A floating coupling

Abstract

The present invention provides a floating coupling comprising a connecting pipe body, a blind plug installed within the connecting pipe body, and an impact assembly located above the blind plug. The impact assembly comprises a hydraulic sleeve with an impact portion, a hydraulic sleeve positioning member, and a bursting valve. The hydraulic sleeve and the connecting pipe body enclose two sealed cavities, and the sealing surfaces of the hydraulic sleeve located outside the two sealed cavities and the connecting pipe body have the same area. The bursting valve is disposed corresponding to the sealed cavity located above. The hydraulic sleeve positioning member shears when the bursting valve breaks through. The present invention has the advantages of simultaneously and precisely controlling the opening pressure of the floating coupling and the full diameter of the pipe, and is easy to operate and highly safe and reliable.

Description

Technical Field

[0001] The present invention relates to the field of oil drilling and completion, and in particular to a floating coupling. Background Art

[0002] When running casing in a horizontal well, the casing will descend closely against the bottom edge of the wellbore in the horizontal section. Furthermore, the drilling fluid injected into the casing during normal running increases the contact force between the casing and the wellbore wall, which in turn increases frictional resistance. This leads to problems such as high friction resistance and difficulty in running the casing. Especially as the length of horizontal well sections increases and the water-to-vertical ratio continues to increase, the weight of the casing in the diameter section is insufficient to push the casing downward, resulting in increasingly prominent problems such as resistance and inability to run the casing to the designed depth.

[0003] To address these issues, the current approach is to use floating casing running. The key tool for floating casing running is the floating coupling, which is connected to the middle of the pipe string to temporarily block the pipe. The lower horizontal section of the floating coupling is filled with air or a low-density fluid to reduce the positive pressure exerted by the horizontal section on the open hole wall, thereby reducing running friction. The key to the floating coupling is its ability to withstand the pressure of the liquid column in the upper tubing string and precisely open after the casing is lowered into place, ensuring full flow within the pipe and ensuring subsequent cementing operations.

[0004] Existing floating couplings mainly adopt two types: one is the sliding sleeve type, which is to open the floating coupling by inserting a specific rubber plug or other components to hold the pressure after the casing is lowered into place. At this time, the internal mechanism of the floating coupling needs to fall to the bottom of the casing, which is complicated to operate, and there is a risk of the sliding sleeve getting stuck, and the adaptability is not high. The other is the blind plate type, which uses fragile materials such as glass or ceramics to achieve temporary blocking in the pipe. After the casing is in place, the temporary blocking blind plate is crushed by holding the pressure in the pipe to open the floating coupling. However, since the blind plate needs to withstand the pressure of the upper liquid column and the agitation pressure, the pressure bearing capacity of the blind plate is high, and there may be a problem that it cannot be opened after holding the pressure. It cannot simultaneously ensure that the blind plate can withstand the pressure of the upper liquid column and the agitation pressure, and accurately control the opening function. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a floating coupling that can simultaneously achieve precise control of the opening pressure of the floating coupling and the full diameter in the pipe, and is easy to operate and has high safety and reliability.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0007] A floating coupling comprises a connecting pipe body, a sealing blind plate installed in the connecting pipe body, and an impact assembly located above the sealing blind plate, wherein the impact assembly comprises a hydraulic sleeve with an impact portion, a hydraulic sleeve positioning piece, and a bursting valve, wherein the hydraulic sleeve and the connecting pipe body enclose two sealed cavities, and the sealing surface area of ​​the hydraulic sleeve located outside the two sealed cavities is the same as that of the connecting pipe body; the bursting valve is arranged corresponding to the sealing cavity located on the upper side; and the hydraulic sleeve positioning piece is sheared off when the bursting valve is punctured.

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

[0009] A limiting sleeve supported on the connecting pipe body is provided in the sealing cavity located at the lower side, and the hydraulic sleeve positioning member is connected between the hydraulic sleeve and the limiting sleeve.

[0010] An upper limit platform and a lower limit platform are provided on the inner side of the connecting pipe body, and a limit groove which cooperates with the upper limit platform is provided on the upper end of the hydraulic sleeve; the limit sleeve is supported on the lower limit platform.

[0011] The length of the limiting groove along the axial direction of the connecting pipe body is greater than the downward movement distance of the hydraulic sleeve.

[0012] The connecting pipe body includes an upper joint, a connecting body and a lower joint. The upper joint and the lower joint are respectively connected to the inner sides of both ends of the connecting body. The lower end of the upper joint is the upper limit platform, and the upper end of the lower joint is the lower limit platform.

[0013] The floating coupling also includes a pressure ring pressed onto the upper end of the sealing blind plate. A blind plate limiting platform is provided on the inner side of the connecting pipe body. The sealing blind plate is axially limited by the pressure ring and the blind plate limiting platform.

[0014] The connecting pipe body is provided with a pressure relief channel for ensuring the downward movement of the hydraulic sleeve, and the pressure relief channel is communicated with the sealing cavity located at the lower side.

[0015] The impact portion is a plurality of impact heads with pointed ends, and the plurality of impact heads are arranged at intervals along the circumference of the bottom of the hydraulic sleeve.

[0016] The blocking blind plate is a tempered glass blind plate or a ceramic blind plate.

[0017] Sealing components for preventing leakage of high-pressure liquid are provided at the sealing surface positions of the hydraulic sleeve and the connecting pipe body, as well as between the blocking blind plate and the connecting pipe body.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] The floating coupling of the present invention includes a connecting pipe body, a blind plug, and an impact assembly. The blind plug is installed in the connecting pipe body, and the impact assembly is located above the blind plug. Its structure is simple and compact. The blind plug is designed to withstand the pressure of the liquid column in the upper pipe string, and the lower pipe string is sealed, with air or low-density drilling fluid inside, thereby enabling the floating lowering of the casing. At the same time, the impact assembly shatters the blind plug when the pressure at the wellhead reaches a certain level. Once the casing is lowered into place, it effectively opens the pipe string channel, achieving full bore in the pipe and ensuring smooth subsequent cementing operations.

[0020] The impact assembly includes a hydraulic sleeve with an impact portion, a hydraulic sleeve locating member, and a bursting valve. The hydraulic sleeve and the connecting pipe body enclose two sealed chambers. The hydraulic sleeve located outside the two sealed chambers has the same sealing surface area as the connecting pipe body. This ensures that during casing operation, regardless of changes in the internal pipe pressure, the hydraulic sleeve's ends are always in a state of pressure equilibrium, and the hydraulic sleeve locating member is not subjected to load, thereby effectively avoiding fatigue or premature shearing of the hydraulic sleeve locating member due to turbulent pressure, ensuring precise opening of the pipe string channel. It can simultaneously realize the function of the sealing blind plate to withstand the upper liquid column pressure and turbulent pressure, and the function of precisely controlling the opening of the sealing blind plate. The bursting valve is located in a corresponding position with the sealing chamber located on the upper side. When the casing is lowered into place, the bursting valve is pierced by the wellhead pressure, allowing high-pressure liquid to enter the sealing chamber corresponding to the bursting valve. At this time, the hydraulic sleeve locating member is sheared under the action of the high-pressure liquid, and the impact portion of the hydraulic sleeve quickly breaks the sealing blind plate, achieving full diameter in the pipe.

[0021] In addition, in deep, high-pressure wells, the liquid column pressure above the floating coupling often reaches over 50 MPa. With existing control methods, the liquid pressure generated by the inner diameter of the pipe when striking the blind plate acts entirely on the striking part. This enormous pressure may cause the striker to bend, deform, or damage, thereby affecting the inner diameter of the pipe and hindering the lowering of the subsequent operation string. The present invention, however, provides the downward impact force of the striking part through a sealed cavity. The effective area of ​​the sealed cavity is smaller than the cross-sectional area of ​​the inner pipe, effectively reducing the impact force of the striking part on the blind plate. At the same time, by setting the shear pressure of the hydraulic sleeve positioning member, the impact force is precisely controlled, thereby reducing the risk of damage to the striking part, ensuring the inner diameter of the pipe, and ensuring the reliable implementation of subsequent operations.

[0022] It can be seen that the present invention realizes precise control of the opening pressure of the floating coupling through the combined use of a hydraulic sleeve with balanced pressure at both ends, a hydraulic sleeve positioning member and a bursting valve, avoids the occurrence of premature opening of the blind plate, and ensures the full diameter of the pipe; at the same time, the present invention only needs to hold the pressure at the wellhead to a certain level to open the pipe to achieve the full diameter of the pipe, which is easy to operate and has high safety and reliability in on-site operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0024] Figure 1 Schematic diagram of the structure of the floating coupling of the present invention (initial state).

[0025] Figure 2 It is another structural schematic diagram of the floating coupling of the present invention (wellhead pressure holding state).

[0026] Figure 3 It is a structural diagram of the hydraulic sleeve.

[0027] The numbers in the figure represent:

[0028] 1. Connecting pipe body; 11. Upper limit platform; 12. Lower limit platform; 13. Upper joint; 14. Connecting body; 15. Lower joint; 16. Blind plate limit platform; 17. Pressure relief channel; 2. Blocking blind plate; 3. Impact assembly; 31. Hydraulic sleeve; 331. Impact part; 3311. Impact head; 332. Limit groove; 32. Hydraulic sleeve positioning part; 33. Burst valve; 4. Sealing chamber; 5. Sealing surface; 6. Limit sleeve; 7. Pressure ring; 8. Sealing component. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereby.

[0030] like Figure 1 and Figure 2 The embodiment of the floating coupling of the present invention is shown. The floating coupling is mainly used in horizontal wells with long horizontal sections. The floating coupling includes a connecting pipe body 1, a blocking blind plate 2 and an impact assembly 3. Among them, the connecting pipe body 1 is connected to the middle of the casing string. The blocking blind plate 2 is installed in the connecting pipe body 1. The setting of the blocking blind plate 2 can withstand the pressure of the liquid column in the upper pipe string to achieve temporary blocking in the pipe; and the lower pipe string is in a sealed state, and its interior is air or low-density drilling fluid, which reduces the positive pressure of the horizontal section casing on the open hole wall, thereby reducing the friction resistance of the lowering and achieving the floating lowering of the casing. The impact assembly 3 is located above the blocking blind plate 2. When the pressure at the wellhead reaches a certain pressure, the impact assembly 3 smashes the blocking blind plate 2. After the casing is lowered into place, it can effectively open the pipe string channel to achieve full diameter in the pipe, ensuring the smooth progress of subsequent cementing operations. It has a simple and compact structure.

[0031] In this embodiment, the impact assembly 3 includes a hydraulic sleeve 31 with an impact portion 331, a hydraulic sleeve locating member 32, and a burst valve 33. The hydraulic sleeve 31 and the connecting pipe body 1 enclose two sealed cavities 4. The sealing surface 5 of the hydraulic sleeve 31 located outside the two sealed cavities 4 and the connecting pipe body 1 has the same area. This ensures that regardless of changes in the internal pipe pressure, the pressure across the hydraulic sleeve 31 remains balanced during casing lowering. The hydraulic sleeve locating member 32 is not subjected to any load, effectively preventing fatigue or premature shearing of the hydraulic sleeve locating member 32 due to turbulent pressure. This ensures precise opening of the pipe string passageway, simultaneously ensuring that the blind plate 2 withstands both the upper liquid column pressure and the turbulent pressure, and precisely controlling the opening of the blind plate 2.

[0032] At the same time, a bursting valve 33 is provided on the hydraulic sleeve 31, and the bursting valve 33 is provided corresponding to the sealed cavity 4 located on the upper side; a hydraulic sleeve positioning member 32 is provided between the hydraulic sleeve 31 and the connecting pipe body 1, and the hydraulic sleeve positioning member 32 is sheared off when the bursting valve 33 is penetrated. When the casing is lowered into place, the bursting valve 33 is penetrated by the wellhead pressure, and the bursting valve 33 connects the interior of the connecting pipe body 1 with the sealed cavity 4 located on the upper side, allowing high-pressure liquid to enter the sealed cavity 4 corresponding to the bursting valve 33. At this time, the hydraulic sleeve positioning member 32 is sheared off under the action of the high-pressure liquid pressure, and the impact part 331 of the hydraulic sleeve 31 quickly smashes the blocking blind plate 2, achieving full diameter in the pipe.

[0033] In addition, in deep, high-pressure wells, the liquid column pressure above the floating coupling often reaches over 50 MPa. With existing control methods, the liquid pressure generated by the inner diameter of the pipe when striking the blind plate acts entirely on the striking part. This enormous pressure may cause the striker to bend, deform, or damage, thereby affecting the inner diameter of the pipe and hindering the lowering of the subsequent operation string. The present invention, however, provides the downward impact force of the striking part through a sealed cavity. The effective area of ​​the sealed cavity is smaller than the cross-sectional area of ​​the inner pipe, effectively reducing the impact force of the striking part on the blind plate. At the same time, by setting the shear pressure of the hydraulic sleeve positioning member, the impact force is precisely controlled, thereby reducing the risk of damage to the striking part, ensuring the inner diameter of the pipe, and ensuring the reliable implementation of subsequent operations.

[0034] It can be seen that the present invention realizes precise control of the opening pressure of the floating coupling through the combined use of a hydraulic sleeve with balanced pressure at both ends, a hydraulic sleeve positioning member and a bursting valve, avoids the occurrence of premature opening of the blind plate, and ensures the full diameter of the pipe; at the same time, the present invention only needs to hold the pressure at the wellhead to a certain level to open the pipe to achieve the full diameter of the pipe, which is easy to operate and has high safety and reliability in on-site operations.

[0035] Furthermore, a limiting sleeve 6 is provided within the lower sealed chamber 4. The limiting sleeve 6 is supported on the connecting tube body 1, and the hydraulic sleeve positioning member 32 is connected between the hydraulic sleeve 31 and the limiting sleeve 6. This ensures that the hydraulic sleeve 31 is securely fixed in place by the hydraulic sleeve positioning member 32 and the limiting sleeve 6, preventing the hydraulic sleeve 31 from moving downward. This structure is simple and does not require additional space. In this embodiment, the hydraulic sleeve positioning member 32 is a shear pin, and the limiting sleeve 6 is a shear pin sleeve.

[0036] Furthermore, the inner side of the connecting tube body 1 is provided with an upper limit platform 11 and a lower limit platform 12. The upper end of the hydraulic sleeve 31 is provided with a limit groove 332, which cooperates with the upper limit platform 11 for limiting position. The limit sleeve 6 is supported on the lower limit platform 12, which further ensures the reliable limit installation of the hydraulic sleeve 31.

[0037] like Figure 2 As shown, the length of the limiting groove 332 along the axial direction of the connecting pipe body 1 is greater than the downward movement distance of the hydraulic sleeve 31. This ensures that after the hydraulic sleeve 31 moves downward and the impact portion 331 breaks the blocking blind plate 2, the upper end of the limiting groove 332 of the hydraulic sleeve 31 overlaps the inner surface of the upper limit platform 11, allowing the subsequent operation string to pass through this position smoothly, avoiding the occurrence of obstruction in the pipe. At the same time, during subsequent operations, impurities can be effectively prevented from entering the gap between the connecting pipe body 1 and the hydraulic sleeve 31, ensuring the reliable and safe operation of subsequent operations.

[0038] like Figure 1 and Figure 2 As shown, the connecting pipe body 1 includes an upper joint 13, a connecting body 14 and a lower joint 15. The upper joint 13 and the lower joint 15 are respectively connected to the inner sides of the two ends of the connecting body 14, the lower end of the upper joint 13 is the upper limit platform 11, and the upper end of the lower joint 15 is the lower limit platform 12.

[0039] like Figure 3 As shown, the impact part 331 is a plurality of impact heads 3311 with pointed ends, and the plurality of impact heads 3311 are evenly spaced along the circumference of the bottom of the hydraulic sleeve 31 to apply a point impact load to the blocking blind plate 2 to ensure that the impact part 331 has a crushing effect on the blocking blind plate 2.

[0040] Preferably, the blind plug 2 is made of tempered glass or ceramic, and is composed of one or more layers. Its surface strength is reliably above 350 MPa, and a single layer of blind plug 2 can withstand high pressure differentials exceeding 50 MPa. It can be crushed into fine particles under a certain pressure, allowing it to be circulated with the drilling fluid without affecting subsequent operations.

[0041] Furthermore, a sealing component 8 is provided at the sealing surface 5 of the hydraulic sleeve 31 and the connecting pipe body 1 to effectively prevent leakage of the high-pressure liquid. In this embodiment, the sealing component 8 is a sealing ring.

[0042] In this embodiment, the floating coupling also includes a compression ring 7, which is pressed against the upper end of the blind plate 2. A blind plate stopper 16 is provided on the inner side of the connecting pipe body 1. The blind plate 2 is axially restrained by the compression ring 7 and the stopper 16 to prevent movement during installation and ensure reliable operation. Furthermore, after the impact portion 331 shatters the blind plate 2, the hydraulic sleeve 31 engages the compression ring 7 in axial restraint, securing the hydraulic sleeve 31 in its axial position.

[0043] Furthermore, the connecting pipe body 1 is provided with a pressure relief channel 17, which is connected to the sealed chamber 4 located below. This pressure relief channel 17 is used to relieve the pressure in the sealed chamber 4 below when the hydraulic sleeve 31 descends, ensuring smooth downward movement of the hydraulic sleeve 31. At the same time, the impact from top to bottom on the blind plate 2 is consistent with the crushing direction of the blind plate 2, which is more conducive to crushing and achieving full diameter.

[0044] While the present invention has been described with reference to preferred embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A floating coupling, characterized in that: The cam is secured to the upper edge of the cam and secured to the lower edge of the cam, and the cam is secured to the lower edge of the cam, the cam being secured to the cam by a force, so that the cam is in a position to move relative to the piston rod and thereby prevent the piston from sliding off the cam. The sealing chamber on the side is correspondingly arranged; the hydraulic sleeve positioning piece is arranged between the hydraulic sleeve and the connecting pipe body, and the hydraulic sleeve positioning piece is sheared off when the bursting valve is punctured. When the casing is lowered into place, the bursting valve is punctured by the wellhead pressure, and the bursting valve connects the interior of the connecting pipe body with the sealing chamber located on the upper side, so that high-pressure liquid enters the sealing chamber corresponding to the bursting valve, and the hydraulic sleeve positioning piece is sheared off under the action of the high-pressure liquid pressure, and the impact part of the hydraulic sleeve quickly smashes the blocking blind plate to achieve full diameter in the pipe; the inner side of the connecting pipe body is provided with an upper limit platform and a lower limit platform, and the upper end of the hydraulic sleeve is provided with a limiting groove that cooperates with the upper limit platform; the limit sleeve is supported on the lower limit platform; the connecting pipe body is provided with a pressure relief channel to ensure the downward movement of the hydraulic sleeve, and the pressure relief channel is connected to the sealing chamber located on the lower side.

2. The floating collar according to claim 1, characterized in that: The length of the limiting groove along the axial direction of the connecting pipe body is greater than the downward movement distance of the hydraulic sleeve.

3. The floating collar according to claim 1, characterized in that: The connecting pipe body includes an upper joint, a connecting body and a lower joint. The upper joint and the lower joint are respectively connected to the inner sides of both ends of the connecting body. The lower end of the upper joint is the upper limit platform, and the upper end of the lower joint is the lower limit platform.

4. The floating coupling according to any one of claims 1 to 3, characterized in that: The impact portion is a plurality of impact heads with pointed ends, and the plurality of impact heads are arranged at intervals along the circumference of the bottom of the hydraulic sleeve.

5. The floating coupling according to any one of claims 1 to 3, characterized in that: The blocking blind plate is a tempered glass blind plate or a ceramic blind plate.

6. The floating coupling according to any one of claims 1 to 3, characterized in that: Sealing components for preventing leakage of high-pressure liquid are provided at the sealing surface positions of the hydraulic sleeve and the connecting pipe body, as well as between the blocking blind plate and the connecting pipe body.

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