A floating collar

Abstract

The application provides a floating collar, which comprises an upper joint, a lower joint arranged at the lower end of the assembling part, a sealing fixed sleeve of a plugging assembly arranged in the assembling part, and a first shear pin sleeve of a shear pin arranged in the assembling part, wherein the upper joint comprises a joint part and an assembling part, and the inner diameter of the assembling part is smaller than that of the joint part; the first shear pin sleeve is arranged above the plugging assembly, and the area of the upper end pressure surface of the first shear pin sleeve is larger than that of the lower end pressure surface, so that the first shear pin sleeve can cut the shear pin under the action of pressure and hit the plugging assembly. The application can realize the full gauge of the pipe string after the rupture disc is broken, can 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 fracturing disc floating coupling. This type of coupling seals a section of air or low-density drilling fluid through a fracturing disc. After the tubing string is in place, the fracturing disc is broken by direct pressure buildup. However, the pressure buildup method may result in incomplete fracturing of the disc, meaning the tubing string may not reach full bore. Incomplete fracturing of the disc can affect the passage performance of cement plugs during subsequent operations. When the cement plug passes through, it may be damaged by the remaining fracturing disc, 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, severely affecting cementing quality, and even causing the cement plug to fail due to pressure contact or 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 disc exists in the existing technology. This type of floating coupling has a movable fracture disc and a fixed first shear pin sleeve. The fracture disc is positioned above the first shear pin sleeve, and the first shear pin sleeve is fixed to the fracture disc by shear pins. When it is necessary to fracture the fracture disc, pressure is pumped from above the fracture disc, pushing the fracture disc to shear the shear pins and then impact the first shear pin sleeve, thereby completely fracturing the fracture disc. Although this technology can achieve full-bore tubing, it is necessary to ensure that the fracture disc 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 disc and ensure that the fracture disc works normally during the running-in process. 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 mud in the well, resulting in premature shearing and process failure, and causing the tubing to fail to run into place smoothly. The use of multiple shear pins results in extremely high pumping pressure during the crushing of the rupture disc. Since the rupture disc bears the pressure to shear the shear pins, such pumping pressure may cause the rupture disc to break prematurely. If the rupture disc breaks before the shear pins break due to unforeseen circumstances or if the seal fails, the shear pins will not be able to cut, preventing the rupture disc from hitting the first shear pin sleeve. This makes it impossible to achieve full bore of the tubing and seriously affects subsequent construction operations. 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 upper connector, the upper connector including a connector portion and an assembly portion, the inner diameter of the assembly portion being larger than the inner diameter of the connector portion; a lower connector disposed at the lower end of the assembly portion; a sealing assembly fixedly sleeved within the assembly portion; and a first shear pin sleeve and a second shear pin sleeve disposed within the assembly portion by shear pins; wherein the first shear pin sleeve and the second shear pin sleeve are respectively disposed above and below the sealing assembly, and the area of ​​the pressure-bearing surface of the first shear pin sleeve and the second shear pin sleeve away from the sealing assembly is larger than the area of ​​the pressure-bearing surface near the sealing assembly, thereby enabling the first shear pin sleeve to shear the shear pin under pressure and impact the sealing assembly.

[0008] In one embodiment, the upper portion of the lower connector extends into the assembly portion and abuts against the sealing assembly.

[0009] In one embodiment, a connecting cylinder is sleeved between the first shear pin sleeve and the assembly part, and the upper and lower ends of the connecting cylinder abut against the joint part and the sealing assembly, respectively. The first shear pin sleeve is fixedly connected to the connecting cylinder by a shear pin.

[0010] In one embodiment, the first clipper sleeve includes a first fitting portion and a second fitting portion, wherein the outer diameter of the first fitting portion is larger than the outer diameter of the second fitting portion, and the inner diameter of the first fitting portion is equal to the inner diameter of the second fitting portion; the connecting cylinder includes a third fitting portion and a fourth fitting portion, wherein the inner diameter of the third fitting portion is larger than the inner diameter of the fourth fitting portion; a sealing element is provided between the first fitting portion and the third fitting portion, and a sealing element is provided between the second fitting portion and the fourth fitting portion.

[0011] In one embodiment, the sealing assembly includes a base and a rupture disc fixedly disposed on the base, the rupture disc being capable of sealing the base.

[0012] In one embodiment, the base includes a fifth fitting portion and a sixth fitting portion disposed at the lower end of the fifth fitting portion. The inner diameter of the fifth fitting portion is smaller than the inner diameter of the sixth fitting portion. The second shear pin sleeve includes a seventh fitting portion and an eighth fitting portion disposed at the lower end of the seventh fitting portion. The outer diameter of the seventh fitting portion is smaller than the outer diameter of the eighth fitting portion. The inner diameter of the seventh fitting portion is equal to the inner diameter of the eighth fitting portion. The seventh fitting portion is sealed within the fifth fitting portion, and the eighth fitting portion is sealed within the sixth fitting portion. The eighth fitting portion and the sixth fitting portion are fixedly connected by shear pins.

[0013] In one embodiment, a first step is provided on the inner wall of the fifth assembly, and the rupture disc is disposed on the first step, with both ends of the rupture disc abutting against the stepped surface of the first step and the fourth assembly, respectively.

[0014] In one embodiment, an end face sealing ring is provided between the rupture disc and the fourth fitting portion.

[0015] In one embodiment, the outer diameter of the second fitting is equal to the outer diameter of the seventh fitting.

[0016] In one embodiment, the shear pin connecting the first shear pin sleeve and the assembly part is a soluble pin.

[0017] In one embodiment, the rupture disc is made of a high-pressure resistant, fragile non-metallic material, including glass and ceramic, and the rupture disc is cylindrical or spherical.

[0018] Compared with the prior art, this application has the following advantages.

[0019] This invention isolates the drilling mud by using a fracturing disc during tubing string insertion and seals a section of air or low-density drilling fluid between the floating coupling and the tubing string. Buoyancy reduces the weight of the tubing string entering the inclined or horizontal section of the well, thereby reducing friction and facilitating smooth insertion. In this invention, the fracturing disc is fixedly mounted within the assembly section, and the first and second shear pin sleeves are only connected within the assembly section via a small number of shear pins, reducing the difficulty of pin design and control. During the fracturing disc fracturing process, the first shear pin sleeve uses the pressure difference between its upper and lower ends to displace, shearing the shear pins and impacting the fracturing disc. Then, the second shear pin sleeve uses the pressure difference between its upper and lower ends to displace, further fracturing the disc, improving the reliability of the invention. Finally, the fragments from the fracturing disc are carried out through circulation. With this setup, even if the fracturing disc fails prematurely, the first shear pin sleeve can still displace under pressure and impact the disc. This invention achieves full-bore tubing after the fracturing disc is broken, reduces construction risks, and features a simple structure and convenient construction. Attached Figure Description

[0020] The present invention will now be described with reference to the accompanying drawings.

[0021] Figure 1 A schematic diagram of the initial state of an embodiment of the floating coupling according to the present invention is shown;

[0022] Figure 2 This shows a schematic diagram of a rupture disc after it has broken, according to an embodiment of the floating coupling of the present invention;

[0023] Figure 3 A schematic diagram of another embodiment of the crushing disc according to the present invention is shown.

[0024] In the diagram: 1. Upper connector; 11. Connector section; 12. Assembly section; 2. Sealing assembly; 21. Base; 22. Rupture disc; 23. Fifth fitting section; 231. First step; 24. Sixth fitting section; 31. First shear pin sleeve; 311. First fitting section; 312. Second fitting section; 32. Connecting cylinder; 321. Third fitting section; 322. Fourth fitting section; 33. Second shear pin sleeve; 331. Seventh fitting section; 332. Eighth fitting section; 34. First shear pin; 35. Second shear pin; 4. Lower connector; 5. End face sealing ring.

[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 left side shown; the direction away from the wellhead is described as "downstream," "lower end," or similar terms, i.e. Figure 1 The right side is shown.

[0028] Figure 1 The structure of the floating coupling 100 according to the present invention is shown. (See figure) Figure 1 As shown, the floating coupling 100 includes an upper connector 1, a lower connector 4, a plugging assembly 2, a second shear pin sleeve 33, and a first shear pin sleeve 31. The upper connector 1 includes a connector portion 11 and an assembly portion 12 disposed at the lower end of the connector portion 11, the inner diameter of the assembly portion 12 being larger than the inner diameter of the connector portion 11. The lower connector 4 is sealed and disposed at the lower end of the assembly portion 12 via a threaded connection. It is easy to understand that both the upper connector 1 and the lower connector 4 can be connected to other downhole tubing. The plugging assembly 2, the second shear pin sleeve 33, and the first shear pin sleeve 31 are all disposed within the assembly portion 12. Specifically, the plugging assembly 2 is sealed and fixedly disposed within the assembly portion 12, the first shear pin sleeve 31 is fixedly disposed within the assembly portion via a first shear pin 34, located above the plugging assembly 2, and the second shear pin sleeve 33 is fixedly disposed within the assembly portion via a second shear pin 35, located below the plugging assembly 2. Furthermore, the upper pressure-bearing area of ​​the first shear pin sleeve 31 is greater than that of the lower pressure-bearing area, and the lower pressure-bearing area of ​​the second shear pin sleeve 33 is greater than that of the upper pressure-bearing area. When full bore is required for the tubing string, pressure is pumped into the floating coupling 100 from the wellhead direction. Under the same pressure, when the pressure difference between the upper and lower pressure-bearing surfaces of the first shear pin sleeve 31 exceeds the rated shear force of the first shear pin 34, the first shear pin 34 is sheared, and the first shear pin sleeve 31 will then collide with the sealing assembly 2, thereby breaking the sealing assembly 2. After the sealing assembly 2 breaks, the area where the second shear pin sleeve 33 is located is filled with pressure. When the pressure difference between its upper and lower pressure-bearing surfaces exceeds the rated shear force of the second shear pin 35, the second shear pin 35 is sheared, and the second shear pin sleeve 33 will then collide with the sealing assembly 2, causing secondary breakage of the sealing assembly. Full bore is achieved through two stages of breaking the sealing assembly 2, improving the reliability of the invention.

[0029] In this configuration, since the sealing assembly 2 no longer controls the cutting of the first shear pin 34, even if the sealing assembly 2 fails, it will not affect the impact of the first shear pin sleeve 31 and the second shear pin sleeve 33 against the sealing assembly 2 under pressure. Furthermore, the axial force-bearing areas of the first shear pin sleeve 31 and the second shear pin sleeve 33 are small. Under the same pressure, the pressure on the first shear pin sleeve 31 is less, thus requiring fewer shear pins and reducing the difficulty of controlling the shear pins during the design and production of the device. Simultaneously, this invention also reduces the difficulty of pressure control during the pumping process.

[0030] According to a preferred embodiment of the present invention, a connecting cylinder 32 is sleeved between the first shear pin sleeve 31 and the assembly part 12. The upper end of the connecting cylinder 32 abuts against the joint part 11, and the lower end abuts against the sealing component 2. The first shear pin sleeve 31 is fixedly connected to the connecting cylinder 32 by a first shear pin 34. With this arrangement, on the one hand, the purpose of fixing the first shear pin sleeve 31 and the assembly part 12 to the assembly part 12 by the shear pin can be achieved; on the other hand, it avoids directly installing the shear pin on the assembly part 12, thereby enhancing the overall strength and sealing performance of the assembly part 12. During the use of the device, the connecting cylinder 32 and the base 21 will be subjected to axial forces, such as forces due to the pressure difference of their own end faces. Therefore, the two ends of the connecting cylinder 32 and the base 21 can be more firmly and reliably fixed by abutting against other components.

[0031] In one specific embodiment, the first shearing sleeve 31 includes a first fitting portion 311 and a second fitting portion 312 disposed at the lower end of the first fitting portion 311. The outer diameter of the first fitting portion 311 is larger than the outer diameter of the second fitting portion 312, and the inner diameter of the first fitting portion 311 is equal to the inner diameter of the second fitting portion 312. The connecting cylinder 32 includes a third fitting portion 321 and a fourth fitting portion 322 disposed at the lower end of the third fitting portion 321. The inner diameter of the third fitting portion 321 is larger than the inner diameter of the fourth fitting portion 322. A sealing element is provided between the first fitting portion 311 and the third fitting portion 321, and a sealing element is provided between the second fitting portion 312 and the fourth fitting portion 322. In this configuration, the upper pressure surface of the first shear pin sleeve 31 is the upper end surface of the first fitting part 311, and the lower pressure surface of the first shear pin sleeve 31 is the lower end surface of the second fitting part 312. Under the same pressure, the axial pressure on the upper end surface of the first fitting part 311 is greater than the axial pressure on the lower end surface of the second fitting part 312, thereby achieving the purpose of the first shear pin sleeve 31 cutting off the first shear pin 34 and impacting the sealing component 2 under the action of the pumping pressure.

[0032] It is easy to understand that there is no sealed connection between the upper end face of the first shear pin sleeve 31 and the connector portion 11, therefore the pressure on the upper and lower end faces of the first shear pin sleeve 31 is equal. The force generated by the compression of air in the closed annular space formed between the first shear pin sleeve 31 and the connecting cylinder 32 is insufficient to affect the movement of the first shear pin sleeve 31.

[0033] In one specific embodiment, the sealing component 2 is fixedly installed within the assembly section 12 by abutting against other components. Specifically, the upper part of the lower connector 4 extends into the assembly section 12 and abuts against the lower end of the sealing component 2. In conjunction with the above embodiment, the upper end of the sealing component 2 abuts against the connecting cylinder 32. This completes the fixing of the sealing component 2.

[0034] In a preferred embodiment, the sealing assembly 2 includes a base 21 and a rupture disc 22 fixedly mounted on the base. The axial length of the base 21 is greater than the axial length of the rupture disc 22, thereby facilitating the installation of the sealing assembly 2 into the upper connector 1. Furthermore, to ensure that the rupture disc 22 can withstand a certain pressure and be broken by the first shear pin sleeve 31 and the second shear pin sleeve 33, the rupture disc is made of a high-pressure resistant, brittle non-metallic material, such as glass or ceramic. Additionally, to improve the pressure resistance of the rupture disc 22 at the same thickness, the rupture disc 22, besides… Figure 1 The cylinder shown can also be constructed as Figure 3 Other shapes, such as spherical shells, are shown.

[0035] In one specific embodiment, the base 21 includes a fifth fitting portion 23 and a sixth fitting portion 24 disposed at the lower end of the fifth fitting portion 23. The inner diameter of the fifth fitting portion 23 is smaller than the inner diameter of the sixth fitting portion 24. The second shear pin sleeve 33 includes a seventh fitting portion 331 and an eighth fitting portion disposed at the lower end of the seventh fitting portion 332. The outer diameter of the seventh fitting portion 331 is smaller than the outer diameter of the eighth fitting portion 332, and the inner diameter of the seventh fitting portion 331 is equal to the inner diameter of the eighth fitting portion 332. The seventh fitting portion 331 is sealed inside the fifth fitting portion 23, and the eighth fitting portion 332 is sealed inside the sixth fitting portion 24. The eighth fitting portion 332 and the sixth fitting portion 24 are fixedly connected by a second shear pin 35. In this configuration, the upper pressure surface of the second shear pin sleeve 33 is the upper end surface of the seventh assembly 331, and the lower pressure surface of the second shear pin sleeve 33 is the lower end surface of the eighth assembly 332. Under the same pressure, the axial pressure on the upper end surface of the seventh assembly 331 is greater than the axial pressure on the lower end surface of the eighth assembly 332, thereby achieving the purpose of the second shear pin sleeve 33 cutting off the second shear pin 35 and impacting the sealing assembly 2 under the action of the pumping pressure.

[0036] In one specific embodiment, a first step 231 is provided on the inner wall of the fifth fitting part 23, and a rupture disc 22 is disposed on the first step 231. The diameter of the cylindrical surface of the first step 231, i.e., the diameter of the rupture disc, is larger than the inner diameter of the connecting cylinder 32, so that the upper end of the rupture disc 22 can abut against the connecting cylinder 32, and the right end of the rupture disc 22 abuts against the end face of the first step 231. Simultaneously, to achieve a sealing effect, a sealing ring can be provided between the rupture disc 22 and the contact surfaces of the first step 231 and / or the connecting cylinder 32. In this embodiment, a sealing groove is provided on the lower end face of the connecting cylinder 32, and an end face sealing ring 5 is provided in the sealing groove. Providing an end face sealing ring 5 between the rupture disc 22 and the connecting cylinder 32 is more convenient than installing a sealing ring on the step surface of the first step 221, which would result in an increase in the overall outer diameter. Figure 1The sealing ring installation method shown can obtain a wider shoulder support, protect the weak edge of the rupture disc 22, and also obtain a thicker impact sleeve 31 with greater impact strength. This makes the floating coupling of the present invention not only have the full bore of the entire pipe, but also have a smaller tool outer diameter on the entire pipe, which facilitates the lowering of the pipe.

[0037] like Figure 1 As shown, in conjunction with the above embodiments, the assembly process of the floating coupling 100 is as follows: First, install the sealing rings in the sealing grooves of the first shear pin sleeve 31 and the connecting cylinder 32 respectively, and then assemble the first shear pin sleeve 31 according to... Figure 1 The position shown is fitted inside the connecting cylinder 32, and the first shear pin 34 is inserted from the outside of the connecting cylinder 32, thereby fixing the first shear pin sleeve 31 to the connecting cylinder 32. Then, the end face sealing ring 5 is installed in the sealing groove of the connecting cylinder 32, completing the assembly of the first part; then, the sealing ring is installed in the sealing groove of the inner wall of the base 21 and the outer wall of the second shear pin sleeve 33, and the second shear pin sleeve 33 is fitted inside the base 21. The second shear pin 35 is inserted from the outside of the base 21, thereby fixing the second shear pin sleeve 33 and the base 21. Then, the rupture disc 22 is installed on the first step 231, and at the same time, a sealing ring for sealing with the assembly part is installed on the outer wall of the base 21 through the sealing groove, completing the installation of the second part; finally, according to Figure 1 Following the direction shown, insert the first and second parts, now installed, sequentially from the lower end of the upper connector 1, and then install the lower connector 4, with the sealing ring installed, at the lower end of the upper connector 1. The sealing rings and sealing methods mentioned above include skeleton sealing rings, O-rings, etc.

[0038] According to a specific embodiment of the present invention, the outer diameter of the second fitting portion 312 is equal to the outer diameter of the seventh fitting portion 23. This arrangement allows the first shear pin sleeve 31 and the second shear pin sleeve 33 to impact the same location on the rupture disc 22.

[0039] This invention can achieve multiple usage methods by controlling the strength of the first shear pin 34 and the second shear pin 35. The usage method of reducing the running friction by sealing a section of air or low-density drilling fluid with the fracture disc 22 is the same as the prior art. The main difference is the crushing method of the fracture disc 22 after it is pumped into place, as detailed below.

[0040] Method 1: When the strength of the first shear pin 34 and the second shear pin 35 is relatively low, i.e. after pumping pressure, the first shear pin sleeve 31 tends to move downward under pressure, and the first shear pin 34 is sheared by the first shear pin sleeve 31. Subsequently, the first shear pin sleeve 31 impacts the rupture disc 22, and the impact of the first shear pin sleeve 31 creates a weak point on the rupture disc 22 that matches the contour of the first shear pin sleeve 31. After increasing the pumping pressure, the rupture disc 22 bursts into fine particles along the contour formed by the weak point under pressure. After the rupture disc 22 ruptures, the second shear pin sleeve 33 begins to be pushed by pressure. At this time, the pressure is greater than the pressure when the first shear pin 34 breaks. Therefore, under the premise that the pressure-bearing area is the same as that of the first shear pin sleeve 31, the second shear pin sleeve 33 will generate a greater acceleration to impact the rupture disc 22, performing secondary crushing of the rupture disc 22, ensuring that the tubing achieves full bore, and ultimately presents... Figure 2 The effect is shown. The debris from the breaker disc 22 is then carried out through a circulation process. In this method, even if the breaker disc 22 fails prematurely due to bursting before the first shear pin 34 breaks, the two bursts of the first shear pin sleeve 31 and the second shear pin sleeve 33 are sufficient to achieve full bore. With this setup, the strength of the second shear pin 35 only needs to ensure that the second shear pin sleeve 33 can be stably installed within the floating coupling during transport and well insertion, thus reducing the design complexity of the invention. In this embodiment, the pumping pressure will not exceed the bursting pressure of the breaker disc 22, ensuring that the shear pin can break normally under low pumping pressure.

[0041] Method Two: When the strength of the first shear pin 34 is greater than that of Method One, i.e. after the pumping pressure, the first shear pin sleeve 31 tends to move downward under pressure, and the first shear pin 34 is sheared by the first shear pin sleeve 31. Subsequently, the first shear pin sleeve 31 impacts the rupture disc 22. The impact of the first shear pin sleeve 31 causes a through hole on the rupture disc 22 that matches the contour of the first shear pin sleeve 31. The part that detaches from the rupture disc 22 is instantly broken into fine particles. Similar to Method One, after the rupture disc 22 is broken, the second shear pin sleeve 33 performs secondary crushing on the rupture disc 22, ultimately presenting... Figure 2 The effect shown achieves full bore. In this method, even if the fracture disc 22 fails prematurely due to explosion before the shear pin 34 breaks—for example, if the fracture disc 22 breaks due to an unexpected situation under a pumping pressure lower than its rated strength—it will not affect the achievement of full bore. The strength of the second shear pin 35 only needs to ensure that the second shear pin sleeve 33 can be stably installed inside the floating coupling during transportation and well insertion, thereby reducing the design difficulty of the invention. In this embodiment, the pumping pressure will not exceed the explosion pressure of the fracture disc 22, ensuring that the shear pin can break normally under low pumping pressure.

[0042] Method 3: When the strength of the first shear pin 34 is greater than that of Method 2, i.e., after pumping pressure, the first shear pin sleeve 31 tends to move downward under pressure. However, the rupture disc 22 ruptures before the first shear pin 34, i.e., the main body explodes into fine particles. Then, the first shear pin 34 and the second shear pin 35 are sheared off respectively. Subsequently, the first shear pin sleeve 31 and the second shear pin sleeve 33 collide with the rupture disc 22, cleaning up the remaining parts at the edge of the rupture disc 22 to achieve full bore. In a specific embodiment, the first shear pin 34 is a soluble pin made of high-strength soluble material. Before installation, a solid flux is first introduced into the pin hole to partially fill the soluble pin, and then the soluble pin is installed into the pin hole. Correspondingly, after the floating coupling is lowered, during the grouting process, a section of isolation fluid needs to be pumped into the floating coupling section first, and then mud is pumped in. The mud is isolated from the solid co-solvent and soluble pins by an isolation fluid, preventing the solid co-solvent from causing the soluble pins to dissolve prematurely when immersed in the mud. The strength of the second shear pin 35 only needs to ensure that the second shear pin sleeve 33 can be stably installed inside the floating coupling during transportation and well insertion, thereby reducing the design difficulty of the invention. In this embodiment, the pumping pressure does not need to exceed the bursting pressure of the fractured plate 22, thereby effectively preventing the mud from being squeezed into the formation due to excessive pumping pressure, thus reducing the formation oil and gas production. The specific working principle of this embodiment is as follows.

[0043] After the pump pressure is applied, the fractured disc 22 ruptures before the soluble pin (i.e., the first shear pin 34). Following the rupture of the fractured disc 22, the floating coupling section containing the second shear pin 35 is pressurized, causing the second shear pin 35 to be sheared off. The second shear pin sleeve 33 then impacts the fractured disc 22, clearing away the remaining debris. Simultaneously, the pre-pumped isolation fluid is replaced by the drilling mud above, flowing down the tubing string and rendering the isolation fluid ineffective. This means the isolation fluid loses its protective function against the solid flux and the first shear pin 34, allowing the solid flux to come into contact with the drilling mud. The solid flux dissolves under the influence of the drilling mud, rapidly dissolving the soluble pin (first shear pin 34). Once the soluble pin's strength is reduced due to dissolution, it is not necessary to increase the pump pressure. The soluble pin can be sheared off using a pressure no higher than the pressure of the liquid column or the circulating pressure at which the fractured disc 22 ruptures. This causes the first shear pin sleeve 31 to accelerate downwards, impacting the remaining debris of the fractured disc 22 again. The second shear pin sleeve 33 and the first shear pin sleeve 31 impact the rupture disc 22 respectively, ensuring the impact effect and achieving full bore. Even when the liquid column pressure or circulating pressure is low, if the impact force generated by the first shear pin sleeve 31 cannot completely remove the residue from the rupture disc 22, the constant pressure difference within the tubing (i.e., within the floating coupling) allows the first and second shear pin sleeves 31 and 33 to crush the residue after the rupture disc 22 ruptures. Because the residue after the rupture disc 22 ruptures lacks integrity, its compressive strength decreases significantly under impact crushing, thus allowing the residue to be broken into fine particles through compression, achieving full bore. Under this configuration, on the one hand, the pumping pressure required during operation does not need to exceed the blasting pressure of the rupture disc 22, thus solving the problem that mud may invade the formation under high pressure; on the other hand, the first shear pin 34 is a soluble pin, which reduces the strength of the first shear pin 34 by dissolving it, enabling it to more reliably complete the impact action of the first shear pin sleeve 31, and avoiding the situation where the first shear pin 34 cannot be sheared under the pressure operation window.

[0044] It is easy to understand that the isolation fluid, high-strength soluble material, and solid co-solvent are all existing materials. After the solid co-solvent comes into contact with the mud, it can promote the dissolution of the high-strength soluble material.

[0045] According to the method of crushing and breaking the disc provided by the present invention, the floating coupling 100 provided by the present invention can achieve full bore, and the design strength of the first shear pin 34 and the second shear pin 35 can be within a wide range, thereby reducing the design difficulty of the first shear pin 34 and the second shear pin 35. The strength requirement of the shear pin sleeve is also much lower than that of the prior art. Furthermore, the pumping pressure in the present invention can also be within a wide range, thereby reducing the difficulty of controlling the pumping pressure.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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: The upper connector (1) includes a connector portion (11) and an assembly portion (12), wherein the inner diameter of the assembly portion is larger than the inner diameter of the connector portion; The lower connector (4) is provided at the lower end of the assembly part; A sealing assembly (2) is fixedly fitted inside the assembly section; A first shear pin sleeve (31) and a second shear pin sleeve (33) are respectively provided in the assembly part by a first shear pin (34) and a second shear pin (35); The first shear pin sleeve (31) and the second shear pin sleeve (33) are respectively disposed above and below the sealing assembly. The area of ​​the pressure-bearing surface of the first shear pin sleeve (31) and the second shear pin sleeve (33) away from the sealing assembly is larger than the area of ​​the pressure-bearing surface close to the sealing assembly, so that the first shear pin sleeve can cut the shear pin under pressure and hit the sealing assembly. The first shear pin (34) is a soluble pin. After the floating coupling is inserted into the well, during the grouting process, a section of isolation fluid is first pumped in to protect the first shear pin (34), and then mud that can dissolve the first shear pin is pumped in. After the pumping pressure is reached, the plugging assembly breaks before the first shear pin, and then the first shear pin (34) is dissolved, so that the first shear pin sleeve (31) impacts the residual part after the plugging assembly explodes.

2. The floating coupling according to claim 1, characterized in that, The upper part of the lower connector (4) extends into the assembly part and abuts against the sealing assembly (2).

3. The floating coupling according to claim 2, characterized in that, A connecting tube (32) is sleeved between the first shear pin sleeve (31) and the assembly part (12). The upper and lower ends of the connecting tube abut against the joint part (11) and the sealing assembly (2) respectively. The first shear pin sleeve is fixedly connected to the connecting tube by shear pins.

4. The floating coupling according to claim 3, characterized in that, The first clipper sleeve (31) includes a first fitting part (311) and a second fitting part (312). The outer diameter of the first fitting part is larger than the outer diameter of the second fitting part, and the inner diameter of the first fitting part is equal to the inner diameter of the second fitting part. The connecting cylinder (32) includes a third fitting part (321) and a fourth fitting part (322). The inner diameter of the third fitting part is larger than the inner diameter of the fourth fitting part. A sealing element is provided between the first fitting part and the third fitting part, and a sealing element is provided between the second fitting part and the fourth fitting part.

5. The floating coupling according to claim 4, characterized in that, The sealing assembly (2) includes a base (21) and a rupture disc (22) fixedly disposed on the base, the rupture disc being capable of sealing the base.

6. The floating coupling according to claim 5, characterized in that, The base (21) includes a fifth fitting part (23) and a sixth fitting part (24) disposed at the lower end of the fifth fitting part. The inner diameter of the fifth fitting part is smaller than the inner diameter of the sixth fitting part. The second shear pin sleeve (33) includes a seventh fitting part (331) and an eighth fitting part (332) disposed at the lower end of the seventh fitting part (331). The outer diameter of the seventh fitting part is smaller than the outer diameter of the eighth fitting part. The inner diameter of the seventh fitting part is equal to the inner diameter of the eighth fitting part. The seventh fitting part is sealed inside the fifth fitting part. The eighth fitting part is sealed inside the sixth fitting part. The eighth fitting part and the sixth fitting part are fixedly connected by shear pins.

7. The floating coupling according to claim 6, characterized in that, A first step (231) is provided on the inner wall of the fifth fitting part (23), and the rupture disc (22) is provided on the first step (231). The two ends of the rupture disc abut against the stepped surface of the first step and the fourth fitting part (322) respectively. An end face sealing ring (5) is provided between the rupture disc (22) and the fourth fitting part (322).

8. The floating coupling according to claim 7, characterized in that, The outer diameter of the second fitting part (312) is equal to the outer diameter of the seventh fitting part (23).

9. The floating coupling according to any one of claims 5 to 8, characterized in that, The rupture disc (22) is made of a high-pressure resistant and fragile non-metallic material, including glass, ceramics, and resin. The rupture disc (22) is cylindrical or spherical.

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