Falling object salvaging device with undersize drift diameter

Abstract

The invention belongs to the field of conventional workover treatment processes and matched technologies, particularly relates to an over-small-drift-diameter falling object fishing device, and aims to solve the problems that falling objects are extremely difficult to fish in a well with a large production casing drift diameter and a small wellhead four-way drift diameter, and risks and limitations exist in an existing solution. According to the device, one end of a bent short section is connected with an oil pipe, the other end of the bent short section is connected with one end of a fishing tool, the other end of the fishing tool is connected with one end of a wall hook, and the other end of the wall hook is provided with a guiding shoe which extends out in the radial direction of a shaft to centralize a fish top; the guiding shoe is matched with well mouths of different sizes by being bent by different angles, and the guiding shoe is used for centralizing underground fish and guiding the underground fish into a fishing tool. The device can adapt to well mouths of different sizes, fallen objects can be fished without replacing the well mouths, the construction risk and cost are reduced, and the operation efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of conventional well workover operation technology and supporting technology, and specifically relates to a device for retrieving objects with excessively small diameter. Background Technology

[0002] Currently, major oilfields are successively entering the middle and late stages of exploitation, and the condition of oil and water wells is deteriorating day by day. Accidents such as objects falling into the well are increasing year by year. Complex situations such as sand from the formation blocking the tubing string, objects falling into the well making it impossible to retrieve fish tops, and objects falling into the annular space between the tubing string and casing are frequently encountered. These situations increase the difficulty of retrieving objects from the well and add to the construction process. If not handled properly during construction, sand can easily cause the retrieval tubing string to get stuck in the well, increasing the construction period and creating an unmanageable situation that prevents the oil and water wells from producing normally.

[0003] To restore normal production in oil and water wells, downhole operations are crucial, thus creating an increasingly urgent need for retrieval tools. However, existing tools for handling wellbore surfaces and retrieving fallen fish rely on the premise that the wellhead cross-section and casing inner diameter are identical.

[0004] Some wells have large-diameter production casings due to completion methods, while the wellhead uses smaller-diameter four-way connectors and wellheads. Retrieving debris from such wells is difficult. The current solution is to replace the small-diameter wellhead with a larger one that matches the casing's inner diameter. However, in some cases, temporary well closure cannot be achieved before replacing the wellhead, and replacing the wellhead under uncontrollable circumstances carries certain risks.

[0005] Based on this, the present invention proposes a device for retrieving objects with excessively small diameter. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, namely the frequent occurrence of falling objects due to deteriorating downhole conditions in the middle and late stages of oil and water well production, especially in wells with large production casing diameters and small wellhead four-way diameters, where object retrieval is extremely difficult, and existing solutions (such as replacing the wellhead) have risks and limitations, this invention provides a device for retrieving falling objects with excessively small diameters, including a bent short section and a wall hook.

[0007] One end of the bent short section is connected to the tubing, and the other end of the bent short section is connected to one end of the fishing tool. The other end of the fishing tool is connected to one end of the wall hook. The other end of the wall hook is provided with a guide shoe that extends radially along the wellbore to straighten the top of the fish. The guide shoe is matched with wellheads of different sizes by bending at different angles. The guide shoe is used to straighten the fish that has fallen into the well and guide the fish into the fishing tool.

[0008] In some preferred embodiments, the bent section includes a coupling, a bent section, and a first connecting section;

[0009] The coupling is used to connect the oil pipe. The coupling is fixed to one end of the bent section. The other end of the bent section is provided with a first connecting section, which is used to connect one end of the salvage tool.

[0010] The bending section is configured with different bending angles according to the diameter of the sleeve.

[0011] In some preferred embodiments, the wall hook includes a second connecting section, a wall hook body, and a guide groove;

[0012] The second connecting section is used to connect and communicate with the other end of the retrieval tool. The second connecting section is fixed to one end of the wall hook body, and the other end of the wall hook body is fixed to the guide shoe. A bending angle is set between the guide shoe and the wall hook body, and the bending angle is set based on the wellhead diameter.

[0013] The wall hook body is provided with a guide groove, which is connected to the retrieval tool. The guide groove is used to guide the fish that has fallen into the well to the retrieval tool.

[0014] In some preferred embodiments, the width of the guide groove gradually increases from the second connecting section to the guide shoe.

[0015] In some preferred embodiments, the maximum bend position is smaller than the wellhead diameter.

[0016] In some preferred embodiments, the bending direction of the bent sub when it enters the well is the same as the bending direction of the guide shoe.

[0017] In some preferred embodiments, the first connecting segment is a thread.

[0018] In some preferred embodiments, the second connecting segment is a female buckle.

[0019] The beneficial effects of this invention are:

[0020] Improve retrieval efficiency: By using the combination of the bent short section and the wall hook, it can be ensured that the falling object (especially the falling object close to the casing wall) can be effectively guided and accurately introduced into the retrieval tool, thereby improving the success rate and efficiency of retrieval.

[0021] High adaptability: The guide shoe of this device can be adjusted to adapt to wellheads of different sizes by adjusting the bending angle, so that fishing operations can be carried out smoothly even when the wellhead diameter is small, which enhances the versatility and adaptability of the device.

[0022] Reduced construction risks: It avoids the risks associated with replacing the wellhead in traditional methods, such as well control problems that may result from failure of temporary well closure, and reduces uncertainty and potential safety hazards during the operation.

[0023] Simplified operation process: Compared with complex measures such as replacing the wellhead, the operation of this device is simpler and faster, and it can be quickly deployed to the site, shortening the processing time and reducing construction costs.

[0024] Protecting the downhole environment: Completing the salvage operation without damaging the original downhole structure helps maintain the stability of the downhole environment and reduces the impact on oil and water well production. Attached Figure Description

[0025] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0026] Figure 1 This is a schematic diagram illustrating the use of a device for retrieving objects with a small diameter according to the present invention.

[0027] Figure 2 This is a schematic diagram of the bent short section in a small-diameter object retrieval device of the present invention;

[0028] Figure 3 This is a front view of the wall hook in a small-diameter object retrieval device according to the present invention;

[0029] Figure 4 This is a side view of the wall hook in a small-diameter object retrieval device according to the present invention;

[0030] Figure 5 This is a schematic diagram comparing various parameters of the well before and after use in a short section of a small-diameter object retrieval device according to the present invention. Detailed Implementation

[0031] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] like Figures 1-4 As shown, the present invention provides a device for retrieving objects with a small diameter, including a bent short section 1 and a wall hook 2;

[0034] One end of the bent short section 1 is connected to the tubing 3, and the other end of the bent short section 1 is connected to one end of the fishing tool 4. The other end of the fishing tool 4 is connected to one end of the wall hook 2. The other end of the wall hook 2 is provided with a guide shoe 5 extending radially along the wellbore to straighten the top of the fish. The guide shoe 5 is matched with wellheads of different sizes by bending at different angles. The guide shoe 5 is used to straighten the fish 6 that has fallen into the well and guide the fish 6 into the fishing tool 4.

[0035] The present invention includes the following steps when used:

[0036] Preliminary preparations: First, based on the actual size of the wellhead and the situation of the falling object, it is necessary to select the appropriate angles of the curved short section 1 and the guide shoe 5.

[0037] Assemble the equipment: Assemble the bent short section 1, the salvage tool 4, and the wall hook 2, and check that all connection points are firm and reliable.

[0038] Lowering the equipment: The assembled salvage device is slowly lowered to the predetermined depth via tubing 3. During this process, operators must closely monitor the descent of the equipment to avoid unnecessary collisions with the wellbore.

[0039] Salvage operation: When the salvage tool 4 approaches the target location, the falling object is accurately guided into the capture range of the salvage tool 4 by using the guiding effect of the wall hook 2 and the guide shoe 5.

[0040] Recovery device: After confirming that the fish 6 that fell into the well has been firmly grasped, slowly raise the entire retrieval device to the surface. During this process, it is also necessary to operate smoothly to prevent the fish from falling off.

[0041] In this embodiment, the downhole fish 6 can be illustrated by taking a fish as an example. The bent section 1 in this invention is bent at different angles according to the casing diameter by a bending machine, so that the retrieval tool 4 below it is close to the casing wall. Since the top of the fish is leaning against the casing wall in the well, the tubing 3 is slowly rotated when the fish top is reached, so that the guide shoe 5 straightens the fish top. During the rotation, the tubing slowly moves downward, and while straightening the fish top, it guides the fish top into the retrieval tool until the retrieval is successful.

[0042] The bending direction of the bent section 1 when it enters the well is the same as the bending direction of the guide shoe 5.

[0043] For further explanation of the present invention, see [link to relevant documentation]. Figure 1 and Figure 2 The bent short section 1 includes a coupling 11, a bent section 12, and a first connecting section 13;

[0044] The coupling 11 is used to connect the oil pipe 3. The coupling is fixed to one end of the bent section 12. The other end of the bent section 12 is provided with a first connecting section 13. The first connecting section 13 is used to connect one end of the salvage tool 4.

[0045] The bending section 12 is configured with different bending angles according to the diameter of the sleeve.

[0046] In this embodiment, coupling 11 is part of the bent short section 1 and is mainly used for connection with oil pipe 3. The design of coupling 11 must ensure that the connection with oil pipe 3 is both tight and reliable, and a threaded connection is usually adopted. The inner diameter of coupling 11 should match the outer diameter of oil pipe 3 to ensure good sealing performance.

[0047] The bend section 12 is the core part of the bent sub 2, and its main function is to provide a flexible transition between the tubing 3 and the fishing tool 4. The bending angle of the bend section 12 can be adjusted according to the wellhead diameter in actual application to adapt to wellheads of different sizes, so that the fishing tool 4 below it is close to the inner wall of the casing and the guide shoe is tightly attached to the inner wall of the casing.

[0048] The first connecting segment 13 is located at the other end of the bent segment 12 and is used to connect to one end of the salvage tool 4. In this embodiment, the first connecting segment 13 is threaded to ensure a secure connection with the salvage tool 4 and to facilitate disassembly and replacement. The advantages of threaded connection are that it is simple, reliable, and can be quickly adjusted on-site.

[0049] For further explanation of the present invention, see [link to relevant documentation]. Figure 3 and Figure 4 The wall hook 2 includes a second connecting section 21, a wall hook body 22, and a guide groove 23;

[0050] The second connecting section 21 is used to connect and communicate with the other end of the retrieval tool 4. The second connecting section 21 is fixed to one end of the wall hook body 22, and the other end of the wall hook body 22 is fixed to the guide shoe 5. A bending angle is set between the guide shoe 5 and the wall hook body 22, and the bending angle is set based on the wellhead diameter.

[0051] The wall hook body 22 is provided with a guide groove 23, which is connected to the retrieval tool 4. The guide groove 23 is used to guide the fish 6 that has fallen into the well to the retrieval tool 4.

[0052] The second connecting segment 21 is a female buckle.

[0053] The wall hook 2 of this invention includes the following features during use:

[0054] Connect the second connecting section 21 to the other end of the salvage tool 4 to ensure that the female buckle and the male buckle in the salvage tool 4 are tightly and reliably connected.

[0055] One end of the wall hook body 22 is fixed to the second connecting section 21, and the other end is fixed to the guide shoe 5.

[0056] Check all connections to ensure they are secure and will not loosen during the salvage operation.

[0057] The width of the guide groove 23 gradually increases from the second connecting section 21 to the guide shoe 5.

[0058] The function of the guide groove 23 with varying width in this invention is as follows:

[0059] Improved guidance accuracy: Initial guidance: When the retrieval tool approaches the falling object, the narrower guide slot inlet can more accurately guide the falling object into the guide slot, reducing the possibility of the falling object deviating.

[0060] Gradual expansion: As the object gradually enters the guide groove, the gradually increasing width design can better adapt to changes in the shape and position of the object, ensuring that the object can smoothly enter the capture range of the retrieval tool.

[0061] Reduce the risk of jamming: In the initial stage, a narrower guide groove inlet can prevent larger foreign objects or debris from entering, reducing the risk of jamming.

[0062] Subsequent stages: The design with gradually increasing width can accommodate larger or irregularly shaped objects, avoiding jamming caused by the guide groove being too narrow.

[0063] Enhanced adaptability: Different sized objects: The guide groove with gradually increasing width can accommodate objects of different sizes and shapes, improving the versatility and adaptability of the retrieval tool.

[0064] Changes in the downhole environment: The downhole environment is complex and ever-changing. Guide slots with gradually increasing width can better cope with various obstacles that may exist downhole, ensuring the smooth progress of the salvage process.

[0065] Improve retrieval efficiency: rapid positioning: the narrower guide slot inlet can help to quickly locate the fallen object, improving the initial accuracy of retrieval.

[0066] Smooth guidance: The gradually increasing width design ensures that objects fall more smoothly into the retrieval tool, reducing the time spent on repeated adjustments and repositioning, and improving retrieval efficiency.

[0067] Reduced wear: Initial contact: A narrower guide groove inlet can reduce the contact area between the falling object and the guide groove, thus reducing wear.

[0068] After the fish 6 that has fallen into the well is righted by the guide shoe 5, the oil pipe 3 is moved downward so that the top of the fish enters the guide groove 23. It continues to move downward so that the fish 6 falls into the well along the guide groove 23 and enters the retrieval tool 4.

[0069] For further explanation of the present invention, see [link to relevant documentation]. Figure 1 When the guide shoe 5 is rotated to its maximum angle, it does not contact the wellhead. In other words, the guide shoe 5 can bend outward according to the well's diameter, and can be bent to a maximum size slightly smaller than the wellhead diameter. During retrieval, the retrieval position is continuously changed by rotating the tubing 3, thereby straightening the top of the fish and smoothly guiding it into the fish cavity; thus achieving the retrieval of the fallen fish.

[0070] For further explanation of the present invention, see [link to relevant documentation]. Figure 2 The bent section 12 is made by integrally forming and bending a tubular structure.

[0071] This invention has been successfully used for salvage operations in practice, for example:

[0072] See Figure 5 On June 12, 2023, a certain well suddenly experienced abnormal production. By June 28, 2023, the daily fluid production had dropped to 15 tons, while the water cut had increased to 33.2%. On the morning of June 29, 2023, it was discovered that the well was not producing fluid despite oil gauging, and no samples were taken from the wellhead. Around 5 PM that afternoon, oil gauging was conducted again, with a daily fluid production of 22 tons, leading to suspicion that the well had begun intermittent fluid production. To verify the condition of the tubing within the well, pressure tests were conducted twice, on June 26 and June 28, 2023, both encountering resistance at 1050 meters. On June 30, 2023, well depth calibration was performed, revealing that the tubing had fallen into the well near 950 meters.

[0073] After the work team retrieved the casing, they discovered that the well's production casing was D244.5mm with an inner diameter of 222.4mm, while the well's main cross-section diameter was only 160mm. This size limitation made retrieval difficult. Upon retrieving the original well, the work team found that the 97th tubing section was broken. Using a DLT-T114 basket-type retractable retrieval tube (with a D148mm guide shoe) and 109 tubing sections with a D73.02mm external thickening, the retrieval reached a depth of 1060.08m after a 9.15m entry with resistance indication. One additional tubing section was added, and the retrieval was slowly rotated and lowered under 20kN pressure. Upon lifting, the suspended weight remained unchanged, and repeated retrieval attempts yielded no results.

[0074] Analysis revealed that the tubing break diameter was D73mm, and the guide shoe outer diameter was 148mm, totaling 221mm. The casing diameter was 222.4mm, which could be missed. Since the standard guide shoe outer diameter could be offset within the casing, a custom-made D155mm wall hook, a DLT-T114 basket-type retractable retrieval tube, a bent short section, and tubing were used for retrieval at a depth of 1055.29m. The tubing was slowly lowered by rotation, pressurized to 30kN, and then lifted with a suspended weight from 90kN to 480kN, before suddenly dropping to 400kN. Further lifting was successful without any sticking. A D73.02mm thickened tubing was then pulled at a limited speed, retrieving all the tubing that had fallen into the well and bringing out the tubing shoe. This provided complete wellbore conditions for subsequent steps. After production commenced, the well has been stable, currently producing 31t of fluid and 25.57t of oil per day.

[0075] In the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0076] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0077] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0078] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A device for retrieving objects with excessively small diameter, characterized in that, Includes a bent short section (1) and a wall hook (2); One end of the bent short section (1) is connected to the tubing (3), and the other end of the bent short section (1) is connected to one end of the fishing tool (4). The other end of the fishing tool (4) is connected to one end of the wall hook (2). The other end of the wall hook (2) is provided with a guide shoe (5) that extends radially along the wellbore to straighten the top of the fish. The guide shoe (5) is matched with wellheads of different sizes by bending at different angles. The guide shoe (5) is used to straighten the fish (6) that has fallen into the well and to guide the fish (6) into the fishing tool (4).

2. The device for retrieving objects with excessively small diameter as described in claim 1, characterized in that, The bent short section (1) includes a coupling (11), a bent section (12), and a first connecting section (13); The coupling (11) is used to connect the oil pipe (3). The coupling is fixed to one end of the bent section (12). The other end of the bent section (12) is provided with a first connecting section (13). The first connecting section (13) is used to connect one end of the salvage tool (4). The bending section (12) is set with different bending angles according to the diameter of the sleeve.

3. The device for retrieving objects with a small diameter as described in claim 1, characterized in that, The wall hook (2) includes a second connecting section (21), a wall hook body (22), and a guide groove (23); The second connecting section (21) is used to connect and communicate with the other end of the retrieval tool (4). The second connecting section (21) is fixed to one end of the wall hook body (22). The other end of the wall hook body (22) is fixed to the guide shoe (5). A bending angle is set between the guide shoe (5) and the wall hook body (22). The bending angle is set based on the wellhead diameter. The wall hook body (22) is provided with a guide groove (23), which is connected to the retrieval tool (4). The guide groove (23) is used to guide the fish (6) that fell into the well to the retrieval tool (4).

4. The device for retrieving objects with excessively small diameter as described in claim 3, characterized in that, The width of the guide groove (23) gradually increases from the second connecting section (21) to the guide shoe (5).

5. The device for retrieving objects with an excessively small diameter as described in claim 3, characterized in that, The maximum bending point is smaller than the wellhead diameter.

6. The device for retrieving objects with an excessively small diameter as described in claim 1, characterized in that, The bending direction of the bent section (1) when it enters the well is the same as the bending direction of the guide shoe (5).

7. The device for retrieving objects with an excessively small diameter according to claim 2, characterized in that, The first connecting segment (13) is a thread.

8. A device for retrieving objects with an excessively small diameter as described in claim 3, characterized in that, The second connecting segment (21) is a female buckle.

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