A constant load clamp device for a coiled tubing injector head and method of designing the same

Abstract

The application is suitable for the field of mechanical device clamping, and relates to a constant load clamping device for a coiled tubing drilling machine injection head, characterized in that the device comprises a sheet-cable structure, two ends of the sheet-cable structure are connected with a first connecting piece and a second connecting piece, the sheet-cable structure is symmetrically provided with a first sheet and a second sheet, the first sheet and the second sheet are arranged in parallel, one cable is arranged between the first sheet and the second sheet, one end of the first sheet, one end of the second sheet and one end of the cable are fixed to a first fixed position of the first connecting piece, the other end of the first sheet, the other end of the second sheet and the other end of the cable are fixed to a second fixed position of the second connecting piece, and the sheet-cable structure enables the clamping device to have the characteristics of high static and low dynamic and good vibration isolation.

Description

Technical Field

[0001] This invention belongs to the field of mechanical device clamping, and particularly relates to a constant load clamping device for the injection head of a continuous tubing drill and its design method. Background Technology

[0002] The injection head mainly consists of a frame, hydraulic motor, counting gear, coiled tubing slips, traction chain, tensioning device, clamping device, idler wheel, and load sensor. The frame's primary function is to mount and secure the sprockets, hydraulic motor, clamping device, and other accessories on the injection head. The hydraulic motor provides power for driving the chain and coiled tubing transport. The tensioning and clamping devices primarily tension the chain and drive the slips to grip the coiled tubing. The counting gear measures the length of the coiled tubing inserted. The load sensor primarily measures drilling pressure. Typically, the inner diameter of the slips on the outer side of the chain matches the outer diameter of the coiled tubing, used to clamp the coiled tubing and move it up and down along with the drive chain.

[0003] Foreign countries have a longer history of developing coiled tubing equipment, and their technology is more mature and advanced. Major foreign companies producing coiled tubing injection heads include NOV Hydra Rig, Stewart & Stevenson (S&S), and ASEP. S&S's D-series injection heads feature a specially designed "floating" tensioning system with automatic tensioning, enabling ultra-low speeds. They are suitable for coiled tubing sizes ranging from 25.4 mm (1 inch) to 114.3 mm (4.5 inches) in diameter. ASEP's 363KN four-wheel drive K-COIL Quad-Head 80H injection head is only half the size of similar products. This injection head uses a four-chain drive design, which increases the lifting force of the injection head and significantly reduces the damage to the coiled tubing caused by injection head clamping marks.

[0004] However, the traditional solution that uses a hydraulic cylinder as the injection head to achieve the clamping function is complex in structure and requires the injection head to implement additional control over the cylinder to ensure that the continuous tube is stably clamped, which poses a certain risk of failure during operation. Summary of the Invention

[0005] The purpose of this application is to provide a constant load clamping device for the injection head of a coiled tubing drilling rig and its design method. The aim is to solve the problem that the traditional solution of using a hydraulic cylinder to achieve the clamping function of the injection head is structurally complex and requires the injection head to implement additional control over the hydraulic cylinder to ensure that the coiled tubing is stably clamped, which poses a certain risk of failure during operation.

[0006] This application embodiment is implemented as follows: a constant load clamping device for the injection head of a coiled tubing drilling rig, the device comprising:

[0007] A sheet-and-cable structure, wherein a first connector and a second connector are connected to both ends of the sheet-and-cable structure;

[0008] The sheet-cable structure has a first sheet and a second sheet arranged symmetrically, the first sheet and the second sheet are arranged in parallel, and a cable is arranged between the first sheet and the second sheet. One end of the first sheet, one end of the second sheet and one end of the cable are fixed to a first fixed position of the first connector, and the other end of the first sheet, the other end of the second sheet and the other end of the cable are fixed to a second fixed position of the second connector.

[0009] Another objective of this application is to provide a design method for a constant load clamping device for the injection head of a coiled tubing drilling rig, the method comprising the following steps:

[0010] Establish a dynamic model of the clamping device;

[0011] Based on the dynamic model, the generalized coordinate vector of the dynamic model, as well as the total kinetic energy and total potential energy of the model are obtained;

[0012] The generalized force of the generalized coordinate vector is calculated by using the Lagrange multipliers and the gradient of the constraint condition with respect to the generalized coordinate vector, and the contribution of the constraint condition to the generalized force is obtained.

[0013] Based on the generalized force, the constraint conditions contributing to the generalized force, and the constraint conditions of the generalized coordinate vector, the dynamic equations of the model are obtained.

[0014] By introducing notation, the system of dynamic equations can be written in the general form of differential-algebraic equations.

[0015] The differential algebraic equation is solved iteratively using the backward difference method to obtain the motion trajectory and deformation state information of the clamping device.

[0016] This application provides a constant load clamping device for the injection head of a coiled tubing drilling rig. The device's performance is evaluated using a time-domain simulation based on a parameterized, precisely described dynamic model. A trust region constraint algorithm is combined to implement the device's dynamic design, resulting in excellent dynamic performance that meets the overall design requirements of the injection head. A simple "sheet-cable" structure achieves reliable constant force clamping, preventing damage to the coiled tubing due to excessive load. Furthermore, the device's high static and low dynamic characteristics provide vibration isolation, thereby extending the service life of the injection head. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the clamping device provided in the embodiments of this application;

[0018] Figure 2This is a schematic diagram showing the initial state and the deformed state of the clamping device provided in the embodiments of this application.

[0019] Figure 3 A schematic diagram of the clamping device provided in the embodiments of this application installed on a chain roller system;

[0020] Figure 4 A simplified model diagram for verifying the constant force clamping and vibration isolation performance of the clamping device provided in the embodiments of this application;

[0021] Figure 5 A diagram showing the relationship between restoring force, dynamic stiffness, unilateral clamping force, and displacement of the clamping device provided in the embodiments of this application under clamping conditions;

[0022] Figure 6 Frequency response curve of the double-layer series clamping device provided in the embodiments of this application;

[0023] Figure 7 A diagram showing the installation position of the clamping device provided in the embodiments of this application on a coiled tubing drilling rig;

[0024] Figure 8 A clamping force curve diagram of the chain roller system on both sides of the clamping device provided in the embodiments of this application;

[0025] Figure 9 The time-domain curve of the lateral displacement of the drilling rig provided in the embodiments of this application;

[0026] Figure 10 A calculation flowchart of the dynamic design method for the clamping device provided in the embodiments of this application;

[0027] Figure 11 A flowchart illustrating the differential algebraic equation solving method for the dynamic design of the clamping device provided in this application embodiment;

[0028] Figure 12 A rigid body element schematic diagram of the dynamic design method of the clamping device provided in the embodiments of this application;

[0029] Figure 13 A schematic diagram of a two-node Lagrange beam element for the dynamic design method of the clamping device provided in the embodiments of this application;

[0030] Figure 14 A schematic diagram of a two-node Lagrange element for the dynamic design method of the clamping device provided in the embodiments of this application;

[0031] Figure 15 A load-displacement curve of the clamping device under a certain design parameter in the dynamic design method of the clamping device provided in the embodiment of this application;

[0032] Figure 16The optimization process diagram of the average working load, working interval length, and maximum normal stress of the clamping device provided in the embodiments of this application is shown.

[0033] Figure 17 A graph showing the relationship between restoring force, dynamic stiffness, and displacement of the clamping device obtained by optimizing the dynamic design method of the clamping device provided in the embodiments of this application;

[0034] Wherein: 1. First connector; 2. Second connector; 3. First sheet; 4. Second sheet; 5. Cable. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0036] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various elements, but unless otherwise stated, these elements are not limited by these terms. These terms are used only to distinguish one element from another.

[0037] like Figure 1 As shown, in one embodiment, a constant load clamping device for the injection head of a coiled tubing drill rig is provided, the device comprising:

[0038] A sheet-and-cable structure, wherein the two ends of the sheet-and-cable structure are connected by a first connector 1 and a second connector 2;

[0039] In the sheet-cable structure, a first sheet 3 and a second sheet 4 are symmetrically arranged, and the first sheet 3 and the second sheet 4 are arranged in parallel. A cable 5 is arranged between the first sheet 3 and the second sheet 4. One end of the first sheet 3, one end of the second sheet 4 and one end of the cable 5 are all fixed at a first fixed position of the first connector 1. The other end of the first sheet 3, the other end of the second sheet 4 and the other end of the cable 5 are all fixed at a second fixed position of the second connector 2.

[0040] In this embodiment, as Figure 1 and Figure 2The sheet-cable structure shown consists of straight, thin sheets initially in a buckled state at both ends, connected by a cable at the middle to apply prestress and maintain the buckled state. Axial displacement is applied to one end of the structure, causing it to move towards the other end. During this process, because the sheets on both sides are in a buckled state and the cable in the middle cannot withstand pressure, the driving force remains essentially constant, achieving constant force clamping while maintaining low dynamic stiffness. Furthermore, to achieve higher static load-bearing capacity to meet the requirements of high injection force and pull-out force under extreme conditions, two sets of the aforementioned sheet-cable structures are installed side-by-side. Figure 2 As shown, when the deformation of the middle thin plates reaches a certain degree, they will come into contact with each other, which further increases the axial support force.

[0041] The clamping device operates in three stages. Before deformation, prestress is provided by cables, causing the sheet to buckle. During deformation, the sheet continues to deform under the influence of axial displacement. At this point, the axial stiffness of the structure remains almost constant, i.e., the dynamic stiffness is almost zero, achieving a constant force clamping effect. Finally, when the two sheets in the middle further deform, they come into contact, increasing the axial stiffness of the clamping device and providing greater static stiffness, achieving a high static and low dynamic stiffness effect. It can be operated by fixing one end to the injection head frame and the other end to the upper injection head base. Two clamping devices are installed on each side of the frame, for a total of four. Figure 3 As shown.

[0042] In this embodiment, a simplified clamping model is established by combining the above-mentioned constant force clamping device with the mass block, such as... Figure 4 As shown, the simplified model consists of four clamping devices and one mass block. The mass block simulates the overall mass of the drilling rig. The two clamping devices on the left and two on the right simulate the design of a double-layer parallel installation of the chain roller system clamping devices. Dynamic time-domain simulations were performed using the simplified model to verify the constant-force clamping and vibration isolation performance of the clamping devices designed in this application.

[0043] Based on the installation method of 16 sets of clamping devices in each of the upper and lower rows, the mass of the mass block is taken as 1 / 32 of the total mass of the drilling rig (11500 kg). First, the mass block applies a 4 mm displacement to the outermost connector towards the center to simulate the clamping process of the chain roller system. Then, a certain displacement X is applied to the middle connector to simulate the lateral movement of the continuous pipe in the middle, and the constant force clamping and vibration isolation performance are verified respectively.

[0044] The mass block is fixed to the ground, and a quasi-static displacement of ±4 mm is applied to the middle connector using the STEP function as shown in the following formula, with an average moving speed of 0.4 mm / s.

[0045]

[0046] The performance of the clamping device under constant force clamping was verified, and the results of restoring force and dynamic stiffness were obtained as follows: Figure 5 As shown, when both sides are in the clamping state, the restoring force of the clamping device near the equilibrium position is basically zero, and the dynamic stiffness is relatively small, with the clamping force of the chain rollers on both sides remaining around 1.24kN. When the working range [-2m, 2m] is exceeded, the restoring force increases sharply, and the clamping force of the chain roller on one side also increases rapidly, providing nearly three times the static load-bearing capacity near the equilibrium position. These characteristics meet the design goals of constant force clamping and high static and low dynamic vibration isolation.

[0047] The mass block was connected to the ground using a sliding pair. Simple harmonic vibrations with a frequency of 0.1Hz-10Hz and an amplitude of 0.5mm-2.0mm were applied to the central connecting part to simulate the lateral vibration of the continuous pipe held in the middle during drilling rig operation. The vibration isolation performance of the clamping device was verified, and the frequency response curves were obtained as follows: Figure 6 As shown.

[0048] As the displacement transmissibility increases with amplitude, the isolation frequency of the system increases, and the frequency response curve bends to the right. This indicates that the structure is a gradually stiffening nonlinear system, and the influence of amplitude on vibration isolation performance needs to be considered during design. When the excitation amplitude is less than 1 mm, the structure has an isolation effect on vibrations with frequencies greater than 1.2 Hz. If the excitation frequency exceeds 2 Hz, the vibration isolation efficiency will exceed 50%.

[0049] In one embodiment, the aforementioned constant force clamping device is designed with a double-layer parallel connection and 16 sets of parallel connections. It is installed on the drilling rig's chain roller system for full-model drilling and vibration time-domain simulation. A full model of a continuous casing drilling rig applied to horizontal boreholes is shown below. Figure 7 As shown.

[0050] The outer diameter of the central continuous tube is set to 2-7 / 8 inches, and the orifice diameter to 4 inches. The trajectory measurement parameters are set at a 10° inclination angle at a depth of 0 meters and a 10° inclination angle at a depth of 100 meters. The displacement of the central extrusion plate is set to 23 mm, ensuring the chain clamping block is holding the central continuous tube. After 5 seconds, the speed of the drive wheel is gradually increased to 0.1 rad / s, causing the chain to drive the continuous tube forward. During this process, the clamping force provided by the chain roller system on both sides is as follows: Figure 8 As shown, after entering the clamping condition, the clamping force of the chain roller system on both sides remains basically constant at around 40kN, and is the same on both sides. It can be seen that this clamping device can meet the requirements of constant load during drilling.

[0051] Next, the drilling rig is connected to the ground using a sliding pair. For the first 5 seconds, the two side clamping plates of the chain roller system are moved 23mm towards the center to clamp the continuous tube. Then, a simple harmonic vibration with a frequency of 10Hz and an amplitude of 0.5mm is applied to the central continuous tube to simulate the lateral vibration of the clamped continuous tube during drilling operation. The time-domain curve of the drilling rig's lateral displacement is obtained as follows: Figure 9 As shown, under an external excitation frequency of 2Hz, the lateral displacement amplitude of the drilling rig tends to be below 0.2mm, which is relatively small compared to the 0.5mm amplitude of the external excitation, resulting in a vibration isolation efficiency exceeding 50%. When the external excitation frequency increases to 10Hz, the amplitude remains below 0.04mm and continues to attenuate, with a displacement transmissibility of less than 0.1, meaning the vibration isolation efficiency exceeds 90%. In summary, this clamping device demonstrates excellent isolation performance for vibrations with frequencies above 2Hz and amplitudes below 0.5mm.

[0052] like Figure 10 As shown, in one embodiment, a design method for a constant load clamping device for the injection head of a coiled tubing drill rig is proposed, which may specifically include the following steps:

[0053] Step S102: Establish the dynamic model of the clamping device;

[0054] Step S104: Based on the dynamic model, obtain the generalized coordinate vector of the dynamic model, as well as the total kinetic energy and total potential energy of the model;

[0055] Step S106: Calculate the generalized force of the generalized coordinate vector by using the Lagrange multipliers and the gradient of the constraint condition with respect to the generalized coordinate vector to obtain the generalized force contributed by the constraint condition.

[0056] Step S108: Based on the generalized force, the constraint conditions contributing to the generalized force, and the constraint conditions of the generalized coordinate vector, the dynamic equations of the model are obtained.

[0057] Step S110: Introduce notation and write the set of dynamic equations into a general form of differential-algebraic equations;

[0058] Step S112: The differential algebraic equation is solved iteratively using the backward difference method to obtain the motion trajectory and deformation state information of the clamping device.

[0059] In this embodiment, during dynamic analysis, the dynamic model is generally divided into multiple small units. The force state of each unit is analyzed, and all generalized coordinates of each unit in the dynamic model are listed together to form the generalized coordinate vector of the model:

[0060]

[0061] Next, list all the constraints on the generalized coordinate vector of the model:

[0062] ,

[0063] Then, the kinetic and potential energies of each unit in the model are summed to obtain the total kinetic energy of the system. Total potential energy Simultaneously, the active forces acting on the model and the generalized forces corresponding to each generalized coordinate caused by all contacts are calculated. Then it can be done through Lagrange multipliers gradient of constraints with respect to generalized coordinates By obtaining the generalized forces contributing to the constraints, we finally arrive at the first kind of Lagrange equations for the model:

[0064]

[0065] The dynamic equations of the model can be further expressed in the following matrix form:

[0066]

[0067] Introduction notation , To write the above expression in a more general form:

[0068]

[0069] In the formula , yes Regarding time The first and second derivatives.

[0070] This is a typical set of time-varying nonlinear differential algebraic equations (DAEs). The backward difference formula (BDF) can be used to solve these equations to obtain the transient time history response of the clamping device dynamic model during a wide range of motion, thereby obtaining information such as motion trajectory and deformation state.

[0071] In this embodiment, the numerical integration process for solving differential algebraic equations is as follows:

[0072] Step S202: Select the step size and integration order;

[0073] Step S204: Determine the nonlinear equation system;

[0074] Step S206: Solve iteratively using the backward difference method;

[0075] Step S208: Determine whether the iteration precision meets the preset value;

[0076] If the iteration accuracy meets the preset value, then step S210 determines whether the integration accuracy meets the preset value.

[0077] If the iteration accuracy does not meet the preset value, step S212 determines whether the maximum number of iterations has been reached;

[0078] If the maximum number of iterations is reached, step S214 reduces the step size and returns to step S202; if the maximum number of iterations is not reached, it returns to step S206.

[0079] If the integration accuracy meets the preset value, proceed to step 216 for the next time step; if the integration accuracy does not meet the preset value, execute step S214 to reduce the step size and return to step S202.

[0080] In one embodiment, the clamping device consists of a "sheet-cable" structure, and multiple sheets-cable structures can be set. The two ends of the sheet-cable structure are connected to long strip-shaped connectors to ensure that the axial displacement of each "sheet-cable" structure is synchronized. The sheet is modeled using Lagrange beam elements, and its cross-section is designed as a rectangle. The cable is modeled using large deformation cable elements and can only bear tensile loads. The long strip-shaped components at both ends are modeled as rigid bodies, that is, it is assumed that deformation only occurs in the part composed of the middle sheet and cable.

[0081] In one embodiment, such as Figure 12 As shown, the long strip-shaped connecting parts at both ends in the dynamic model of the clamping device are modeled as rigid bodies, and generalized coordinates are selected. ,in Indicates the location of the center of mass of the rigid body. The attitude of a rigid body, its generalized velocity and acceleration can be expressed as:

[0082]

[0083] The angular velocity and angular acceleration of a rigid body in the local coordinate system can be expressed as:

[0084]

[0085] In the formula It is the transformation matrix for any rotation vector.

[0086]

[0087] In the formula , yes The corresponding antisymmetric matrix. The generalized inertial force of a rigid body can be expressed as:

[0088]

[0089] In the formula It is the principal moment of inertia tensor of a rigid body in a local coordinate system.

[0090] In summary, the equations of rigid body dynamics can be obtained.

[0091]

[0092] In the formula and These are the generalized external forces and generalized constraint forces acting on a rigid body.

[0093] In one embodiment, such as Figure 13 As shown, the thin sheet in the dynamic model of the clamping device is modeled using Timoshenko beam elements based on the Lagrange method, and its generalized coordinates are:

[0094]

[0095] The generalized inertial force of a beam element can be expressed as:

[0096]

[0097] in , , These represent the beam's density, cross-sectional area, and length, respectively. and Let represent the shape functions in translational and rotational coordinates, respectively. The generalized elastic force of a beam element can be expressed as:

[0098]

[0099] in and Let these represent the strain vector of the beam element and its corresponding internal force. and These represent the bending vector of the beam element and its corresponding internal force.

[0100] In summary, the dynamic equations of the beam element can be obtained.

[0101]

[0102] In the formula and These are the generalized external forces and generalized constraint forces acting on the beam element.

[0103] In one embodiment, such as Figure 14As shown, the cable in the dynamic model of the clamping device is modeled using a large deformation flexible cable element based on the Lagrange method. The three-dimensional flexible cable in space only undergoes translation in three directions. Therefore, the cable configuration is determined by determining the positions of the nodes at both ends of the centerline of the cable element. Its generalized coordinates are taken as...

[0104]

[0105] The generalized inertial force of a cable element can be expressed as:

[0106]

[0107] in These represent the density, cross-sectional area, and length of the cable, respectively. The shape function representing the translational coordinates. The generalized elastic force of the cable element can be expressed as:

[0108]

[0109] in This represents the tensile strain of the cable element. and These are the Young's modulus and cross-sectional area of ​​the cable, respectively. It is a coefficient used to represent the tensile strength of a cable, i.e.

[0110]

[0111] In summary, the dynamic equations of the cable element can be obtained.

[0112]

[0113] In the formula and These are the generalized external forces and generalized constraint forces acting on the cable element.

[0114] In one embodiment, the design parameters in the dynamic model of the clamping device include: the span length, span height, width, thickness of the sheet, and the number of sheet units; the length and diameter of the cable; the distance between the strip-shaped connectors, and the height and width of the strip-shaped connectors.

[0115] In this embodiment, the span of the sheet is specified as a fixed value. The design parameters that can be changed include: the width and thickness of the sheet, and the installation distance between the two sets of sheet-cable structures. The design objective function is as follows:

[0116]

[0117] in, , These represent the weights of average working load and working interval length, respectively. , and These represent the average working load, the working interval length, and the width of the sheet, respectively. , sheet thickness Installation distance The functions relating these relationships are all derived from dynamic simulations. , and These are the target values ​​for average working load, working interval length, and maximum normal stress of the sheet, respectively.

[0118] The above formula also includes restrictions on the range of variation of the independent variable; therefore, this problem belongs to bounded constraint optimization. A trust region constraint algorithm is used to optimize and solve the above objective function. The Jacobi matrix and Hessen matrix are calculated using the BFGS method. For example, as shown... Figure 15 As shown, taking the load-displacement curve of a certain calculation result as an example, the working interval length is the length of the area where the load change is relatively gradual, and the average working load is the average value of the load within this interval. This application adopts a design of series installation of a double-layer device, which can provide a larger overall working interval length under the premise that the thin sheet bears relatively small normal stress. Finally, to facilitate maintenance and replacement, the device is further divided into 16 groups for parallel installation.

[0119] In this embodiment, for example, the target average working load of a single sheet-cable structure is set at 1250 N, the target working interval length is 0.003 mm, and the target maximum normal stress is 1000 MPa. The initial design parameters are as follows:

[0120] The sheet has a span length of 0.1m, a span height of 0.005m, a width of [0.01m, 0.11m], a thickness of [0.0001m, 0.0023m], 20 sheet units, a cable length of 0.1m, a cable diameter of 0.002m, an installation distance of [0.025m, 0.135m] between two sets of "sheet-cable", a connector height (x-direction) of 2.5 times the installation distance, and a connector width (z-direction) of [0.01m, 0.11m].

[0121] Both the sheet and the cable are made of the same material with a density of 7850.89 kg / m³. 3 The elastic modulus is 206.84 GPa, and the Poisson's ratio is 0.3. The weighting parameters are all taken as the reciprocal of the target value in the same unit system. , , The optimization process is as follows: Figure 16 As shown.

[0122] The optimization process involved 50 iterations and 200 dynamic simulations. The blue line in the left-hand graph represents the corresponding target value. Figure 16As can be seen, after 30 iterations, the average working load and working range length have approached the target values ​​of 1.25 kN, 0.003 mm, and 1000 MPa, respectively. The optimal sheet width in each iteration is 66.93 mm, the optimal installation distance is 24.54 mm, and the optimal sheet thickness is 0.4056 mm. The optimized clamping device's restoring force-displacement curve and stiffness-displacement curve within the working range are shown below. Figure 17 As shown, the dynamic stiffness Discrete restoring force For displacement The following difference was obtained

[0123]

[0124] Depend on Figure 17 As can be seen, the clamping device has a basically constant restoring force within the displacement range of 0-3mm. The average restoring force is defined as the area enclosed by the restoring force and displacement from the start to the end of the working range, divided by the length of the working range. The average restoring force of the clamping device is 1.24kN. When the displacement exceeds 3mm, the restoring force of the structure increases sharply. This higher static bearing capacity can provide a higher clamping force.

[0125] It should be understood that although the steps in the flowcharts of the various embodiments of this application are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in each embodiment may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps.

[0126] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0127] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for a constant load clamping device for the injection head of a continuous tubing drilling rig, characterized in that, The device includes: A sheet-and-cable structure, wherein a first connector and a second connector are connected to both ends of the sheet-and-cable structure; The sheet-cable structure is provided with a first sheet and a second sheet symmetrically arranged, the first sheet and the second sheet are arranged in parallel, and a cable is provided between the first sheet and the second sheet. One end of the first sheet, one end of the second sheet and one end of the cable are all fixed to a first fixed position of the first connector, and the other end of the first sheet, the other end of the second sheet and the other end of the cable are all fixed to a second fixed position of the second connector. The method includes the following steps: Establish a dynamic model of the clamping device; Based on the dynamic model, the generalized coordinate vector of the dynamic model, as well as the total kinetic energy and total potential energy of the model are obtained; The generalized force of the generalized coordinate vector is calculated by using the Lagrange multipliers and the gradient of the constraint condition with respect to the generalized coordinate vector, and the contribution of the constraint condition to the generalized force is obtained. Based on the generalized force, the constraint conditions contributing to the generalized force, and the constraint conditions of the generalized coordinate vector, the dynamic equations of the model are obtained. By introducing notation, the system of dynamic equations can be written in the general form of differential-algebraic equations. The differential algebraic equation is solved iteratively using the backward difference method to obtain the motion trajectory and deformation state information of the clamping device.

2. The design method of a constant load clamping device for the injection head of a coiled tubing drilling rig according to claim 1, characterized in that, The dynamic model of the clamping device is as follows: The first and second connectors are based on rigid body elements, and a dynamic model of the rigid body elements is established. The first and second thin sheets are based on Timoshenko beam elements, and a dynamic model of the beam elements is established. Based on the large deformation flexible cable element, a dynamic model of the cable element is established.

3. The design method of a constant load clamping device for the injection head of a coiled tubing drilling rig according to claim 1, characterized in that, The design parameters of the dynamic model of the clamping device include: The span length, span height, width, thickness, and number of thin-slice units; The length and diameter of the cable; The distance between the connectors, the height of the connectors, and the width of the connectors.

4. The design method of a constant load clamping device for the injection head of a coiled tubing drilling rig according to claim 1, characterized in that, The steps for iteratively solving the differential-algebraic equation include: Choose the step size and integration order; Identify the nonlinear system of equations; The solution is obtained iteratively using the backward difference method. Determine whether the iteration precision meets the preset value; If the iteration accuracy meets the preset value, then determine whether the integration accuracy meets the preset value. If the iteration precision does not meet the preset value, then determine whether the maximum number of iterations has been reached; If the maximum number of iterations is reached, the step size is reduced and the selection of step size and integration order is returned. If the maximum number of iterations is not reached, the backward difference method is used to solve the problem iteratively. If the integration accuracy meets the preset value, proceed to the next time step; if the integration accuracy does not meet the preset value, reduce the step size and return to select the step size and integration order.

5. The design method of a constant load clamping device for the injection head of a coiled tubing drilling rig according to claim 3, characterized in that, The objective function for the design parameters is as follows: in, , and These represent the weights of average working load, working interval length, and sheet parameters, respectively. , and These represent the average working load, working interval length, and sheet width, respectively. , sheet thickness Installation distance Functions of relations; , and These are the target values ​​for average working load, working interval length, and maximum normal stress of the sheet, respectively.

6. The design method of a constant load clamping device for the injection head of a coiled tubing drilling rig according to claim 1, characterized in that, The clamping device is installed in a double-layer parallel configuration.

7. The design method of a constant load clamping device for the injection head of a coiled tubing drilling rig according to claim 1, characterized in that, The first connector and the second connector are arranged in parallel, and multiple sets of the sheet-cable structures are installed in parallel between the first connector and the second connector, with the sheet-cable structures being perpendicular to the first connector and the second connector respectively.

8. The design method of a constant load clamping device for the injection head of a coiled tubing drilling rig according to claim 1, characterized in that, The first and second sheets are initially in a buckled state, and the cable is only subjected to tensile stress.

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