A heavy-load light-weight coiled tubing injector head clamping block

Abstract

The application discloses a heavy-load light-weight coiled tubing injector head clamping block and belongs to the field of coiled tubing injector heads. The clamping block comprises a clamping seat, a clamping piece, a plunger, a drop-proof screw and an oil injection plug. The clamping seat is internally formed with an annular clamping space for accommodating the coiled tubing and is provided with an M-shaped groove for placing the clamping piece. The clamping piece can move in the radial direction in the M-shaped groove. The clamping seat is provided with a sealed and equal-pressure communication cavity connected with a plunger hole. The plungers uniformly distributed in the circumferential direction and the axial direction of the coiled tubing will be subjected to the same hydraulic pressure of the sealed and equal-pressure communication cavity and will jointly act on the clamping piece in the radial direction and in the axial direction of the coiled tubing. The clamping structure of the application can uniformly distribute the clamping load on the whole clamping surface, can realize greater clamping load on the limited clamping block area, can provide guarantee for the light-weight design of the injector head and can provide technical support for the development of the million-meter coiled tubing operation equipment.

Description

Technical Field

[0001] This invention belongs to the field of coiled tubing injection heads, specifically a heavy-duty lightweight coiled tubing injection head clamping block. Background Technology

[0002] Coiled tubing equipment has been widely used in oil and gas well drilling, workover, and production enhancement operations. As one of the most critical components of a coiled tubing system, the injection head undertakes important functions such as hoisting and running the coiled tubing and applying drilling pressure. Its load-bearing capacity directly determines the safety and applicable well depth range of coiled tubing operations.

[0003] To meet the lifting force requirements of the injection head, existing technologies typically employ two methods: one is to increase the clamping force exerted by a single clamping block on the coiled tubing, and the other is to increase the number or length of clamping blocks in the injection head. However, with the continuous increase in the number of deep and ultra-deep wells, the length of coiled tubing used for various downhole operations continues to grow, gradually approaching the tens of thousands of meters level, significantly increasing the load that the injection head needs to bear. If the load-bearing capacity is increased solely by increasing the structural size or number, it will inevitably lead to an excessively large overall mass of the injection head, not only increasing the difficulty of on-site installation, operation, and transportation, but also contradicting the trend of lightweight development of coiled tubing operation equipment. At the same time, simply increasing the clamping load may also cause excessive local stress on the coiled tubing, posing a risk of the coiled tubing being crushed or destroyed.

[0004] Further analysis of the structural characteristics of existing coiled tubing clamping blocks reveals that, due to the uneven force distribution between the clamping block and the coiled tubing in the circumferential direction, the compressive force between them tends to concentrate within a small arc segment on both sides of the loading line, making it difficult to effectively "distribute" the clamping load in the circumferential direction. This uneven circumferential load clamping method significantly limits the effective load-bearing capacity of the clamping block. When the clamping load is large, it can easily cause local damage or even crushing of the coiled tubing; while when the clamping load is small, the coiled tubing injection head cannot obtain sufficient axial load-bearing capacity, making it difficult to meet the comprehensive requirements of lightweight and high load-bearing capacity for injection heads under the conditions of 10,000-meter-level coiled tubing operations.

[0005] Therefore, the industry urgently needs a new type of coiled tubing injection head clamping block structure that can achieve uniform distribution of clamping load in the circumferential and axial directions without increasing the size and number of clamping blocks. This allows the total clamping load to be effectively "distributed" across the entire clamping surface, enabling the clamping blocks to achieve near "uniform load clamping" within a limited contact area. This significantly improves the total clamping load capacity per unit contact area, providing effective assurance for the heavy-duty and lightweight design of injection heads in equipment for operating 10,000-meter coiled tubing. Summary of the Invention

[0006] The purpose of this invention is to address the technical problems of uneven clamping force distribution and excessive local load on the clamping block under limited space conditions, which can easily damage the coiled tubing, in existing injection head clamping blocks. This invention provides a heavy-duty, lightweight coiled tubing injection head clamping block. By constructing a closed hydraulic force transmission structure inside the clamping block, the clamping load can be evenly distributed in the circumferential and axial directions of the coiled tubing, thereby significantly improving the overall load-bearing capacity of the clamping block under limited structural dimensions. It effectively avoids relative slippage between the clamping block and the coiled tubing, significantly improving the reliability and stability of coiled tubing clamping operations, and providing the most direct support for the heavy-duty, lightweight design of coiled tubing injection heads.

[0007] The objective of this invention is achieved through the following technical solution: a heavy-duty lightweight coiled tubing injection head clamping block, comprising a clamping seat, clamping plates, a plunger, an anti-drop screw, and an injection plug, characterized in that: the clamping seat has an annular clamping space inside for accommodating the coiled tubing, and the annular clamping space has an M-shaped groove circumferentially provided to fit the clamping plates. The clamping plates are respectively embedded in the grooves on both sides of the M-shaped groove, and the groove wall structure guides and limits the clamping plates, so that the clamping plates always move stably in a predetermined direction during the force process, thereby effectively avoiding the off-center load phenomenon and ensuring that the clamping plates can only move 1-5mm in the radial direction of the annular clamping space.

[0008] Multiple plunger holes are formed in the circumferential and axial directions of the annular clamping space within the clamping seat. These plunger holes are evenly distributed on both sides of the M-shaped groove. The circumferential and axial arrangement of the plunger holes ensures a uniform spatial distribution of clamping force, thereby reducing localized stress concentration. Each end of the M-shaped groove has 3-6 plunger holes, evenly distributed circumferentially. The plunger holes are arranged in 4-8 layers along the axial direction of the coiled tubing, forming a multi-layered plunger layout. The axes of each layer of plunger holes intersect at the same point, and these intersection points form a straight line along the axial direction of the coiled tubing. This straight line coincides with the geometric center axis of the coiled tubing, thus improving overall clamping stability.

[0009] The clamping seat has a sealed connecting cavity inside, which includes a radial flow channel and an axial flow channel. The radial flow channel and the axial flow channel are interconnected, so that each plunger is always under pressure with a consistent load, effectively avoiding the problem of uneven clamping load caused by unilateral force.

[0010] The radial flow channel includes a circumferential flow channel and a transverse flow channel arranged circumferentially along the annular clamping space, and the axial flow channel includes a first axial flow channel and a second axial flow channel. The circumferential flow channel is arranged in multiple layers in the axial direction of the clamping seat, and the number of layers is consistent with the number of plunger holes in the axial direction. Each layer of circumferential flow channel is divided into a left circumferential flow channel and a right circumferential flow channel. The left circumferential flow channel is used to connect the plunger holes of the corresponding layer on the left side of the clamping seat, and the right circumferential flow channel is used to connect the plunger holes of the corresponding layer on the right side of the clamping seat. The first axial flow channel is located on the right side of the clamping seat and is used to connect the right circumferential flow channels of each layer. The second axial flow channel is located on the left side of the clamping seat and is used to connect the left circumferential flow channels of each layer. The transverse flow channel is opened at the middle plunger hole position of the clamping seat along the axial direction of the continuous tubing, perpendicular to the axial direction, and is used to connect the first axial flow channel and the second axial flow channel.

[0011] The clamping plates are arc-shaped components, with two in total, installed in the slots on both sides of the M-shaped groove. The inner side of the clamping plate has an arc-shaped structure adapted to the outer wall of the coiled tubing to increase the contact area with the coiled tubing and improve the total clamping load. The clamping plates are connected to the clamping seat via anti-drop screws. The anti-drop screws pass through the through holes on the clamping seat and connect to the first and second threaded blind holes on the clamping plate. The anti-drop screws also engage with the groove wall of the M-shaped groove, allowing the clamping plates to be reliably positioned while permitting limited radial displacement. After radial displacement, there is no direct rigid force transmission between the clamping seat and the clamping plates in the radial direction; instead, hydraulic pressure is transmitted through the plunger.

[0012] The plunger is a cylinder that slides into the plunger hole of the clamping seat, with one end of the plunger contacting the clamping plate and the other end connected to the communicating cavity. A ring groove is formed around the outer wall of the plunger, and a sealing ring is embedded in the ring groove to form a sealing structure, thereby ensuring that the sealed communicating cavity does not leak liquid under high load.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. Uniformly Distributed Clamping Load: By constructing a sealed, interconnected cavity and utilizing the isobaric transmission characteristics of the hydraulic medium, each plunger generates a radial clamping force of the same magnitude. The plungers, evenly distributed circumferentially and axially, then apply equal radial clamping forces to the clamping plates, achieving a uniform distribution of clamping force on the coiled tubing. This design can achieve a larger total clamping load within a limited clamping contact area, meeting heavy-duty operation requirements without increasing the number of clamping blocks, and significantly improving the load-bearing capacity of the coiled tubing injection head.

[0015] 2. Lightweight design with wide adaptability: Through the optimization of the hydraulic load-sharing structure, the overall weight of the injection head is effectively reduced without increasing the volume or number of clamping blocks, while ensuring heavy-duty clamping capacity. This provides key technical support for the lightweight upgrade of continuous tubing injection heads and broadens the new path for lightweight design of injection heads.

[0016] 3. Protects the tubing and extends its service life. Compared with the problem of localized stress concentration that is prone to occur in traditional clamping methods, the uniform load design of this invention can avoid damage such as plastic deformation and surface scratches caused by local extrusion of the continuous tubing, significantly extending the service life of the continuous tubing and reducing the cost and safety risks of tubing replacement during operation. Attached Figure Description

[0017] Figure 1 This is a front view of the clamping seat.

[0018] Figure 2 This is a 3D diagram of the clamping seat.

[0019] Figure 3 for Figure 1 Sectional view of section AA.

[0020] Figure 4 for Figure 1 BB section with plunger cross-section.

[0021] Figure 5 for Figure 1 Cross-sectional view of section AA with plunger.

[0022] Figure 6 for Figure 4 II. Rotational section view.

[0023] Figure 7 for Figure 5 CC section cross-section view.

[0024] Figure 8 for Figure 5 DD cross-sectional view.

[0025] Figure 9 for Figure 5 EE cross-sectional view.

[0026] Figure 10 for Figure 5 GG cross-sectional view.

[0027] Figure 11 for Figure 9 FF cross-sectional view.

[0028] Figure 12 for Figure 10HH initial position cross-section after installing anti-drop screws and clamping plates.

[0029] Figure 13 for Figure 10 Cross-sectional view of the HH device under clamping force after the anti-drop screws and clamping plates are installed.

[0030] Figure 14 This is a 3D view of the clamping plate.

[0031] Figure 15 This is a cross-sectional view of the clamping block assembly.

[0032] In the diagram: 1. Clamping seat; 2. Clamping plate; 3. Plunger; 4. Anti-drop screw; 5. Oil filling plug; 6. Continuous oil tubing; 1-1. Plunger hole; 1-2. Circumferential flow channel; 1-3. Transverse flow channel; 1-4. First axial flow channel; 1-5. Second axial flow channel; 1-6. Oil filling hole; 1-7. Vent hole; 1-8. First through hole; 1-9. Second through hole; 1-10. Third through hole; 1-11. Fourth through hole; 1-12. "M" groove; 2-1. First threaded blind hole; 2-2. Second threaded blind hole. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that the directional terms "upper," "lower," "left," and "right" used in this invention are all based on the appendix. Figure 1 The front view shown is defined based on a reference perspective and is intended to clearly describe the structural relationships of the technical solutions. It does not constitute a limitation on the scope of protection of this invention. The terms "first," "second," "third," and "fourth" are used for descriptive purposes only and do not imply relative importance.

[0035] like Figures 1 to 13 As shown, the heavy-duty lightweight continuous tubing injection head clamping block of the present invention includes a clamping seat 1, a clamping plate 2, a plunger 3, an anti-drop screw 4, and an injection plug 5. The clamping seat 1 is an integrated rectangular column structure, made of high-strength material, which takes into account both structural strength and lightweight requirements. Its key structural design is as follows:

[0036] Guide and limiting structure: A rounded M-shaped groove 1-12 is provided on the inner side of the clamping base 1. The central axes of the arc segments on both sides of the M-shaped groove 1-12 are inclined to the left at 45° and to the right at 45° respectively, and the included angle between the two central axes is 90°. The groove wall precision of the M-shaped groove 1-12 is controlled at IT8 level. As the guide and limiting reference of the clamping piece 2, it can strictly constrain the movement trajectory of the clamping piece 2, ensuring that it only produces controlled displacement in the radial direction, avoiding radial wobble or jamming, and ensuring the smoothness of the clamping action.

[0037] Limiting through holes: The upper and lower ends of the outer diagonal position of the clamping base 1 are respectively provided with a first through hole 1-8, a second through hole 1-9, a third through hole 1-10 and a fourth through hole 1-11. All of the above through holes are through holes with steps. The gap between the step surface and the end face of the anti-drop screw 4 is reserved at 1-5mm for assembling the anti-drop screw 4, so as to realize the axial limitation of the clamping piece 2, and at the same time reserve space for its radial movement.

[0038] Plunger hole layout: The clamping seat 1 forms an annular clamping space for accommodating the coiled tubing 6. Plunger holes 1-1 are formed along the circumference and axial direction of this annular clamping space. The circumferential distribution of the plunger holes 1-1 is as follows: the plunger holes 1-1 are evenly distributed along the arc segment of the M-shaped groove 1-12. The number of plunger holes 1-1 at the left and right arc ends of the M-shaped groove 1-12 is 3-6 each, preferably 3 in this embodiment, to ensure uniform distribution of circumferential clamping force. The axial distribution of the plunger holes 1-1 is as follows: along the axial direction of the coiled tubing 6, the plunger holes 1-1 are arranged in 4-8 layers, preferably 5 layers in this embodiment, forming a multi-layer plunger layout. The spatial positioning of the plunger holes 1-1 is as follows: the axes of each layer of plunger holes 1-1 intersect at the same intersection point. The intersection points of each layer are arranged along the axial direction of the coiled tubing 6 to form a straight line, and this straight line coincides with the geometric center axis of the coiled tubing 6. With this symmetrical layout, there are 3 plungers on each side, totaling 5 layers, so that the 30 plungers can apply equal force to the clamping plate 2. The clamping load is distributed symmetrically along the spatial axis, which avoids the problems of off-center loading and stress concentration in traditional clamping devices from the structural design perspective.

[0039] Sealed Connecting Cavity: The clamping seat 1 has an integrated flow channel structure inside, forming a closed-loop connected hydraulic cavity, specifically including circumferential flow channels 1-2: divided into a left circumferential flow channel and a right circumferential flow channel, opened along the circumference of the annular clamping space, with 5 layers corresponding to the number of plunger holes 1-1 in the axial direction. The flow channel diameter is preferably φ3mm. The left circumferential flow channel of each layer connects to the 3 plunger holes 1-1 on the left side of that layer, and the right circumferential flow channel connects to the 3 plunger holes 1-1 on the right side of that layer; Axial flow channels: including a first axial flow channel 1-4 and a second axial flow channel 1-5, located on the left and right sides of the clamping seat 1 respectively, with the flow channel diameter preferably φ5mm. Both axial flow channels axially penetrate the 5 plunger holes 1-1 on their respective sides. Circumferential flow channel; Transverse flow channel 1-3: opened at the position of the third layer of plunger holes in the middle of the axial direction, perpendicular to the axial direction, the flow channel is preferably φ7mm in diameter, and the two ends are connected to the first axial flow channel 1-4 and the second axial flow channel 1-5 respectively, forming a closed connected cavity, ensuring that the force applied to the clamping plate by each plunger 3 is consistent during the clamping process. At any moment, when the force is concentrated or the load is uneven at any position, because the pressure in the internal connected cavity is always consistent, it will automatically adjust in a very short time to make the force of all plungers become consistent, thereby avoiding the phenomenon of uneven local force on the coiled tubing. This isobaric transmission structure significantly improves the uniformity of the clamping load between the clamping plate and the coiled tubing.

[0040] The oil injection hole 1-6 is located at the upper end of the second axial flow channel 1-5 and is used to inject hydraulic oil, preferably anti-wear hydraulic oil, such as L-HM46 hydraulic oil. The injection pressure is controlled at 0.05-1MPa, preferably 0.1-0.3MPa. The vent hole 1-7 is located at the upper end of the first axial flow channel 1-4 and is used to expel air from the cavity during oil injection. This prevents excessive radial displacement of the clamping plate due to gas compression, which would prevent the clamping force from being effectively transmitted through the plunger and instead be transmitted directly through the rigid force between the clamping seat and the clamping plate, thus causing uneven clamping force. The sealing design is as follows: Figure 3 As shown, weld plug structures are used at the ends of the circumferential flow channels 1-2 and the transverse flow channels 1-3 that connect to the outside, preferably filled with solder or formed by fusion welding; after oil injection, as shown... Figure 6 As shown, the oil filling hole 1-6 and the vent hole 1-7 are sealed by the oil filling plug 5 connected by threads to ensure the airtightness of the connected cavity.

[0041] The clamping plate 2 is an arc-shaped component, with two clamping plates on each clamping seat. The inner arc-shaped surface of the clamping plate has a suitable surface roughness, which can generate a stable frictional clamping effect on the coiled tubing without damaging its outer surface. Each clamping plate 2 has a first threaded blind hole 2-1 and a second threaded blind hole 2-2 at its upper and lower ends, respectively. The thread specification matches the anti-drop screw 4, ensuring that the clamping plate 2 can still generate a radial displacement of 1-5mm after the anti-drop screw 4 is assembled. The actual displacement depends on the clamping force and the compressibility of the oil. Figure 12 and Figure 13 The figures show the clamping piece in its stationary state and in its moved state, respectively.

[0042] The plungers 3 are cylindrical, with a total of 30 plungers. The outer diameter tolerance is controlled at grade f7, and they are clearance-fitted with the plunger holes 1-1. A ring groove is formed around the outer wall of each plunger 3, and a sealing ring is embedded therein to form a sealing structure with the communicating cavity, preventing high-pressure oil leakage due to high load on the clamping seat.

[0043] The anti-drop screw 4 is an internal hexagonal cylindrical head anti-drop screw, with a total of 4 screws, 2 on each clamping piece, one on the top and one on the bottom. It is threaded into the through hole of the clamping base 1. A clearance is reserved between the screw head and the stepped surface of the through hole to accommodate the radial displacement of the clamping piece during the clamping process.

[0044] A method for installing a heavy-duty, lightweight coiled tubing injection head clamping block, such as... Figures 1 to 13 As shown, it includes the following steps:

[0045] S1: Plug-in: After machining the circumferential flow channels 1-2 and transverse flow channels 1-3 on the clamping seat 1, as shown in the image... Figure 3 As shown, the end of the borehole is sealed by plugging welding, preferably by filling with solder or fusion welding, so that the end of the flow channel forms a permanent sealing structure, which structurally prevents hydraulic medium leakage and improves the overall pressure resistance.

[0046] S2: Plunger assembly: Install sealing rings into the annular grooves of 30 plungers 3 respectively, and then slide the plungers 3 one by one into the plunger holes 1-1 of the clamping seat 1 to ensure that the plungers 3 can slide smoothly along the plunger holes 1-1 and that the sealing rings are tightly fitted to the inner wall of the plunger holes 1-1 without loosening.

[0047] S3: Take the first clamping piece 2 and align its first threaded blind hole 2-1 with the axis of the first through hole 1-8 at the upper end of the clamping seat 1, and align its second threaded blind hole 2-2 with the axis of the second through hole 1-9 at the lower end of the clamping seat 1. Limit the first clamping piece 2 with two anti-drop screws 4. Using the same method, fix the second clamping piece 2 to the third through hole 1-10 and the fourth through hole 1-11 of the clamping seat 1 with another two anti-drop screws 4. At this time, the two clamping pieces 2 are located on the left and right sides of the M-shaped groove 1-12 respectively, and the inner arc structure forms an annular space that is compatible with the continuous tubing 5.

[0048] S4: Oil injection and sealing: Hydraulic oil is injected into the internal communicating cavity through the oil injection hole 1-6 provided on the clamping seat 1. The hydraulic oil flows sequentially through the transverse flow channel 1-3, the first axial flow channel 1-4, the second axial flow channel 1-5, and each layer of circumferential flow channel 1-2. During the oil injection process, the vent hole provided at the top of the first axial flow channel gradually discharges the air in the cavity to ensure that there is no gas residue in the hydraulic cavity. After the hydraulic oil fills each flow channel and overflows steadily from the vent hole, the oil injection hole is sealed by the oil injection plug 5 threaded to the oil injection hole 1-6. At the same time, the vent hole is also sealed, thereby forming a closed hydraulic cavity inside the clamping seat 1. A one-way valve structure can be installed inside the oil filling plug 5 of the oil filling hole, so that the hydraulic oil can only enter the connecting cavity in one direction and cannot flow back, thereby establishing a working pressure of 0.1 to 1 MPa, preferably 0.1 to 0.3 MPa, in the sealed connecting cavity. Under this pressure, the plunger 3 pushes the clamping plate 2 to move radially inward. At the same time, because the anti-drop screw 4 and the stepped structure of the through hole on the clamping seat form a limit, the clamping plate can only produce a small displacement in the radial direction. Figure 13 As shown.

[0049] S5: Installing the clamping blocks: The clamping blocks are installed on the chain drive assembly of the injection head, with multiple clamping blocks spaced apart circumferentially along the chain. The chain circulates under the drive of the drive device. When a clamping block enters the clamping area, the external hydraulic system applies a force to the clamping seat, pressurizing the hydraulic oil in the sealed communicating cavity inside the clamping seat. The pressurized hydraulic oil generates a reaction force on the plunger, and the clamping force is transmitted to the clamping plate through the plunger. Since all the plungers apply equal forces to the clamping plate, and the direction of the forces is always towards the axis of the continuous tubing, the clamping plate can apply a uniform axial and circumferential clamping force to the continuous tubing.

[0050] The working principle of this invention is as follows: The clamping force is not directly transmitted through rigid contact between the clamping seat and the clamping plate, as in traditional clamping blocks. Instead, it is based on the principle of hydraulic isobaric transmission, achieving clamping of the coiled tubing by constructing a closed, interconnected hydraulic cavity. When hydraulic oil is injected into the clamping seat through the injection port, a consistent oil pressure is formed in the closed channel formed by the circumferential, transverse, and axial flow channels. During clamping, driven by external loads, the fluid inside the clamping seat is under pressure. Due to the slight compressibility of the hydraulic medium, the clamping block is designed with a certain radial movement space to accommodate the slight compression of the oil, ensuring that each plunger experiences a uniform radial force. The direction of all plunger forces points towards the axis of the coiled tubing. Because the plungers are arranged in a "distributed" manner in the axial and circumferential directions, the clamping load is evenly distributed along the axial and circumferential directions of the coiled tubing, avoiding localized deformation, slippage, or damage to the coiled tubing caused by concentrated force in traditional rigid clamping structures. By constructing a closed and interconnected hydraulic cavity and multi-layered plungers, the total clamping load per unit clamping area is significantly increased. Under a certain axial load on the injection head, the total number of clamping blocks required can be effectively reduced, the total height of the injection head can be reduced, and a lightweight design of the injection head can be achieved.

[0051] Through the combined effect of the above structure and hydraulic load-sharing mechanism, this invention can ensure sufficient clamping force without increasing the volume or number of clamping blocks, thus broadening the new path for lightweight design of the injection head. At the same time, it can achieve load-sharing clamping of the continuous tubing, with a larger total clamping load within a limited clamping contact area, avoiding the risk of deformation or crushing of the continuous tubing due to localized force concentration.

[0052] Finally, it should be noted that 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heavy-duty, lightweight coiled tubing injection head clamping block, characterized in that, It includes a clamping seat (1), a clamping plate (2), a plunger (3), an anti-drop screw (4), and an oil filling plug (5). The clamping seat (1) forms an annular clamping space for accommodating a continuous oil pipe (6), and an M-shaped groove (1-12) is provided in the circumference of the annular clamping space. The clamping plates (2) are respectively embedded in the slots on both sides; the clamping seat (1) has multiple plunger holes (1-1) along the circumferential and axial directions of the clamping space, and the plungers (3) are respectively installed in the corresponding plunger holes; the clamping seat (1) has interconnected circumferential flow channels (1-2), axial flow channels and transverse flow channels (1-3), and each plunger hole is connected to the flow channels; the anti-drop screw (4) passes through the stepped through hole opened on the clamping seat (1) and connects with the threaded hole opened on the clamping plate (2) to install the clamping plate (2) in the M-shaped groove (1-12); the clamping seat (1) has an oil injection hole (1-6) and an exhaust hole (1-7) connected to the flow channels, and the oil injection plug (5) is sealed and installed at the oil injection hole (1-6) and the exhaust hole (1-7).

2. The heavy-duty lightweight coiled tubing injection head clamping block as described in claim 1, characterized in that, The plunger holes (1-1) are evenly distributed along the circumferential direction of the clamping space and symmetrically arranged on both sides of the circumferential direction of the M-shaped groove (1-12). The number of plunger holes (1-1) at both ends of the circumferential direction of the M-shaped groove (1-12) is 3-6. The number of plunger holes (1-1) on the clamping seat (1) along the axial direction of the coiled tubing (6) is 4-8. The axes of each layer of plunger holes (1-1) intersect at the same intersection point. The intersection points of the axes of each layer of plunger holes (1-1) are arranged along the axial direction of the coiled tubing to form a straight line, and the straight line coincides with the geometric center axis of the coiled tubing (6).

3. The heavy-duty lightweight coiled tubing injection head clamping block as described in claim 1, characterized in that, The circumferential flow channel (1-2) is provided in multiple layers in the axial direction of the clamping seat. Each layer of the circumferential flow channel is divided into a left circumferential flow channel and a right circumferential flow channel. The number of layers is the same as the number of plunger holes in the clamping seat in the axial direction. The left circumferential flow channel connects to the plunger hole on the left side of the layer, and the right circumferential flow channel connects to the plunger hole on the right side of the layer. The axial flow channel includes a first axial flow channel (1-4) and a second axial flow channel (1-5) provided on both sides of the clamping seat (1). The first axial flow channel (1-4) connects to the right circumferential flow channel of each layer, and the second axial flow channel (1-5) connects to the left circumferential flow channel of each layer. The transverse flow channel (1-3) connects the first axial flow channel (1-4) and the second axial flow channel (1-5).

4. A heavy-duty, lightweight coiled tubing injection head clamping block as described in claim 1 or 3, characterized in that, The circumferential flow channel (1-2) and the transverse flow channel (1-3) are sealed to the outside by plug welding; an exhaust hole is opened at the top of the first axial flow channel and an oil injection hole is opened at the top of the second axial flow channel. The clamping seat (1) is connected to the outside only through the plunger hole (1-1), the oil injection hole (1-6) and the exhaust hole (1-7). The oil injection hole (1-6) and the exhaust hole (1-7) are sealed by the threaded oil injection plug (5); a sealing structure is provided between the plunger (3) and the plunger hole (1-1) to form a closed connected cavity.

5. The heavy-duty lightweight coiled tubing injection head clamping block as described in claim 1, characterized in that, The clamping seat (1) has a stepped through hole at the upper end of the coiled tubing, offset from the plunger hole (1-1). The through holes are diagonally distributed in the circumferential direction of the clamping seat (1), namely the first through hole (1-8) and the third through hole (1-10). The clamping seat (1) has a stepped through hole at the lower end of the coiled tubing, offset from the plunger hole (1-1). The through holes are diagonally distributed in the circumferential direction of the clamping seat (1), namely the second through hole (1-9) and the fourth through hole (1-11). A movable gap is reserved between the anti-drop screw (4) and the step of the through hole, so that the clamping piece (2) has a movable stroke of 1-5mm in the radial direction.

6. The heavy-duty lightweight coiled tubing injection head clamping block as described in claim 1, characterized in that, The flow channel inside the clamping seat (1) is filled with a liquid medium. After the liquid medium is filled with the connecting cavity, there is no gas present. The internal pressure range is 0.05-1MPa.

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