamically adjusted. Combined with multi-dimensional criteria such as the upper limit of displacement, the timing of uncoupling separation is accurately determined. This application effectively avoids connection failure or thread damage caused by incorrect threading, loose threads, or over-tightening, significantly improving the reliability and consistency of the uncoupling process.

[0048] In step S210 above, the thread interval length is the axial distance between adjacent thread teeth of the drill pipe coupling section. This parameter can be pre-stored in the control system or identified in real time by a sensor. The initial power head position is the reference position of the power head in the axial direction before the uncoupling action begins. It is usually collected and recorded by a displacement sensor at the moment of uncoupling start. The current power head position and number of rotations are monitored and obtained in real time by displacement sensors and encoders during the uncoupling process. The sampling frequency can be set according to the control accuracy requirements to ensure the timeliness and accuracy of the data.

[0049] In step S220 above, the actual displacement is the distance the power head pulls back axially from its initial position. It is calculated as the difference between the current position of the power head and the initial position of the power head. This displacement reflects the actual length of the thread that is unscrewed during the uncoupling process and is one of the key parameters for judging the thread engagement state.

[0050] In step S230 above, the theoretical displacement is derived based on the geometric characteristics of the thread and the relationship between rotational motion. The theoretical displacement is equal to the thread spacing length (i.e., pitch) multiplied by the number of rotations during the uncoupling process. This theoretical value represents the axial retraction amount that the thread should achieve under ideal conditions of no slippage and no deformation.

[0051] By comparing the actual displacement with the theoretical displacement in real time, it is possible to effectively identify abnormalities such as mis-threading, stripping, or jamming during the uncoupling process.

[0052] In step S240 above, the difference between the actual displacement and the theoretical displacement is the actual displacement minus the theoretical displacement. When the difference between the actual displacement and the theoretical displacement is greater than a preset positive value, it indicates that the actual axial movement of the drill pipe exceeds the thread engagement length corresponding to the current rotation angle, meaning "more movement than rotation," and the thread is at risk of disengagement or damage. In the context of uncoupling, the main reasons for this situation are as follows: 1. If the lifting speed of the power head is too fast, exceeding the linear speed of the thread turning out, the thread profile is forcibly pulled axially, causing axial movement, which can easily damage the thread tip.

[0053] 2. The spindle encoder loses pulses or has abnormal counting, which causes the calculated theoretical displacement to be smaller than expected, while the actual displacement appears to be larger than expected.

[0054] Positive deviation exceeding the threshold can easily cause thread stripping, tooth profile damage, and derailment. The system will immediately reduce the feed rate and match the rotation speed to ensure the synchronization of "how much rotation, how much travel" and protect the thread life.

[0055] In step S250 above, the difference between the actual displacement and the theoretical displacement is the actual displacement minus the theoretical displacement. When the difference between the actual displacement and the theoretical displacement is less than a preset negative value, it indicates that the spindle has rotated through the corresponding angle, but the actual axial movement of the drill pipe is insufficient, that is, "rotating more but moving less," and the thread insertion depth lags behind the rotation. In the context of thread engagement, the main reasons for this situation are as follows: 1. Thread seizing / sticking: The threaded contact surface sticks together, resulting in extremely high resistance to unscrewing. Even if the spindle reverses, the thread cannot be unscrewed smoothly, and the actual lifting displacement is severely delayed.

[0056] 2. Insufficient clamping force of the chuck: The lower drill rod rotates synchronously with the spindle, but the thread does not rotate relative to it, so there is no axial displacement, and the deviation will be significantly negative.

[0057] A negative deviation exceeding the threshold is a preliminary warning signal for thread slippage, hooking, or transmission slippage, detecting abnormalities earlier than torque alarms. The system will immediately increase the rotational speed to attempt correction, or decrease the rotational speed and increase the feed thrust to attempt correction. In severe cases, it will directly shut down the machine for protection to prevent complete damage to the threads.

[0058] In step S260 above, the difference between the actual displacement and the theoretical displacement is the actual displacement minus the theoretical displacement. When the difference between the actual displacement and the theoretical displacement is less than a preset positive value, it indicates that the reverse motion and axial reverse lifting are well matched, the thread engagement is normal, and it is within the allowable normal deviation range. If the actual displacement is greater than the preset upper limit of displacement, it indicates that the threads of the two drill pipes have completely disengaged, and the axial separation distance has reached or exceeded the preset safe unpinning stroke. This preset upper limit of displacement is usually set according to the effective engagement length of the drill pipe threads, and is generally slightly greater than the displacement required for complete theoretical unpinning (for example, 105%~110% of the total thread length) to ensure that the joint is completely separated and to avoid accidental jamming or secondary engagement during subsequent drilling due to residual engagement. Once the actual displacement exceeds this threshold, the control system determines that the unpinning is complete and immediately stops the reverse and reverse lifting actions of the power head to prevent unnecessary impact or wear on the equipment and drill tools caused by idling or excessive lifting.

[0059] In practical applications, the aforementioned preset positive values, preset negative values, and preset pressure upper limits can all be dynamically adjusted according to the drill pipe type and equipment wear condition. For example, under high wear conditions, the displacement deviation tolerance can be appropriately relaxed to accommodate the actual situation of increased thread fit clearance; while in high-precision docking scenarios, the threshold can be tightened to improve connection consistency.

[0060] During the aforementioned uncoupling process, the system can also use the trend of rotational pressure changes to help determine the uncoupling status. For example, during the normal uncoupling phase, as the thread gradually loosens, the rotational pressure should show a slow downward trend; if a sudden drop in pressure or abnormal fluctuations occur in the early stages of uncoupling, it may indicate that the thread has disengaged prematurely or is stuck. In this case, the corresponding protection logic can be triggered, such as pausing the operation and performing a status check.

[0061] In some implementations, the target power head position and the current power head position are used to determine whether to automatically advance or automatically reverse, and PID control is performed on the advance flow or reverse flow based on the current power head position and a preset flow value.

[0062] This application also provides a drilling rig for implementing the drill rod coupling control method of the first aspect embodiment and the drill rod uncoupling control method of the second aspect embodiment, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0063] It should be understood that the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in this application, and such modifications or substitutions should be covered within the scope of protection of this application.

Claims

1. A drill pipe coupling control method, applied to a drilling rig, the drilling rig comprising a power head and at least two drill pipes, characterized in that, The drill pipe connection control method includes: Obtain the thread interval length of the joint section of the two drill pipes and the initial power head position of the power head, as well as the current power head position, rotation pressure and number of rotations during the jointing process; The actual displacement is calculated based on the current power head position and the initial power head position. The theoretical displacement is calculated based on the thread interval length and the number of revolutions. If the difference between the actual displacement and the theoretical displacement is greater than a preset positive value, the control stops the propulsion of the power head and continues the rotation of the power head until the difference between the actual displacement and the theoretical displacement is less than the preset positive value, then the control continues the rotation and propulsion of the power head. If the difference between the actual displacement and the theoretical displacement is less than a preset negative value, the rotation speed of the power head is increased to rotate and propel until the difference between the actual displacement and the theoretical displacement is less than a preset positive value. Then the rotation speed is restored and the rotation and propulsion of the power head are continued. If the difference between the actual displacement and the theoretical displacement is less than a preset positive value, and the rotational pressure is greater than a preset upper limit of pressure, the rotation and propulsion of the power head are stopped, and the connection is completed.

2. The drill pipe coupling control method according to claim 1, characterized in that, The latching process controls the power head to rotate and propel at a target torque value, and the constraint formula for the target torque value is: ； in, The target torque value, To preset the base torque value, This is a compensation coefficient for the number of unloading operations. The number of times the pole is connected and disconnected. This is the wear compensation coefficient. This is the deviation between the average unhooking torque of the most recent preset number of unhooking processes and the preset standard unhooking torque.

3. The drill pipe joint control method according to claim 2, characterized in that, The average unhooking torque of the most recent preset number of unhooking processes is obtained through the following steps: After each unscrewing is completed, the peak torque during the unscrewing process is obtained; The average unhooking torque is calculated based on the peak torque of the most recent preset number of unhooking processes.

4. The drill pipe joint control method according to claim 3, characterized in that, The peak torque is calculated based on the maximum slewing pressure.

5. The drill pipe joint control method according to claim 2, characterized in that, The fastening process is divided into an initial tightening process, a main tightening process, and a final tightening process according to the length of the screw-in thread. The preset basic torque value of the initial tightening process is less than the preset basic torque value of the main tightening process, and the preset basic torque value of the main tightening process is less than the preset basic torque value of the final tightening process.

6. The drill pipe joint control method according to claim 5, characterized in that, The initial tightening process accounts for 0% to 10% of the fastening process, the main tightening process accounts for 10% to 95% of the fastening process, and the final tightening process accounts for 95% to 100% of the fastening process.

7. The drill pipe joint control method according to claim 1, characterized in that, Before calculating the actual displacement based on the current power head position and the initial power head position, the drill pipe coupling control method further includes: Calculate the pressure change rate based on the change in the rotary pressure; If the rotational pressure is less than the preset engagement pressure threshold and the pressure change rate is greater than the preset engagement pressure change rate threshold, the power head is controlled to stop rotating and advancing. After waiting for a preset impact elimination waiting time, the power head is controlled to reverse and lift to re-engage.

8. The drill pipe joint control method according to claim 7, characterized in that, After calculating the pressure change rate based on the change in rotary pressure, the drill pipe coupling control method further includes: If the rotational pressure is greater than a preset engagement pressure threshold and the pressure change rate is greater than a preset engagement pressure change rate threshold, the power head is controlled to stop rotating and advancing, and an alarm signal is triggered.

9. A drill pipe uncoupling control method, applied to a drilling rig, the drilling rig including a power head and at least two drill pipes, characterized in that, The drill pipe uncoupling control method includes: Obtain the thread spacing length of the uncoupling section of the two drill pipes and the initial power head position of the power head, as well as the current power head position and number of reverse rotations during the uncoupling process; The actual displacement is calculated based on the current power head position and the initial power head position. The theoretical displacement is calculated based on the thread interval length and the number of reverse turns. If the difference between the actual displacement and the theoretical displacement is greater than a preset positive value, control stops the reverse lifting of the power head and continues the reverse rotation of the power head until the difference between the actual displacement and the theoretical displacement is less than the preset positive value, then control continues the reverse rotation and reverse lifting of the power head. If the difference between the actual displacement and the theoretical displacement is less than a preset negative value, control the increase of the reverse rotation speed of the power head to reverse and lift it until the difference between the actual displacement and the theoretical displacement is less than a preset positive value, then restore the reverse rotation speed and control the continued reverse and lifting of the power head. If the difference between the actual displacement and the theoretical displacement is less than a preset positive value, and the actual displacement is greater than the preset upper limit of displacement, the reverse rotation and lifting of the power head are stopped to complete the unhooking.

10. A drilling rig, characterized in that, The drilling rig is used to implement the drill pipe coupling control method as described in any one of claims 1 to 8, and the drill pipe uncoupling control method as described in claim 9.

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