A floating collar

Abstract

The application provides a floating collar, which comprises an outer cylinder, an upper joint arranged at the upper end of the outer cylinder, a lower joint arranged at the lower end of the outer cylinder, a rupture member arranged in the inner part of the outer cylinder in a sealed and fixed manner, and a striking assembly arranged in the inner part of the outer cylinder and below the rupture member, wherein the striking assembly is configured to strike the rupture member under the action of pressure. The application can realize the full gauge of the pipe string after the rupture member is broken, reduce the construction risk, and has the characteristics of simple structure and convenient construction.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas drilling, completion and reservoir stimulation technology, specifically, it relates to a floating coupling. Background Technology

[0002] During the development of oil and gas wells, as exploration and development deepen, oil and gas wells face problems such as large water-to-vertical ratio and insufficient self-weight of tubing due to long horizontal sections, resulting in large frictional torque in the horizontal section and difficulty in lowering the tubing when it is lowered.

[0003] The floating coupling casing technology effectively solves the challenge of running completion tubing in wells with extended reach and long horizontal sections. This technology involves sealing a section of air or low-density drilling fluid at the bottom of the casing string using a floating coupling, allowing the casing string to float in the drilling mud of the inclined or horizontal sections of the well. This reduces friction between the casing string and the wellbore. After the casing string is in place, the sealed section is then opened to ensure unobstructed flow inside the casing string.

[0004] In existing technologies, there is a type of floating coupling with a fractured component. This type of coupling seals off a section of air or low-density drilling fluid using a fractured component. After the tubing string is in place, the fractured component is broken by direct pressure buildup. However, this pressure buildup method may result in incomplete fracture of the component, meaning the tubing string may not reach full bore. Incomplete fracture can affect the passage performance of the cement plug during subsequent operations. The cement plug may be damaged by the remaining fractured component, preventing effective scraping of residual cement in the tubing string. This increases the actual opening pressure of tools such as the pre-installed differential pressure sleeve in the tubing string and reduces the safety of other tools passing through, increasing construction risks. Furthermore, it may completely destroy the cement plug, causing it to fail due to pressure contact and seal failure, leading to cement backflow into the wellbore and creating complex wellbore conditions.

[0005] In addition, another type of floating coupling with a sliding sleeve and a fracture element exists in the existing technology. This type of floating coupling has a movable fracture element and a fixed impact sleeve inside, with a fracture disc positioned above the impact sleeve. The impact sleeve and the fracture element are then fixed together by shear pins. When it is necessary to fracture the fracture element, pressure is pumped from above the fracture disc, pushing the fracture element to shear the shear pins and impact the impact sleeve, thus completely fracturing the fracture element. Although this technology can achieve full-bore tubing, it is essential to ensure that the fracture element does not shift relative to the main tubing of the floating coupling during the running-in process. In this structure, a large number of shear pins must be used to fix the fracture element and ensure its normal operation during running-in. Therefore, this structure requires a large number of shear pins, which are difficult to control. Moreover, they are often distributed in multiple rows, which may cause uneven stress on the pins under the pressure of the drilling mud, leading to premature shearing, process failure, and failure of the tubing to be successfully run into place. The use of multiple shear pins results in extremely high pumping pressure during the crushing of the broken parts. Since the broken parts are subjected to pressure to shear the shear pins, such pumping pressure may cause the broken parts to break prematurely. If the broken parts break before the shear pins break due to unforeseen circumstances or if the seal fails, the shear pins will not be able to cut through, preventing the broken parts from hitting the impact sleeve. This may prevent the tubing string from achieving full bore, affecting subsequent work and increasing operational risks. Summary of the Invention

[0006] To address the technical problems described above, this invention aims to provide a floating coupling that can achieve full bore of the tubing, thereby reducing the risk of operational accidents.

[0007] According to the present invention, a floating coupling is provided, comprising: an outer cylinder; an upper connector disposed at the upper end of the outer cylinder; a lower connector disposed at the lower end of the outer cylinder; a rupture element disposed in a sealed manner inside the outer cylinder; and an impact assembly disposed inside the outer cylinder, the impact assembly being disposed below the rupture element, the impact assembly being configured to impact the rupture element under pressure.

[0008] In one embodiment, the impact assembly includes an inner sleeve that is sealed and fixedly connected to the outer cylinder and an impact sleeve that is fixed to the inner sleeve by a shear pin.

[0009] In one embodiment, a C-shaped ring is provided on the outer wall of the inner sleeve, and a groove that mates with the C-shaped ring is provided on the inner wall of the outer cylinder.

[0010] In one embodiment, the impact sleeve includes a convex ring portion and an impact portion, the wall thickness of the convex ring portion is greater than the wall thickness of the impact portion, the convex ring portion is sealed to the outer cylinder, and the inner sleeve is sealed between the impact portion and the outer cylinder.

[0011] In one embodiment, a positioning protrusion for mounting the fracture component is provided inside the outer cylinder, and a positioning end face is provided on the positioning protrusion. The lower end of the fracture component abuts against the positioning end face, and the upper end of the fracture component abuts against the upper connector.

[0012] In one embodiment, the upper end of the lower connector extends into the interior of the outer cylinder and abuts against the impact assembly.

[0013] In one embodiment, a step is provided on the lower inner wall of the upper connector.

[0014] In one embodiment, a sealing structure is provided on the ruptured component, wherein the sealing structure is a single-sided seal or a multi-sided seal.

[0015] In one embodiment, the fractured component is made of a high-pressure resistant, brittle non-metallic material, which includes glass, ceramics, and resin.

[0016] In one embodiment, the ruptured component is cylindrical or spherical.

[0017] Compared with the prior art, this application has the following advantages.

[0018] This invention isolates the drilling mud during tubing string insertion by using a fracturing element. A section of air or low-density drilling fluid is sealed between the floating coupling and the tubing string below, utilizing buoyancy to reduce the weight of the tubing string entering the inclined or horizontal section of the well, thereby reducing tubing string insertion friction and facilitating smooth insertion. In this invention, the fracturing element is fixedly located inside the outer cylinder. The impact sleeve has a small axial pressure area, requiring only a few shear pins to be fixed inside the outer cylinder via the inner sleeve, reducing the difficulty of pin control. During the fracturing process, the impact sleeve utilizes the pressure difference between its upper and lower end faces to achieve displacement, shearing the shear pins and impacting the fracturing disc. The fragments are then carried out through circulation. With this setup, even if the fracturing element fails prematurely, the impact sleeve can still complete displacement under pressure and impact the fracturing element. This invention achieves full-bore tubing insertion after fracturing, reduces construction risks, and features a simple structure and convenient construction. Attached Figure Description

[0019] The invention will now be described with reference to the accompanying drawings.

[0020] Figure 1 A schematic diagram of the initial state of an embodiment of the floating coupling according to the present invention is shown;

[0021] Figure 2 This shows a schematic diagram of a broken component after one embodiment of the floating coupling according to the present invention.

[0022] Figure 3A schematic diagram of another embodiment of the crushing disc according to the present invention is shown;

[0023] Figure 4 A schematic diagram showing the inner sleeve and outer sleeve connected by pins according to the present invention is provided.

[0024] In the figure: 1. Outer cylinder; 11. Positioning protrusion; 111. Positioning end face; 2. Upper connector; 21. Step; 3. Lower connector; 4. Fragment; 41. Sealing structure; 5. Impact assembly; 51. Inner sleeve; 511. C-ring; 512. Groove; 52. Impact sleeve; 521. Protruding ring; 522. Impact part; 6. Shear pin.

[0025] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0026] The invention will now be described with reference to the accompanying drawings.

[0027] In this application, it should be noted that the direction of the material being lowered into the well near the wellhead according to the present invention is described as "upstream," "upper end," or similar terms, i.e. Figure 1 The upper side is shown; the direction away from the wellhead is described as "downstream," "lower end," or similar terms, i.e. Figure 1 The lower side is shown.

[0028] Figure 1 The structure of the floating coupling 100 according to the present invention is shown. For example... Figure 1 As shown, the floating coupling 100 includes an outer cylinder 1, an upper connector 2, a lower connector 3, a fracturing element 4, and an impact assembly 5. The upper connector 2 and lower connector 3 are respectively sealed at the upper and lower ends of the outer cylinder 1. In this embodiment, the upper connector 2 and lower connector 3 are connected to the outer cylinder 1 via a threaded connection. It is easy to understand that both the upper connector 2 and lower connector 3 can connect to other downhole tubing. The fracturing element 4 and impact assembly 5 are both disposed inside the outer cylinder 1. The fracturing element 4 is sealed and fixed inside the outer cylinder 1, used to cooperate with other tubing connected to the floating coupling 100 to create a closed space. The impact assembly 5 is disposed below the fracturing element 4. Under a certain pressure, the impact assembly 5 can impact the fracturing element 4, breaking it and achieving full bore.

[0029] In one embodiment, the impact assembly 5 includes an inner sleeve 51 and an impact sleeve 52. The inner sleeve 51 is fixedly connected to the outer cylinder 1 and connected to the impact sleeve 52 via a shear pin 6. There are various ways to fix the inner sleeve 51 to the outer cylinder 1, such as via a pin connection, etc. Figure 4 As shown, sealing is required.

[0030] In this embodiment, the shear pin 6 only serves an initial fixing function, mainly preventing the impact sleeve 52 from accidentally colliding with the fractured part 4 during the handling and insertion of the floating coupling into the well. Therefore, the number of shear pins 6 required in this invention is small, and their strength is low. With this setup, there is no need for detailed design of the required strength of the shear pins 6, thereby reducing the difficulty of controlling the shear pins 6 during the design and production of the device. Furthermore, since only a small pressure difference is needed to shear the shear pins 6 during operation, the construction risk of the shear pins 6 failing to shear or the impact sleeve 52 failing to start under pressure operating conditions can be eliminated. Thus, without increasing the pumping pressure, the impact sleeve 52 can smoothly begin to move and collide with the fractured part 4 under the pressure at the moment of its explosion. This prevents excessive impact tonnage under high pumping pressure, which could lead to deformation or damage at the tip of the impact sleeve 52, reducing the strength requirements and control difficulty of the impact sleeve 52, and also reducing the pressure control difficulty during the pumping process.

[0031] According to the present invention, after the fractured component 4 explodes, the pressure above the fractured component 4 is transmitted to the impact sleeve 52. Therefore, even if the impact sleeve 52 does not completely remove the explosive residue of the fractured component 4 under the impact, the impact sleeve 52 will still generate a pressure differential force under the downhole fluid column pressure or circulating pressure in subsequent operations. Under the influence of the ever-present pressure differential force, the impact sleeve 52 crushes the residue of the fractured component 4. Since the residue is not intact, its compressive strength is greatly reduced under the impact crushing action of the impact sleeve 52. Thus, the residue can be crushed into fine particles through the crushing action, achieving full borehole.

[0032] In a preferred embodiment, the inner sleeve 51 is fixedly connected to the outer cylinder 1 by a snap-fit ​​connection. A C-ring 511 is provided on the outer wall of the inner sleeve 51, and a corresponding groove 512 is provided on the inner wall of the outer cylinder 1. In its natural state, the outer diameter of the C-ring 511 is larger than the outer diameter of the inner sleeve 51, and the inner diameter is smaller than the outer diameter of the inner sleeve 51. This design avoids directly installing shear pins on the cylinder wall of the outer cylinder 1, thereby enhancing the structural strength of the outer cylinder 1 and improving its sealing performance.

[0033] According to an embodiment of the present invention, the impact sleeve 52 includes a convex ring portion 521 and an impact portion 522. The wall thickness of the convex ring portion 521 is greater than that of the impact portion 522, and their inner diameters are equal. The convex ring portion 521 contacts the outer cylinder 1, and a sealing ring is provided between them. The impact portion 522 contacts the inner sleeve 51, and a sealing ring is also provided between them. A sealing ring is also provided between the inner sleeve 51 and the outer cylinder 1. With this arrangement, after the pumping pressure reaches the space where the impact sleeve 51 is located, the axial force of the impact sleeve 51 is applied to the lower end face of the convex ring portion 521 and the upper end face of the impact portion 522, respectively. Since the wall thickness of the convex ring portion 521 is greater than that of the impact portion 522, the area of ​​the lower end face of the convex ring portion 521 is greater than the area of ​​the upper end face of the impact portion 522. Under the pressure difference caused by the area difference at both ends, the impact sleeve 51 shears off the shear pin 6 and impacts the fractured part 4.

[0034] With this setup, the impact sleeve 52 has a small force-bearing area, and under the same pressure, the impact sleeve 52 experiences less pressure. Therefore, the number of shear pins 6 required is reduced, which lowers the design and control difficulty of the shear pins 6 during the design and production process of the device.

[0035] It is easy to understand that there is no sealed connection between the lower end of the impact sleeve 52 and the lower connector 3, so the pressure on the upper and lower ends of the impact sleeve 52 is equal. The force generated by the compression of air in the closed annular space formed between the impact sleeve 52, the outer cylinder 1, and the inner sleeve 51 is insufficient to affect the movement of the impact sleeve 52.

[0036] In one embodiment, the rupture element 4 is fixedly installed inside the outer cylinder 1 by abutting against other components. Specifically, a positioning protrusion 11 for installing the rupture element 4 is provided on the inner wall of the outer cylinder 1, and a positioning end face 111 is provided on the positioning protrusion 11. The rupture element 4 is sealed on the positioning protrusion 11, with one end abutting against the positioning end face 111 and the other end abutting against the upper connector 2.

[0037] To achieve the effect of sealing the tubing with the ruptured component 4, a sealing structure 41 can be installed on any of the three surfaces in contact with the ruptured component 4. The sealing structure 41 can be an O-ring on any of the aforementioned surfaces, such as an end face sealing ring between the upper connector 2 and the ruptured component 4, a radial sealing ring between the upper connector 2 and the outer cylinder 1, or an end face sealing ring between the upper connector 2 and the positioning end face 111. It can also be a semi-enclosed seal on two adjacent surfaces, or a fully enclosed seal on three surfaces.

[0038] Furthermore, to ensure that the fracture element 4 can withstand a certain pressure while also being shattered by the impact sleeve 52, the fracture element 4 is made of a high-pressure resistant, brittle non-metallic material, such as glass, ceramics, or resin. To improve the pressure resistance of the fracture element 4 at the same thickness, in addition to… Figure 1The cylinder shown can also be constructed as Figure 3 Other shapes, such as spherical shells, are shown.

[0039] In a preferred embodiment, a step 21 is provided on the lower inner wall of the upper connector 2, and the inner diameter of the step 21 is greater than or equal to the outer diameter of the impact sleeve 52. This arrangement ensures that the impact sleeve 52 breaks the fractured part 4 and then passes over it, thus achieving full bore.

[0040] The method of reducing the friction of the drilling fluid by sealing off a section of air or low-density drilling fluid with the fracture component 4 in this invention is the same as that in the prior art. The main difference is the way the fracture component 4 breaks after the pump pressure is applied in place, as detailed below.

[0041] Pressure is pumped into the space above the fractured component 4. After the fractured component 4 fractures, the impact assembly 5 begins to bear the pumped pressure, shearing off all the shear pins 6 and impacting the fractured component 4. The impact of the impact sleeve 52 causes a fractured through hole on the fractured component 4 that matches the contour of the impact sleeve 52, ultimately presenting... Figure 2 The effect shown achieves full bore.

[0042] According to the method of the crushing and breaking component 4 provided by the present invention, the floating coupling 100 provided by the present invention can achieve full bore, and the design strength of the shear pin 6 can be very small, thereby reducing the design difficulty of the shear pin 6 and improving the reliability of the device.

[0043] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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.

[0045] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention 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 invention should be included within the protection scope of the present invention.

Claims

1. A floating coupling, characterized in that, include: outer cylinder(1); The upper connector (2) is provided at the upper end of the outer cylinder; The lower connector (3) is provided at the lower end of the outer cylinder; A sealed and fixed fracture component (4) is provided inside the outer cylinder. A positioning protrusion (11) for installing the fracture component (4) is provided inside the outer cylinder (1). A positioning end face (111) is provided on the positioning protrusion (11). The lower end of the fracture component (4) abuts against the positioning end face, and the upper end of the fracture component abuts against the upper connector (2). And an impact assembly (5) disposed inside the outer cylinder, the impact assembly being disposed below the fracture member; Pressure is pumped into the space above the fractured part, causing the fractured part to rupture. The pressure above the fractured part is then transmitted to the impact assembly, which is configured to use the pressure difference between its upper and lower end faces to achieve displacement and impact on the fractured part under pressure.

2. The floating coupling according to claim 1, characterized in that, The impact assembly (5) includes an inner sleeve (51) that is sealed and fixedly connected to the outer cylinder (1) and an impact sleeve (52) that is fixed to the inner sleeve by a shear pin.

3. The floating coupling according to claim 2, characterized in that, A C-ring (511) is provided on the outer wall of the inner sleeve (51), and a groove (512) that mates with the C-ring is provided on the inner wall of the outer cylinder (1).

4. The floating coupling according to claim 3, characterized in that, The impact sleeve (52) includes a convex ring portion (521) and an impact portion (522). The wall thickness of the convex ring portion is greater than the wall thickness of the impact portion. The convex ring portion is sealed to the outer cylinder (1). The inner sleeve (51) is sealed between the impact portion and the outer cylinder (1).

5. The floating coupling according to claim 1, characterized in that, The upper end of the lower connector (3) extends into the interior of the outer cylinder (1) and abuts against the impact assembly (5).

6. The floating coupling according to claim 1, characterized in that, A step (21) is provided on the lower inner wall of the upper connector (2).

7. The floating coupling according to claim 1, characterized in that, A sealing structure (41) is provided on the ruptured component (4), and the sealing structure is a single-sided seal or a multi-sided seal.

8. The floating coupling according to claim 1, characterized in that, The fractured component (4) is made of a high-pressure resistant and fragile non-metallic material, which includes glass, ceramics, and resin.

9. The floating coupling according to claim 1, characterized in that, The fractured component (4) is cylindrical or spherical.

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