Milling cylinder for petroleum well repair

Abstract

The utility model relates to the technical field of petroleum well repair accessories, and discloses a casing milling barrel for petroleum well repair, which comprises a barrel body, a reinforcing connecting mechanism is arranged outside the barrel body, a falling object fishing mechanism is fixedly connected inside the barrel body, the falling object fishing mechanism comprises a centralizing column, a plurality of guide grooves are formed outside the centralizing column, and the centralizing column is fixedly connected with the reinforcing connecting mechanism. A plurality of guide grooves are formed in the cylinder body, a plurality of rolling balls are arranged outside the righting column, the outer portions of the rolling balls are slidably connected to the interior of the cylinder body, and the bottom of the righting column is fixedly connected with an elastic grabbing clamp. According to the utility model, the righting column and the rolling ball outside the righting column roll in the guide groove inside the barrel, so that the righting column is always positioned at the central position of the barrel, and further, the wave-shaped milling head can stably cut falling objects, so that the falling objects can be uniformly and effectively crushed, and a good foundation is laid for subsequent fishing work.

Description

Technical Field

[0001] This utility model relates to the field of oil well workover accessories technology, and in particular to a milling sleeve for oil well workover. Background Technology

[0002] Against the backdrop of continuously rising global energy demand, oil, as a vital energy resource, requires crucial extraction and maintenance. Oil well workover operations are a key link in ensuring the long-term stable production of oil wells, and the milling sleeve, as one of the core tools in oil well workover operations, shoulders the important mission of removing debris from the well and repairing the wellbore. As oil extraction advances into deeper and more complex formations, the downhole environment becomes increasingly complex and changeable, placing higher demands on the performance and reliability of the milling sleeve.

[0003] The existing oil well workover sleeves operate on a relatively basic principle. They are connected to the tubing string and driven to rotate by surface equipment. The milling head at the lower end of the sleeve cuts and grinds debris inside the well. During rotation, the debris is broken into small pieces and carried out of the wellhead with the circulating drilling fluid, thus clearing obstacles from the well.

[0004] In existing technologies, due to complex downhole geological conditions and uneven well walls, the milling sleeve is prone to deviation and wobbling during the rotary cutting process, resulting in unstable contact between the milling head and the fallen object, reducing cutting efficiency, prolonging operation time, increasing operation costs, and causing the fallen object to remain, increasing the difficulty of subsequent retrieval. To address these issues, a milling sleeve for oil well workover is proposed. Utility Model Content

[0005] To overcome the above deficiencies, this utility model provides a milling sleeve for oil well workover, which aims to improve the problem of shaking in some devices in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A milling sleeve for oil well workover includes a sleeve body, a reinforcing connection mechanism on the outside of the sleeve body, a debris retrieval mechanism fixedly connected inside the sleeve body, a wave milling head fixedly connected to the bottom of the debris retrieval mechanism, the wave milling head having a ramp, the debris retrieval mechanism including a straightening column, the straightening column being slidably connected to the outside of the sleeve body, the straightening column having multiple guide grooves on the outside, the sleeve body having multiple guide grooves, the straightening column having multiple rolling balls on the outside, the rolling balls being slidably connected to the outside of the sleeve body, and an elastic gripper fixedly connected to the bottom of the straightening column.

[0008] As a further description of the above technical solution:

[0009] The reinforcing connection mechanism includes a hydraulic column, which is externally fixedly connected to the outside of the cylinder, and a reinforcing plate is fixedly connected to the drive end of the hydraulic column.

[0010] As a further description of the above technical solution:

[0011] The bottom of the elastic gripper is fixedly connected to an inward-turning filter plate, and a connecting ring is slidably connected to the outside of the inward-turning filter plate.

[0012] As a further description of the above technical solution:

[0013] A buffer spring is fitted between the reinforcing plate and the cylinder, i.e., on the outside of the hydraulic column;

[0014] As a further description of the above technical solution:

[0015] The top of the cylinder is provided with a threaded connection port;

[0016] As a further description of the above technical solution:

[0017] A wave milling head is provided at the bottom of the cylinder, and a ramp is provided on the opposite side of the wave milling head.

[0018] This utility model has the following beneficial effects:

[0019] 1. In this utility model, by having the centering column and its external rolling ball roll in the guide groove inside the cylinder, the centering column is always kept in the center position of the cylinder, thereby enabling the wave milling head to stably cut the falling object. This avoids the reduction in milling efficiency or equipment damage caused by shaking, ensures the quality of the milling operation, and enables the falling object to be broken evenly and effectively, laying a good foundation for subsequent retrieval work.

[0020] 2. In this utility model, the milling sleeve is firmly connected to the workover string through the threaded connection port, ensuring that it will not fall off during the lifting and lowering process. During the lowering process, the hydraulic column initially contracts and the buffer spring is in a compressed state, which can effectively absorb the impact force generated by the collision with the well wall. This greatly improves the stability of the milling sleeve during the lowering process, reduces the risk of equipment damage due to collision, ensures the integrity and service life of the milling sleeve, and reduces maintenance and replacement costs. Attached Figure Description

[0021] Figure 1 This is a three-dimensional schematic diagram of a milling sleeve for oil well workover proposed in this utility model;

[0022] Figure 2 This is a schematic diagram of the structure of a centralizing column for a milling sleeve used in oil well workover according to the present invention;

[0023] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0024] Figure 4 for Figure 2 Enlarged view of point B in the middle:

[0025] 1. Cylinder body; 2. Wave milling head; 3. Dropping object retrieval mechanism; 301. Straightening column; 302. Rolling ball; 303. Elastic gripper; 304. Inward-turning filter plate; 305. Connecting ring; 4. Threaded connection port; 5. Reinforcing connection mechanism; 501. Reinforcing plate; 502. Hydraulic column; 503. Buffer spring; 6. Ramp. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Reference Figures 1 to 3 This utility model provides an embodiment of a milling sleeve for oil well workover, including a sleeve body 1. The sleeve body 1 is the main load-bearing structure of the milling sleeve, providing an installation foundation for other internal and external components. During operation, it withstands various forces such as pressure and torque from downhole, ensuring the integrity of the entire milling sleeve structure and guaranteeing the smooth progress of well workover operations. A reinforcing connection mechanism 5 is provided on the outside of the sleeve body 1, and a debris retrieval mechanism 3 is fixedly connected inside the sleeve body 1. A wave milling head 2 is fixedly connected to the bottom of the debris retrieval mechanism 3. During milling operations, the wave milling head 2, with its unique wave structure, can significantly increase the contact area with downhole debris compared to traditional milling heads, improve cutting and crushing efficiency, and make the debris be processed into small pieces that are easy to retrieve more quickly. The wave milling head 2 is provided with a ramp 6.

[0028] The object retrieval mechanism 3 includes a centering column 301, which can slide flexibly within the cylinder 1 and adjust its position in real time. During milling operations, it ensures that the entire object retrieval mechanism 3 and the connected wave milling head 2 are always centered in the wellbore, preventing uneven milling or tool damage due to eccentricity and ensuring the stability of the milling operation. The centering column 301 is externally slidably connected to the inside of the cylinder 1. Multiple guide grooves are provided on the outside of the centering column 301 and inside the cylinder 1. Multiple rolling balls 302 are provided on the outside of the centering column 301, positioned between the centering column 301 and the cylinder 1. These rolling balls convert the original sliding friction into rolling friction, reducing the frictional force during relative movement and making the sliding of the centering column 301 within the cylinder 1 easier and more flexible. This also reduces component wear and extends the lifespan of the wellbore. To extend the service life of the equipment, the rolling ball 302 is externally slidably connected to the inside of the cylinder 1. The bottom of the straightening column 301 is fixedly connected to an elastic gripper 303. When the object enters its effective range, the elastic gripper 303 uses its own elastic deformation characteristics to firmly grasp the object, preventing the grabbed object from falling back into the well. This ensures that the retrieved object can be safely stored in the milling sleeve, improving the retrieval success rate. The bottom of the elastic gripper 303 is fixedly connected to an inward-turning filter plate 304. The inward-turning filter plate 304 performs preliminary screening and filtering of the object entering the milling sleeve from below, allowing only objects of suitable size to pass through and enter deeper into the milling sleeve. This prevents excessively large debris from clogging the internal space of the milling sleeve and affecting subsequent operations, ensuring the smoothness of the object retrieval process. The inward-turning filter plate 304 is externally slidably connected to a connecting ring 305.

[0029] Reference Figure 1 , Figure 2 and Figure 4The reinforcement connection mechanism 5 includes a hydraulic column 502, which is externally fixed to the outside of the cylinder 1. A reinforcement plate 501 is fixedly connected to the drive end of the hydraulic column 502. The reinforcement plate 501 is in direct contact with the well wall, and its material and surface treatment ensure high wear resistance and high strength, evenly distributing the pressure on the cylinder 1 and preventing localized damage to the well wall. A buffer spring 503 is sleeved between the reinforcement plate 501 and the cylinder 1, i.e., on the outside of the hydraulic column 502. When encountering downhole vibration and impact, the buffer spring 503 can elastically deform to absorb energy, reducing the impact on the cylinder 1 and its internal components. The buffer reinforcement plate 501 reduces the squeezing pressure on the well wall, protecting the well wall and equipment. The top of the cylinder 1 is provided with a threaded connection port 4, and the bottom of the cylinder 1 is provided with a wave milling head 2. The wave milling head 2 rotates under the drive of the cylinder 1. The unique wave shape increases the contact area with the falling object, resulting in high cutting efficiency and uniform cutting force distribution, reducing its own wear, extending service life, and accelerating the breaking of the falling object. The opposite side of the wave milling head 2 is provided with a ramp 6, which can guide the cutting fragments to move into the cylinder 1, preventing the fragments from accumulating. When cutting hard falling objects, it plays a wedging role, enhancing the breaking capacity and improving the milling operation effect.

[0030] Working principle: The milling sleeve is firmly connected to the workover string through the threaded connection port 4 at the top of the cylinder 1. Then, the milling sleeve is slowly lowered along the wellbore using the hoisting equipment. During this process, the hydraulic column 502 is in the initial contracted state, and the buffer spring 503 between the reinforcing plate 501 and the cylinder 1 is in the compressed state. This can effectively absorb the impact force generated by the collision with the well wall during the lowering process, ensuring that the milling sleeve is lowered smoothly and avoiding damage.

[0031] Once the milling sleeve reaches the predetermined position downhole, the surface equipment drives the workover string to rotate, causing the sleeve 1 and the wave milling head 2 to rotate together. The unique wave design and ramp 6 of the wave milling head 2 increase the contact area with the downhole debris during rotation, improving cutting efficiency and rapidly breaking up the debris. During the milling process, the centralizing column 301 and its external rolling ball 302 roll within the guide groove inside the sleeve 1, ensuring that the centralizing column 301 remains at the center of the sleeve 1. This ensures that the wave milling head 2 stably cuts the debris, preventing a decrease in milling efficiency due to shaking. Or damage the equipment. At the same time, as the falling object is gradually cut and broken, the debris begins to move into the cylinder 1. When the debris comes into contact with the elastic gripper 303, the elastic gripper 303 will deform due to compression, tightly clamping the debris and preventing it from falling again. Meanwhile, the inward-turning filter plate 304 can perform preliminary filtration of larger falling object fragments. Only fragments that meet the size requirements can pass through the inward-turning filter plate 304 and enter the cylinder 1. The connecting ring 305 can adjust the position of the inward-turning filter plate 304 according to the actual situation, control the filtration size, and adapt to falling objects of different sizes.

[0032] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A milling sleeve for oil well workover, comprising a sleeve body (1), characterized in that: The cylinder (1) is provided with a reinforcing connection mechanism (5) on the outside, and a falling object retrieval mechanism (3) is fixedly connected inside the cylinder (1). A wave milling head (2) is fixedly connected to the bottom of the falling object retrieval mechanism (3), and the wave milling head (2) is provided with a ramp (6). The object retrieval mechanism (3) includes a straightening column (301), which is slidably connected to the outside of the cylinder (1). The outside of the straightening column (301) is provided with multiple guide grooves, and the inside of the cylinder (1) is provided with multiple guide grooves. The outside of the straightening column (301) is provided with multiple rolling balls (302), which are slidably connected to the outside of the cylinder (1). An elastic gripper (303) is fixedly connected to the bottom of the straightening column (301).

2. The oil well workover sleeve according to claim 1, characterized in that: The reinforcing connection mechanism (5) includes a hydraulic column (502), which is fixedly connected to the outside of the cylinder (1), and a reinforcing plate (501) is fixedly connected to the driving end of the hydraulic column (502).

3. A milling sleeve for oil well workover according to claim 1, characterized in that: The bottom of the elastic gripper (303) is fixedly connected to an inward-turning filter plate (304), and a connecting ring (305) is slidably connected to the outside of the inward-turning filter plate (304).

4. A milling sleeve for oil well workover according to claim 2, characterized in that: A buffer spring (503) is sleeved on the outside of the hydraulic column (502) between the reinforcing plate (501) and the cylinder (1).

5. A milling sleeve for oil well workover according to claim 1, characterized in that: The top of the cylinder (1) is provided with a threaded connection port (4).

6. A milling sleeve for oil well workover according to claim 1, characterized in that: The bottom of the cylinder (1) is provided with a wave milling head (2), and a ramp (6) is provided on the opposite side of the wave milling head (2).

Images