Composite wellhead switching-free dredging and scraping tool and method

Abstract

The invention belongs to the technical field of oil production engineering, and discloses a composite wellhead switching-free dredging and scraping tool and method.The center pipe of the tool is in threaded connection with an upper connector, the upper connector is in threaded connection with a barrel, an expansion block is embedded into the barrel and movably connected with the barrel, and the expansion block is sleeved with a hoop spring; the central pipe positioning sleeve is mounted on the cylinder body in an interference fit, key connection or threaded connection manner, the circular bridge is movably connected with the central pipe positioning sleeve in a threaded or clamping groove manner, and the safety pin penetrates through a pin hole in the circular bridge. The problems of a traditional operation mode are effectively solved, safety and reliability are achieved, the expansion block is ensured to be in place through insertion connection of the center pipe, the drifting effect is guaranteed, the unverifiability of rotary expansion and pressing expansion is eradicated, and the well control risk and the safety operation risk are reduced. The construction efficiency is improved, the tedious operation of repeatedly switching the wellhead is avoided, and the construction period is shortened.

Description

Technical Field

[0001] This invention relates to the field of oil production engineering technology in petroleum extraction, and to related tools and operating techniques for deep well composite wellheads, specifically a composite wellhead non-replacing cleaning and scraping tool and method. Background Technology

[0002] In the extraction of oil and gas resources such as petroleum and natural gas, wellhead operations are a crucial link in ensuring the normal production and maintenance of oil and gas wells. Among them, well cleaning and well wall scraping operations, as important components of wellhead operations, play a vital role in ensuring unobstructed wellbore access, maintaining wellbore integrity, and improving oil and gas extraction efficiency.

[0003] The main purpose of well cleaning operations is to check the wellbore's patency, remove any debris, sand, or other obstructions, and ensure the smooth progress of subsequent operations. Traditional well cleaning tools typically have a simple structure and relatively limited functionality. They generally employ a rod-shaped or tubular structure with sufficient strength, relying on their own weight or the impact force during lowering to remove debris from the well.

[0004] However, in actual operations, the well conditions vary greatly across different well sections. For example, some sections may contain hard debris, while others may have thick layers of sand. Traditional well cleaning tools are difficult to adjust flexibly to suit different well conditions. When encountering hard debris, they may not be able to effectively remove it due to insufficient impact force. When dealing with sand layers, unreasonable tool structures may lead to incomplete sand removal or even sand jamming accidents, seriously affecting the efficiency and safety of well cleaning operations.

[0005] Furthermore, traditional well cleaning operations often require multiple tripping of drill strings to change to different specifications or functions of cleaning tools to adapt to varying well conditions. This not only increases operation time and costs but also intensifies the workload for workers and increases the probability of complex downhole situations such as wellbore collapse and drill string breakage.

[0006] When performing large-diameter wellbore cleaning and scraping operations with 9-inch 5-casing casing at the deep wellhead, traditional methods require repeated wellhead switching. This process presents several problems: First, it poses well control risks, as frequent wellhead switching can easily lead to pressure imbalances within the well, potentially causing safety accidents. Second, it poses operational safety risks, increasing the workload and complexity of operations for personnel and increasing the likelihood of misoperation. Third, it impacts construction efficiency, as wellhead switching consumes a significant amount of time, extending the construction cycle. Currently, the main method for this process is repeated wellhead switching. While this method accomplishes the task, it lacks effective optimization of tool structure and operational procedures, and the aforementioned risks and efficiency issues persist.

[0007] CN209083249U discloses a split-type self-sealing wellhead sealer for tubing. During downhole operations, when running and pulling tubing, it can scrape oil sludge from the outer wall of the downhole tubing into the well, facilitating the replacement and installation of the self-sealing wellhead sealer. This tubing self-sealing wellhead sealer includes an upper fixed body, a lower fixed body, and a self-sealing core. Both the upper and lower fixed bodies are split, connected by an upper fixing pin and a lower fixing pin, respectively. The self-sealing core is clamped between the upper and lower fixed bodies and fixed by connecting bolts. Using this device avoids the safety hazard of workers lifting the self-sealing core high when the tubing rotates, ensuring construction safety. However, this technical solution lacks a comprehensive technical solution and innovative design for improving safety and efficiency in deep well composite wellhead operations, particularly for well cleaning and scraping processes that eliminate the need for replacement. Summary of the Invention

[0008] This invention aims to develop a novel tool and operating method to avoid the need for repeated wellhead switching during the large-diameter wellbore cleaning or scraping process using 9-inch 5-casing casing in deep wells, thereby reducing well control and safety risks and improving construction efficiency. This application specifically addresses the large-diameter wellbore cleaning process using 9-inch 5-casing casing, where a wellhead switching is required to lower the casing to a larger diameter; smaller casings can be lowered directly without switching.

[0009] To solve the above-mentioned technical problems, a composite wellhead cleaning and scraping tool without the need for casing swapping has been developed, changing the existing methods of running in and out of large casing for well cleaning and scraping. The specific technical solution is as follows: A composite wellhead non-replacing scraping tool is provided, wherein the central tube is threadedly connected to the upper connector, the upper connector is threadedly connected to the cylinder, the expansion block is embedded inside the cylinder and movably connected to the cylinder, the clamp spring is sleeved on the outside of the expansion block, the central tube positioning sleeve is installed on the cylinder by interference fit, key connection or threaded connection, the circular bridge is connected to the central tube positioning sleeve by threaded joint or groove, and the safety pin passes through the pin hole on the circular bridge.

[0010] Furthermore, the tool also includes a scraper blade, which is connected to the expansion block by screws.

[0011] Furthermore, the expansion block is embedded in the inner hole opened on the cylinder and is movably connected to the cylinder.

[0012] Furthermore, the central tube is a cylindrical oil pipe with threads at both ends.

[0013] Furthermore, the expanded blocks are irregularly shaped.

[0014] Furthermore, the center tube positioning sleeve has internal threads.

[0015] A composite wellhead bypass scraping method involves using tubing to expand the expansion block to the wellhead clearance condition. At this point, the central tube is inserted, and the expansion block expands further. When the tubing string is pulled out after the construction is completed, the tubing is unloaded according to the normal procedure. When the tubing is visible, the central tube is pulled out first, and the expansion block can be retracted to a free state, avoiding the tool getting stuck at the wellhead.

[0016] Furthermore, the oil pipe is a 2.5-inch oil pipe.

[0017] Furthermore, before the wellbore is opened, the expansion block is expanded using tubing, and a 3-inch tubing connection tool is used.

[0018] Furthermore, the scraper blade is made of film.

[0019] Compared with the prior art, the beneficial effects of the present invention include: The composite wellhead cleaning tool and method provided by this invention effectively solves the problems of traditional operation methods. It is safe and reliable; the central tube insertion connection ensures the expansion block is in place, guaranteeing well cleaning results and eliminating the unverifiable nature of rotational expansion and pressure expansion, reducing well control risks and operational safety risks. It avoids misoperation; when pulling out the tubing string, it pulls out the tubing in sequence, and after the central tube is pulled out, the expansion block can be retracted to a free state, preventing the tool from getting stuck at the wellhead due to incorrect tubing string calculations. It can be reduced in size when stuck; if stuck during well cleaning, the expansion block can be retracted by pulling out the central tube (the central tube connection threaded seat has a safety pin), facilitating the handling of complex situations such as tubing jamming and improving construction safety and reliability. The length can be arbitrarily increased according to the length of the subsequent construction tools. It improves construction efficiency, avoids the tedious operation of repeatedly switching wellheads, and shortens the construction cycle. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the tool's initial state; Figure 2 yes Figure 1 A sectional view; Figure 3 This is a schematic diagram of the tool's expansion state; Figure 4 This is a diagram illustrating the tool's transformation into a scraper. Figure 5 This is a schematic diagram of the tool's structure.

[0021] The components are: 1. central tube, 2. upper connector, 3. cylinder, 4. expansion block, 5. clamp spring, 6. central tube positioning sleeve, 7. circular bridge, 8. safety pin, 9. scraper, and 10. screw. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] Example 1 A composite wellhead cleaning tool that eliminates the need for manual replacement includes a central tube 1, an upper connector 2, a cylindrical body 3, an expansion block 4, a clamping spring 5, a central tube positioning sleeve 6, a circular bridge connector 7, and a safety pin 8. Wherein: The central tube 1 and the upper connector 2 are connected by threads to ensure that the central tube 1 and the upper connector 2 are tightly fixed, which facilitates the transmission of force and the overall assembly.

[0024] Upper connector 2 and cylinder 3: The upper connector 2 is connected by a thread, which allows the upper connector 2 to be firmly connected to one end of the cylinder 3, forming the main frame structure of the tool.

[0025] Cylinder 3 and expansion block 4: Expansion block 4 is embedded inside cylinder 3 and is movably connected to cylinder 3. Relying on the constraint and guidance of cylinder 3, expansion block 4 can expand outward to perform corresponding functions when needed.

[0026] Expansion block 4 and hoop spring 5: Hoop spring 5 is sleeved on the outside of expansion block 4. It applies a constraint to expansion block 4 through its own elastic force, so that expansion block 4 remains contracted in the non-working state and can be released and expanded in the working state.

[0027] Cylinder 3 and central tube positioning sleeve 6: The central tube positioning sleeve 6 can be installed on the cylinder 3 by means of interference fit, key connection or threaded connection, etc., to position and fix the central tube 1 and prevent the central tube 1 from moving axially or circumferentially.

[0028] The central tube positioning sleeve 6 and the circular bridge 7: The circular bridge 7 can be connected to the central tube positioning sleeve 6 by means of threads, slots, etc., and plays the role of connecting and transmitting force, coordinating the movement of various components.

[0029] Circular bridge 7 and safety pin 8: The safety pin 8 passes through the pin hole on the circular bridge 7, which plays a role in safety protection and positioning. When a certain load is reached, the safety pin 8 will shear off and break to prevent the component from being damaged by overload.

[0030] The expansion block 4 and the inner hole on the cylinder 3 are embedded and will not fall off.

[0031] In the initial state of the tool, the expansion block 4 is in a free state and is embedded in the cylinder 3. During use, the expansion block 4 is expanded to the well-clearing condition through a specific tubing connection method. At this time, the central tube 1 is inserted, and the expansion block 4 expands outward. When the tubing string is pulled out after the operation is completed, the tubing is unloaded according to the normal procedure. When the 2.5-inch central tube is seen, the central tube 1 is pulled out first, and the expansion block 4 can be retracted to the free state, avoiding the tool getting stuck at the wellhead.

[0032] Figure 1 As the tool's initial state, expansion block 4 is in a free state. Figure 2 It can be seen that the expansion block 4 is clamped inside the cylinder 3. Figure 3 With the central tube 1 inserted and expansion block 4 bulging outwards, the well is in a vented state. During use, first insert the tool into the well in its initial state, typically using 3-inch tubing to connect the tool. After exceeding the four-way connector, lower 2.5-inch tubing to expand the tool to... Figure 3 Once the well is in good condition, run another 3-inch tubing. After inserting the 2.5-inch tubing, run the tubing string according to the condition of the tubing string in the well. When initially running the tubing string, unload the tubing according to the normal procedure. When the 2.5-inch center tube is seen, first pull out the center tube 1, and then proceed with the operation in sequence.

[0033] Among them, three-inch oil pipe and three-inch center pipe refer to oil pipes with an outer diameter of 88.9mm, while two-and-a-half-inch oil pipe and two-and-a-half-inch center pipe refer to oil pipes with an outer diameter of 73mm.

[0034] The central tube 1 is a cylindrical oil pipe with an outer diameter of 73mm and an inner diameter of 62mm. It is made of 35CrMo and has threads at both ends.

[0035] The upper connector 2 is the connection part of the tool itself, which facilitates its lowering into the well and is the fulcrum for the hoisting clamp. Its outer diameter is 107mm.

[0036] The diameter of cylinder 3 is 170mm.

[0037] The expansion block 4 has an irregular shape of 60×180×72mm.

[0038] The center tube positioning sleeve 6 has internal threads and can be connected to the center tube 1 in a forward rotation.

[0039] The circular hinge 7 is a component that connects the central tube positioning sleeve 6 and the cylinder 3 by means of threads.

[0040] When connecting the central tube 1 and the central tube positioning sleeve 6, if you want to remove the expansion block 4 without selecting it, you can pull it up forcefully to cut off the safety pin 8 and then remove it. The safety pin 8 is the connecting component that connects the central tube positioning sleeve 6 and the circular bridge 7.

[0041] Example 2 A scraper blade 9 can be added to the expansion block 4. For example... Figure 4 As shown, by installing a scraper blade 9 on the outside of the expansion block 4, it can be used as a scraper to perform scraping operations. The scraper blade 9 is connected to the expansion block 4 by screws 10.

[0042] 1. Preparations before the assignment Tool Inspection and Assembly: Carefully inspect all components of the scraper for integrity, ensuring that the expansion block 4, scraper blade 9, screws 10, etc., are securely connected without any looseness or damage. Properly connect the scraper to other necessary downhole tools, such as drill pipe, ensuring reliable and airtight connections.

[0043] Well condition assessment: Collect relevant data on the target well, including well diameter, well depth, well wall condition (such as the distribution of mud cake, scale, rust, etc.), and the properties of the fluid inside the well. Select a suitable scraper material (such as a soft and elastic sheet that can adapt to irregular shapes of the well wall, effectively removing debris while minimizing damage) based on the well condition, and determine the scraping operation parameters, such as the lowering speed, rotation speed, and applied pressure.

[0044] Equipment commissioning: Commission and test surface equipment, such as drilling rigs and mud pumps, to ensure their normal operation. Check the mud circulation system to ensure that the mud properties meet the requirements of scraping operations and can promptly carry scraped debris out of the wellhead.

[0045] 2. Lower the scraper The connected scraper is slowly lowered into the well using the drilling rig. During the lowering process, close monitoring of parameters on equipment such as the weight indicator is essential to determine if the scraper encounters resistance or jamming. Simultaneously, the lowering speed of the scraper is controlled according to the well conditions and preset parameters, generally maintaining a slow and uniform descent to allow the scraper blades to gradually contact the wellbore and begin scraping operations.

[0046] 3. Scraping operation Rotary scraping: After the scraper is lowered to the predetermined depth, the drilling rig is started to rotate the scraper. During rotation, the scraper blades rub against the well wall, scraping off mud cake, scale, rust, and other deposits. The rotation speed is adjusted according to the hardness of the well wall and the adhesion of the contaminants. If the well wall is hard or the contaminants are firmly attached, the rotation speed can be increased to enhance the scraping effect; conversely, the rotation speed should be decreased to avoid excessive damage to the well wall.

[0047] Up-and-down reciprocating motion: While rotating, the scraper can also move up and down. The drilling rig controls the scraper's movement within a specific well section, ensuring the scraper blades fully cover the wellbore, guaranteeing uniform and thorough scraping. The amplitude and frequency of the up-and-down reciprocating motion can be adjusted according to well conditions.

[0048] Mud circulation: Turn on the mud pump to circulate the mud within the well. The mud serves two purposes: firstly, it carries scraped debris out of the wellhead, keeping the well clean; secondly, it washes and protects the well wall after scraping, preventing well wall collapse. The mud flow rate and properties are adjusted as needed based on the progress of the scraping operation and the removal of debris from the well.

[0049] 4. Operation monitoring and adjustment During the scraping operation, continuously monitor various parameters, such as pressure changes shown by the weight indicator, slurry return, rotation speed, and lowering speed. If an abnormally high pressure is detected, it may indicate that the scraper is jammed. In this case, stop the operation immediately, analyze the cause, and take appropriate measures, such as adjusting the scraper position or reducing the rotation speed. Judge the effectiveness of the scraping operation based on the slurry return. If the return material still contains a large amount of contaminants, the scraping time can be appropriately extended or the operating parameters adjusted.

[0050] 5. End of work and removal of tools Once the desired scraping effect is achieved, stop the scraper's rotation and reciprocating motion, and slowly lift the scraper up. During the lifting process, closely monitor parameters such as the weight indicator to ensure the scraper is removed smoothly. After removing the scraper from the wellhead, clean and inspect it, removing dirt from the scraper blades and checking for damage or wear on any components for repair or replacement, preparing for the next operation.

[0051] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A composite wellhead without swabbing through scraping tool, characterized in that, The central tube (1) is threaded to the upper connector (2), the upper connector (2) is threaded to the cylinder (3), the expansion block (4) is embedded inside the cylinder (3) and is movably connected to the cylinder (3), the hoop spring (5) is sleeved on the outside of the expansion block (4), the central tube positioning sleeve (6) is installed on the cylinder (3) by interference fit, key connection or threaded connection, the circular bridge (7) is connected to the central tube positioning sleeve (6) by threaded connection or slot, and the safety pin (8) passes through the pin hole on the circular bridge (7).

2. The composite wellhead run-in-the-coil scratcher tool of claim 1, wherein, The tool also includes a scraper (9), which is connected to the expansion block (4) by a screw (10).

3. The composite wellhead run-in-the-coil tool of claim 1 or 2, wherein, The expansion block (4) is embedded in the inner hole of the cylinder (3) and is movably connected to the cylinder (3).

4. The composite wellhead without switching and through scraping tool according to claim 1 or 2, characterized in that, The central tube (1) is a cylindrical oil pipe with threads at both ends.

5. The composite wellhead non-switching scraper tool according to claim 1 or 2, characterized in that, The expansion block (4) is irregular in shape.

6. The composite wellhead run-in-the-coil tool of claims 1 or 2, wherein, The center tube positioning sleeve (6) has internal threads.

7. The composite wellhead run-in-the-coil swab tool of claim 2, wherein, The material of the scraper blade (9) is selected according to the well conditions, including film.

8. A method for composite wellhead swabbing without switchover, characterized in that, Use tubing to expand the expansion block (4) to the well-through condition. At this time, insert the central tube (1) and the expansion block (4) expands. When the tubing string is pulled out after the construction is completed, unload the tubing according to the normal procedure. When the tubing is seen, pull out the central tube (1) first, and the expansion block (4) can be returned to the free state to avoid the tool getting stuck at the wellhead.

9. The method of claim 8, wherein, The oil pipe is a 2.5-inch oil pipe.

10. The method of claim 8, wherein, Before the wellbore is opened, the expansion block (4) is expanded using tubing, and a 3-inch tubing connection tool is used.

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