A reusable casing head apparatus and fracturing method

Abstract

The application belongs to the technical field of casing heads for drilling, and particularly provides a reusable casing head device and a fracturing construction method. The reusable casing head device comprises a support plate, a casing head, a sealing assembly and a suspension assembly. The support plate is connected with an outer casing, the casing head is sleeved on the outer periphery of an inner casing, the suspension assembly comprises a plurality of connecting units arranged in a mounting cavity, and a telescopic driving mechanism can drive the plurality of connecting units to move synchronously in the radial direction, so as to clamp and release the inner casing. In the application, the casing head and the support plate are detachably connected, and the sealing between the casing head and the inner casing is realized through the sealing assembly, so that the risk of leakage of the wellhead during fracturing is eliminated, and the sealing requirement of the wellhead fracturing construction can be met. Meanwhile, the clamping or releasing of the inner casing is realized through the suspension assembly with switchable states, so that the casing head can be detached and reused after the fracturing is completed, and the cost of drilling construction is reduced.

Description

Technical Field

[0001] This application belongs to the field of drilling casing head technology, and more specifically, relates to a reusable casing head device and fracturing construction method. Background Technology

[0002] A casing head is a connecting device installed at the wellhead of a drilling well. Its function is to connect the casing below and achieve a seal between the casing layers. In actual production, for wellheads with low or no pressure during drilling, where the requirements for sealing performance are lower, a conventional casing head may not be installed. Instead, a ring-shaped steel plate welded between the inner and outer casing layers can be used as a simple casing head, thereby reducing equipment costs.

[0003] However, when facing wellheads with little or no pressure that require fracturing operations, the simple casing head made of annular steel plates is unable to withstand the high internal pressure during fracturing. This results in significant shaking during fracturing, which can easily lead to stress fatigue, and there is also a risk of leakage at the joints and welds of the annular steel plates. Therefore, to prevent shaking and leakage, conventional casing heads must be installed, which fails to achieve the expected effect of reducing equipment costs. Summary of the Invention

[0004] Based on the above-mentioned technical problems, this application provides a reusable casing head device and fracturing construction method, which not only solves the problem of wellhead leakage during fracturing, but also can be disassembled and reused after fracturing, thereby reducing drilling costs.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] In a first aspect, this application provides a reusable sleeve head device, comprising:

[0007] A support plate is provided around the outer periphery of the outer sleeve;

[0008] A sleeve head is disposed above the support plate and detachably connected to the support plate. The sleeve head has a vertically penetrating mounting cavity for the inner sleeve to pass through. A sealing groove is formed on the upper surface of the sleeve head around the top opening of the mounting cavity.

[0009] A sealing assembly, disposed within the sealing groove, is used to seal the contact surface between the sleeve head and the inner sleeve; and

[0010] The suspension assembly includes multiple connecting units and a telescopic drive mechanism. The multiple connecting units are disposed in the mounting cavity surrounding the inner sleeve. The connecting units have a suspended state connected to the inner sleeve and a released state separated from the inner sleeve. The telescopic drive mechanism is used to drive the multiple connecting units to move synchronously along the radial direction of the inner sleeve, so that the connecting units switch between the suspended state and the released state.

[0011] In one possible implementation, the sleeve head includes:

[0012] A first body is disposed above the support plate and forms the mounting cavity. The side wall of the mounting cavity has connecting holes penetrating the wall thickness of the first body, and each connecting hole corresponds to a connecting unit.

[0013] The second body is disposed around the outer periphery of the first body, the telescopic drive mechanism is disposed on the second body, and the suspension assembly further includes a force transmission rod, the force transmission rod is slidably sealed with the connecting hole, one end of the force transmission rod is connected to the connecting unit, and the other end is connected to the telescopic drive mechanism.

[0014] In one possible implementation, the top wall of the mounting cavity is provided with a plurality of sliding grooves, each corresponding to a connecting unit. The sliding grooves extend radially along the inner sleeve, and the two opposite side walls of the sliding grooves extend into the groove to form support portions.

[0015] The connecting unit includes a sliding part that slides with the groove and a connecting part that connects with the inner sleeve. The sliding part is located above the support part.

[0016] In one possible implementation, the telescopic drive mechanism includes a plurality of electrically operated telescopic rods spaced circumferentially along the inner sleeve, the telescopic ends of the electrically operated telescopic rods being arranged radially along the inner sleeve and connected to the corresponding force transmission rods.

[0017] In one possible implementation, the end of the force transmission rod away from the connecting unit has a stop portion formed circumferentially around itself, and the telescopic drive mechanism includes:

[0018] A drive ring is coaxially sleeved on the outer periphery of the first body and rotates with the second body. The inner sidewall of the drive ring is provided with a plurality of drive parts spaced apart along its circumference. Each drive part corresponds to a force transmission rod. The drive part gradually tilts towards the center of the drive ring in the circumferential direction to form a guide surface with one end close to the center of the drive ring and the other end close to the inner wall of the drive ring. The end of the force transmission rod away from the connecting unit abuts against the guide surface.

[0019] Multiple elastic elements are correspondingly disposed on the force transmission rod. One end of each elastic element abuts against the stop portion, and the other end abuts against the first body. Each elastic element is configured with a preload that causes the force transmission rod to move towards the drive ring.

[0020] A rotary drive component, located on the second body, is used to drive the drive to rotate around its own central axis.

[0021] In one possible implementation, the outer wall of the inner sleeve is formed with an annular limiting boss, and the side of the connecting unit that is in contact with the inner sleeve is an arc-shaped limiting groove. When the connecting unit is in the suspended state, the connecting unit is supported below the limiting boss.

[0022] In one possible implementation, the connecting unit is further provided with a fall arresting wheel on the side adjacent to the inner sleeve. The fall arresting wheel is eccentrically rotatably connected to the connecting unit, and the outer periphery of the fall arresting wheel is covered with a layer of rubber material.

[0023] The fall arrestor wheel is defined to have a large-diameter side and a small-diameter side. The distance between the outer circumferential surface of the small-diameter side and the axis is less than the distance between the outer circumferential surface of the large-diameter side and the axis. In the initial state, the small-diameter side faces the inner sleeve. The shaft of the fall arrestor wheel is connected to a torsion spring, and the torsion spring is configured with a preload to reset the fall arrestor wheel to the initial state.

[0024] In one possible implementation, the sealing assembly includes:

[0025] Two mounting rings are spaced apart vertically within the sealing groove, and the mounting rings have multiple mounting holes along their circumference.

[0026] An elastic sealing element, ring-shaped, is disposed between the two mounting rings, and the elastic sealing element has clearance holes corresponding to the upper and lower parts of the mounting hole; and

[0027] Multiple fasteners are provided, each corresponding to one of the mounting holes. The fasteners pass through the upper mounting hole and are threaded into the lower mounting hole.

[0028] In one possible implementation, the mounting ring has two extrusion bosses on one side for fitting the elastic sealing element, and the two extrusion bosses are concentrically arranged and located on both sides of the mounting hole respectively; the cross-section of the extrusion boss is trapezoidal, with the long side of the trapezoid adjacent to the mounting ring and the short side of the trapezoid adjacent to the elastic sealing element.

[0029] The upper and lower surfaces of the elastic sealing element are respectively provided with extrusion grooves, and the extrusion grooves are trapezoidal grooves adapted to the extrusion boss.

[0030] Compared with the prior art, the beneficial effects of the reusable sleeve head device provided in this application are:

[0031] This application provides a reusable casing head device comprising a support plate, a casing head, a sealing assembly, and a suspension assembly. In use, the support plate is connected to the outer casing, and the casing head is detachably connected to the support plate and fitted onto the outer periphery of the inner casing. The suspension assembly includes multiple connecting units disposed within an installation cavity. A telescopic drive mechanism drives the multiple connecting units to move synchronously radially, achieving clamping and release of the inner casing. During fracturing operations, the connecting units are in a suspended state, clamping the inner casing. The sealing assembly seals the contact surface between the casing head and the inner casing, preventing leakage due to excessive pressure during fracturing and ensuring the smooth progress of the fracturing operation. After fracturing, the telescopic drive mechanism can control the connecting units to switch from the suspended state to the released state, allowing the casing head to be removed from the inner casing, thus achieving reusability.

[0032] This application features a support plate around the outer casing, with the casing head and support plate detachably connected. A sealing assembly ensures a seal between the casing head and the inner casing, eliminating the risk of leakage at the wellhead during fracturing and meeting the sealing requirements for wellhead fracturing operations. Furthermore, this application utilizes a switchable suspension assembly to clamp or release the inner casing, allowing the casing head to be removed and reused after fracturing, thus reducing drilling costs.

[0033] Secondly, this application provides a fracturing construction method, employing a reusable casing head device as described in any of the above implementations, comprising the following steps:

[0034] The inner and outer sleeves are cut and their edges are ground so that the top height of the outer sleeve is lower than that of the inner sleeve.

[0035] A support plate is fixedly connected to the outer sleeve;

[0036] Assemble the casing head and the suspension assembly together, hoist the casing head onto the support plate and connect and fix it to the support plate. Initially, the connecting unit of the suspension assembly is in the released state, allowing the upper end of the inner casing to pass through the top opening of the mounting cavity. Then, the connecting unit of the suspension assembly is switched to the suspended state by the telescopic drive mechanism to clamp the inner casing.

[0037] Install the sealing assembly into the sealing groove;

[0038] The upper surface of the casing head is provided with an annular flange sealing groove. A sealing ring or gasket is installed into the flange sealing groove, and a fracturing wellhead is installed above the casing head.

[0039] Bolts and nuts are used to connect the flanges of the fracturing wellhead and the casing head. Tightening the bolts and nuts will cause the clamping force to press the sealing ring or gasket together to achieve a seal.

[0040] The fracturing operation is carried out by connecting the fracturing truck to the fracturing wellhead and delivering pressure into the well through the inner casing.

[0041] After the fracturing operation is completed, remove the bolts and nuts to separate the flange of the casing head from the fracturing wellhead. Remove the fracturing wellhead, take out the gasket or sealing ring from the flange sealing groove, take out the sealing assembly from the sealing groove, switch the connection unit of the suspension assembly to the release state through the telescopic drive mechanism, remove the connecting parts between the casing head and the support plate, and lift the casing head from above the support plate.

[0042] A sealing cover is welded between the outer and inner sleeves to seal the annular gap between them.

[0043] The fracturing construction method provided in this application is applicable to fracturing construction at wellheads with low or no pressure, and has the same technical effect as the aforementioned reusable casing head device, which will not be described in detail here. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A three-dimensional structural diagram of a reusable sleeve head device provided in Embodiment 1 of this application;

[0046] Figure 2 This is a longitudinal perspective sectional view of the connecting unit in the suspended state in Embodiment 1 of this application;

[0047] Figure 3 for Figure 2 Enlarged view of part A in the middle;

[0048] Figure 4 A perspective sectional view in the horizontal direction of a reusable sleeve head device provided in Embodiment 1 of this application;

[0049] Figure 5 This is a partial perspective sectional view of the connecting unit in the released state in Embodiment 1 of this application;

[0050] Figure 6 This is a three-dimensional structural diagram of the inner and outer sleeves;

[0051] Figure 7 A perspective view of a reusable sleeve head device provided in Embodiment 2 of this application;

[0052] Figure 8 This is a longitudinal sectional view of a reusable sleeve head device provided in Embodiment 2 of this application;

[0053] Figure 9 This is an internal cross-sectional view of the sealing assembly;

[0054] Figure 10 An exploded view of the sealing assembly;

[0055] Figure 11 For Figure 10 Enlarged view of part B in the middle;

[0056] Explanation of reference numerals in the attached figures:

[0057] 10. Support plate; 20. Sleeve head; 21. First body; 211. Mounting cavity; 212. Sealing groove; 213. Slide groove; 22. Second body; 30. Sealing assembly; 31. Mounting ring; 311. Extrusion boss; 32. Elastic sealing element; 321. Extrusion groove; 33. Fastener; 40. Suspension assembly; 41. Connecting unit; 411. Sliding part; 412. Connecting part; 42. Telescopic drive mechanism; 421. Drive ring; 4211. Drive part; 4212. Guide surface; 422. Elastic element; 423. Rotation drive component; 43. Force transmission rod; 431. Stop part; 44. Anti-fall wheel; 441. Large diameter side; 442. Small diameter side; 50. Inner sleeve; 51. Limiting boss; 60. Outer sleeve. Detailed Implementation

[0058] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0059] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0060] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0061] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0063] Please refer to the following: Figures 1 to 11 The following describes a reusable casing head device and fracturing construction method provided in this application.

[0064] The reusable casing head device and fracturing construction method provided in this application are applicable to low-pressure or no-pressure drilling fracturing construction. They can be dismantled and reused after fracturing is completed, thereby reducing drilling construction costs.

[0065] For details, please refer to Figures 1 to 5 Embodiment 1 of this application provides a reusable sleeve head device, including a support plate 10, a sleeve head 20, a sealing assembly 30, and a suspension assembly 40. A support plate 10 is disposed around the outer periphery of the outer sleeve 60; a sleeve head 20 is disposed above the support plate 10 and detachably connected to the support plate 10. The sleeve head 20 has a vertically penetrating mounting cavity 211 for the inner sleeve 50 to pass through. A sealing groove 212 is formed on the upper surface of the sleeve head 20 around the top opening of the mounting cavity 211; a sealing assembly 30 is disposed in the sealing groove 212 for sealing the contact surface between the sleeve head 20 and the inner sleeve 50; the suspension assembly 40 includes multiple connecting units 41 and a telescopic drive mechanism 42. The multiple connecting units 41 are disposed around the inner sleeve 50 in the mounting cavity 211. The connecting units 41 have a suspended state connected to the inner sleeve 50 and a released state separated from the inner sleeve 50. The telescopic drive mechanism 42 is used to drive the multiple connecting units 41 to move synchronously along the radial direction of the inner sleeve 50 so that the connecting units 41 switch between the suspended state and the released state.

[0066] Compared with the prior art, the beneficial effects of the reusable sleeve head device provided in Embodiment 1 of this application are:

[0067] This application provides a reusable casing head device according to Embodiment 1, comprising a support plate 10, a casing head 20, a sealing assembly 30, and a suspension assembly 40. In use, the support plate 10 is connected to the outer casing 60, and the casing head 20 is detachably connected to the support plate 10 and fitted onto the outer periphery of the inner casing 50. The suspension assembly 40 includes multiple connecting units 41 disposed within an installation cavity 211. A telescopic drive mechanism 42 drives the multiple connecting units 41 to move synchronously radially, achieving clamping and releasing of the inner casing 50. During fracturing operations, the connecting units 41 are in a suspended state, clamping the inner casing 50. The sealing assembly 30 seals the contact surface between the casing head 20 and the inner casing 50, preventing leakage due to excessive pressure during fracturing and ensuring the smooth progress of the fracturing operation. After fracturing, the telescopic drive mechanism 42 can control the connecting units 41 to switch from the suspended state to the released state, allowing the casing head 20 to be removed from the inner casing 50, thus achieving reusability.

[0068] In Embodiment 1 of this application, a support plate 10 is provided around the outer casing 60. The casing head 20 and the support plate 10 are detachably connected, and a sealing assembly 30 is used to achieve a seal between the casing head 20 and the inner casing 50, eliminating the risk of leakage at the wellhead during fracturing and meeting the sealing requirements of wellhead fracturing operations. Simultaneously, this application also uses a switchable suspension assembly 40 to clamp or release the inner casing 50, allowing the casing head 20 to be removed and reused after fracturing, reducing drilling costs compared to installing conventional casing heads. After fracturing, a ring-shaped steel plate can be welded between the inner casing 50 and the outer casing 60 to serve as a simple casing head. The removed casing head assembly can be reused in different drilling operations.

[0069] like Figure 6 As shown, before construction, the outer sleeve 60 needs to be cut and ground. The top of the inner sleeve 50 should be higher than the outer sleeve 60, and the edges should be flat and free of burrs, and the outer surface should be free of oil stains and rust.

[0070] After grinding is completed, the support plate 10 is connected and fixed to the outer sleeve 60. The support plate 10 can be a circular plate, fitted around the outer circumference of the outer sleeve 60. The support plate 10 is made of steel plate and can be fixed to the outer sleeve 60 by welding, screw connection, or other methods. A flange can be provided on the support plate 10, which can be detachably connected to the sleeve head 20 by bolts or other fasteners. After fracturing is completed, the support plate 10 can be removed or retained as needed.

[0071] The sleeve head 20 has a through mounting cavity 211. After installation, the bottom surface of the sleeve head 20 contacts the upper surface of the support plate 10, and the inner sleeve 50 passes through the mounting cavity 211. The mounting cavity 211 can be annular or other shapes. The sealing assembly 30 is provided at the top opening of the mounting cavity 211 to achieve a seal.

[0072] To ensure the sealing of the contact surface between the support plate 10 and the casing head 20 during fracturing operations, a sealing gasket or sealant can be placed between them. The sealing gasket and the aforementioned sealing assembly 30 can be sealing elements made of metal or rubber, and can be a single part or an assembly composed of multiple components. Existing sealing products on the market can be directly selected for the sealing gasket and sealing assembly 30; there are no restrictions on their specific type or model, as long as they meet the sealing requirements during fracturing operations.

[0073] The suspension assembly 40 includes multiple connecting units 41 and a telescopic drive mechanism 42 that drives the multiple connecting units 41 to move synchronously. The multiple connecting units 41 are arranged in a circumferential array on the outer periphery of the inner casing 50 and are used to support the inner casing 50 during fracturing operations. Specifically, the connecting unit 41 can be a block or other shaped component that can be connected to the inner casing 50. When the multiple connecting units 41 are in the suspended state, they can clamp the inner casing 50. When the connecting unit 41 is in the released state, it separates from the inner casing 50.

[0074] The telescopic drive mechanism 42 can be a telescopic cylinder, an electric telescopic rod, or other power component that can drive the connecting unit 41 to achieve radial movement.

[0075] Since the sleeve head 20 is mostly installed onto the inner sleeve 50 using a crane, a lifting ring can be provided at the upper end of the sleeve head 20 for convenient lifting. The lifting ring is fixed or detachable and used to connect the lifting rope. In addition to the suspended and released states described above, the connecting unit 41 also has a positioning state for guiding the installation of the sleeve head 20. Specifically, to improve the installation accuracy of the sleeve head 20, during the process of lowering the sleeve head 20 to the support plate 10, the telescopic drive mechanism 42 can control the connecting unit 41 to move towards the inner sleeve 50, so that the connecting unit 41 is in close contact with or at a small distance from the outer wall of the inner sleeve 50. At this time, the connecting unit 41 is in the positioning state. In the positioning state, multiple connecting units 41 can achieve concentric alignment of the sleeve head 20 and the inner sleeve 50 during the descent of the sleeve head 20, making the installation positioning of the sleeve head 20 and the inner sleeve 50 more convenient, faster, and more accurate.

[0076] In this embodiment, the suspension component 40 can be used to clamp and suspend the inner casing 50 during fracturing operations, and can also be used for alignment and positioning during the hoisting of the casing head 20, achieving two goals at once.

[0077] Further, please refer to Figure 1 , Figure 2 , Figure 3 and Figure 5 The sleeve head 20 includes a first body 21 and a second body 22. The first body 21 is located above the support plate 10 and forms an installation cavity 211. The side wall of the installation cavity 211 has a connecting hole that penetrates the wall thickness of the first body 21. The connecting hole corresponds one-to-one with the connecting unit 41. The second body 22 is arranged around the outer periphery of the first body 21. The telescopic drive mechanism 42 is located on the second body 22. The suspension assembly 40 also includes a force transmission rod 43. The force transmission rod 43 is slidably sealed with the connecting hole. One end of the force transmission rod 43 is connected to the connecting unit 41, and the other end is connected to the telescopic drive mechanism 42.

[0078] The casing head 20 is functionally divided into a first body 21 and a second body 22. The first body 21 and the second body 22 can be integrally connected by welding, or they can be detachably connected by bolts or other connecting parts. The first body 21 forms an installation cavity 211. The lower part of the first body 21 is sealed with the support plate 10, and the upper part is sealed with the inner casing 50 through the sealing component 30, which can ensure that no leakage occurs during fracturing operations.

[0079] The telescopic drive mechanism 42 is mounted on the second body 22, which is located outside the first body 21. The telescopic drive mechanism 42 transmits power to the connecting unit 41 via a force transmission rod 43. In this embodiment, the telescopic drive mechanism 42 is positioned outside the first body 21, which facilitates maintenance of the telescopic drive mechanism 42 and improves its practicality. The first body 21 and the second body 22 can be connected and fixed by welding or bolting.

[0080] The force transmission rod 43 can be a round, square or other shaped steel component. The force transmission rod 43 and the connecting hole should have a high fitting accuracy, and a sealing ring should be provided to achieve a seal.

[0081] Further, please refer to Figure 3 and Figure 5To improve the load-bearing capacity of the connecting unit 41, the top wall of the mounting cavity 211 is provided with multiple sliding grooves 213. Each sliding groove 213 corresponds to a connecting unit 41. The sliding groove 213 extends radially along the inner sleeve 50. The opposite side walls of the sliding groove 213 extend into the groove to form support portions, thereby obtaining a sliding groove 213 with an inverted T-shaped cross-section. The connecting unit 41 includes a sliding portion 411 that slides with the sliding groove 213, and a connecting portion 412 that connects to the inner sleeve 50. The sliding portion 411 is located above the support portion, and the support portion is used to provide support for the sliding portion 411.

[0082] The support part is a protrusion formed on the side wall of the groove 213, which can support the sliding part 411 of the connecting unit 41, improve the load-bearing strength of the connecting unit 41, and make the connecting unit 41 less prone to deformation, breakage and other failure problems after multiple uses, thus meeting the requirement of reusability.

[0083] The specific structural form of the telescopic drive mechanism 42 is not limited. For example, the telescopic drive mechanism 42 may include multiple electric telescopic rods arranged circumferentially along the inner sleeve 50. The telescopic ends of the electric telescopic rods are connected to the force transmission rods 43. The multiple electric telescopic rods extend or retract synchronously, driving the multiple force transmission rods 43 and the connecting unit 41 to move synchronously.

[0084] Or, such as Figure 4 and Figure 8 As shown, in Embodiment 1 or Embodiment 2, a stop portion 431 is formed circumferentially around the end of the force transmission rod 43 away from the connecting unit 41. The telescopic drive mechanism 42 includes a drive ring 421, an elastic element 422, and a rotary drive member 423. The drive ring 421 is coaxially sleeved on the outer periphery of the first body 21 and rotates with the second body 22. The inner sidewall of the drive ring 421 is provided with a plurality of drive portions 4211 spaced apart along its circumference. Each drive portion 4211 corresponds to a force transmission rod 43. The drive portions 4211 gradually tilt towards the center of the drive ring 421 in the circumferential direction to form a guide surface 4212 with one end close to the center of the drive ring 421 and the other end close to the inner wall of the drive ring 421. The force transmission rod 43 is away from the connecting unit 41. One end of the force transmission rod 43 abuts against the guide surface 4212, and the end of the force transmission rod 43 away from the connecting unit 41 abuts against the driving part 4211; a plurality of elastic elements 422 are correspondingly provided on the force transmission rod 43, one end of the elastic element 422 abuts against the stop part 431, and the other end abuts against the first body 21, and the elastic element 422 is configured with a preload force to move the force transmission rod 43 toward the driving ring 421; the rotary drive member 423 is provided on the second body 22 and is used to drive the driving ring 421 to rotate around its own central axis.

[0085] The telescopic drive mechanism 42 includes a drive ring 421, an elastic element 422, and a rotary drive member 423. The drive ring 421 is annular, and its inner wall has multiple drive portions 4211. Each drive portion 4211 corresponds to a multiple force transmission rod 43, and the end of each force transmission rod 43 abuts against the guide surface 4212 of the drive portion 4211. Figure 8 For example, when the drive ring 421 rotates counterclockwise, the guide surface 4212 can push the force transmission rod 43 to extend and retract inward against the preload of the elastic element 422, causing the connecting unit 41 to clamp the inner sleeve 50. When the drive ring 421 rotates clockwise, under the action of the preload, the elastic element 422 pushes the force transmission rod 43 to reset, causing the connecting unit 41 to move away from the inner sleeve 50. To reduce resistance, the end of the force transmission rod 43 that abuts against the guide surface 4212 can be designed as a spherical surface.

[0086] The rotary drive component 423 can be a power device such as an electric motor or hydraulic motor that can output rotary motion. The output shaft of the rotary drive component 423 can drive the drive ring 421 to rotate through gear transmission, chain transmission, or other means.

[0087] Please see Figure 1 , Figure 2 and Figure 6 In Embodiment 1, the outer wall of the inner sleeve 50 is formed with an annular limiting boss 51. The connecting unit 41 is used to fit the inner sleeve 50 with an arc-shaped limiting groove on one side. When the connecting unit 41 is in a suspended state, the connecting unit 41 is supported under the limiting boss 51.

[0088] Multiple connecting units 41 are assembled to form a ring-shaped support ring. The limiting boss 51 can be machined from the inner sleeve 50, specifically by turning it on a machine tool before the last inner sleeve 50 is inserted, or it can be an existing pipe clamp. The function of the limiting boss 51 is to facilitate the support of the connecting unit 41.

[0089] Please see Figure 7 and Figure 8 Unlike Embodiment 1, in Embodiment 2, the connecting unit 41 is further provided with a fall arrester 44 on the side adjacent to the inner sleeve 50. The fall arrester 44 is eccentrically rotatably connected to the connecting unit 41, and the outer periphery of the fall arrester 44 is covered with a rubber material layer. The outer periphery of the fall arrester 44 is defined as the large diameter side 441 and the small diameter side 442, with an angle of 180° between the large diameter side 441 and the small diameter side 442. The distance between the outer periphery of the small diameter side 442 and the axis is less than the distance between the outer periphery of the large diameter side 441 and the axis. In the initial state (e.g.) Figure 8As shown), the small diameter side 442 faces the inner sleeve 50; the shaft of the anti-fall wheel 44 is connected to a torsion spring, which is configured with a preload to reset the anti-fall wheel 44 to its initial state. The torsion spring being mounted on the shaft for resetting wheel-like parts is a common practice in the art, and there are no specific limitations on its installation method, shape, or specifications.

[0090] like Figure 8 As shown, in the suspended state, the small-diameter side 442 of the anti-fall wheel 44 abuts against the outer wall of the inner sleeve 50. There is friction between the rubber material layer covering the outer wall of the anti-fall wheel 44 and the inner sleeve 50. When the inner sleeve 50 tends to fall, the anti-fall wheel 44 has a tendency to rotate from the small-diameter side 442 to the large-diameter side 441. During the rotation towards the large-diameter side 441, the rubber material layer is further compressed, which increases the friction between the anti-fall wheel 44 and the inner sleeve 50, thereby overcoming the downward force of the inner sleeve 50.

[0091] In Embodiment 1, to make the connecting unit 41 more stably support the inner sleeve 50, an additional limiting boss 51 needs to be machined on the inner sleeve 50, which increases the workload of the construction party. For easier construction, Embodiment 2 uses an eccentrically positioned anti-fall wheel 44 that contacts the inner sleeve 50. When the inner sleeve 50 tends to fall, the frictional force generated by the anti-fall wheel 44 increases, thereby overcoming the downward force and keeping the inner sleeve 50 in its original position. With this design, it is not necessary to additionally create a limiting boss 51 on the inner sleeve 50, making construction more convenient.

[0092] Please see Figure 9 , Figure 10 and Figure 11 In Embodiment 1 or Embodiment 2, the sealing assembly 30 includes a mounting ring 31, an elastic sealing element 32, and fasteners 33. Two mounting rings 31 are spaced apart vertically within the sealing groove 212, and each mounting ring 31 has multiple mounting holes along its circumference. The elastic sealing element 32 is annular and is located between the two mounting rings 31. The elastic sealing element 32 has clearance holes corresponding to the mounting holes vertically. Multiple fasteners 33 correspond one-to-one with the mounting holes. The fasteners 33 pass through the upper mounting hole and are threaded into the lower mounting hole.

[0093] In this embodiment, two mounting rings 31 are arranged vertically opposite each other. The mounting hole of the upper mounting ring 31 is a smooth hole, while the mounting hole of the lower mounting ring 31 is a threaded hole. In use, the mounting rings 31, the elastic sealing element 32, and the fasteners 33 are first assembled together, without tightening the fasteners 33. Then, the assembled sealing assembly 30 is placed into the sealing groove 212, and the fasteners 33 are gradually tightened. During the tightening process, the two mounting rings 31 move closer to each other, which can compress the elastic sealing element 32, causing the elastic sealing element 32 to expand to both sides, thereby sealing the contact surface between the inner sleeve 50 and the sleeve head 20.

[0094] It is important to note that since multiple fasteners 33 are arranged along the circumference of the mounting ring 31, they must be tightened alternately and in stages during tightening; otherwise, the sealing effect will be affected. Specifically, the multiple fasteners 33 should be tightened sequentially and in stages in a diagonal and clockwise direction. This can be done in two stages: the first stage is tightened to approximately 50% of the rated torque, and the second stage is tightened to 100% of the rated torque.

[0095] Please see Figure 9 Figure 10 and Figure 11 Furthermore, the mounting ring 31 has two extrusion bosses 311 on one side for fitting the elastic sealing element 32. The extrusion bosses 311 are concentrically arranged and located on both sides of the mounting hole. The cross-section of the extrusion bosses 311 is trapezoidal, with the long side of the trapezoid adjacent to the mounting ring 31 and the short side adjacent to the elastic sealing element 32. The upper and lower surfaces of the elastic sealing element 32 are respectively provided with extrusion grooves 321 that are adapted to the extrusion bosses 311.

[0096] During the tightening process of fastener 33, the two mounting rings 31 approach each other under the clamping force of fastener 33. The extrusion boss 311 can extrude the elastic sealing element 32, so that the elastic sealing element 32 spreads evenly to the outer periphery under the action of clamping force, sealing the contact surface. On the one hand, it can improve the sealing effect and pressure resistance, and on the other hand, it can avoid uneven deformation of the sealing surface of the elastic sealing element 32, so that the elastic sealing element 32 can be reused and still has good sealing performance when reused.

[0097] Secondly, this application provides a fracturing construction method, employing a reusable casing head device provided in Embodiment 1 or Embodiment 2 above, comprising the following steps:

[0098] The outer sleeve 60 is cut and its edges are ground so that the top height of the outer sleeve 60 is lower than the top height of the inner sleeve 50.

[0099] A support plate 10 is fixedly connected to the outer sleeve 60, which can be fixed by welding, bolt connection or other methods.

[0100] After the outer sleeve 60 and support plate 10 are installed, the sleeve head 20 can be installed. When installing the sleeve head 20, first assemble the sleeve head 20 and the suspension assembly 40 together, connect the lifting rope through the lifting ring, and use a crane to lift the sleeve head 20 onto the support plate 10. Then connect and fix the sleeve head 20 to the support plate 10. Initially, the connecting unit 41 of the suspension assembly 40 is in the released state, allowing the upper end of the inner sleeve 50 to pass through the top opening of the mounting cavity 211. Then, the telescopic drive mechanism 42 switches the connecting unit 41 of the suspension assembly 40 to the suspended state to clamp the inner sleeve 50.

[0101] Install the sealing assembly 30 into the sealing groove 212 to seal the inner sleeve 50 and the sleeve head 20.

[0102] The inner casing 50 is connected to the output end of the fracturing truck. The fracturing truck delivers pressure into the wellbore through the inner casing 50 for fracturing operations. Specifically, an annular flange sealing groove is provided on the upper surface of the casing head 20. A sealing ring or gasket is installed into the flange sealing groove. A fracturing wellhead is installed above the casing head 20. Bolts and nuts are used to connect the fracturing wellhead and the flange of the casing head 20. Tightening the bolts and nuts compresses the sealing ring or gasket to achieve a seal. The fracturing truck is connected through the fracturing wellhead, and pressure is delivered into the wellbore through the inner casing 50 for fracturing operations.

[0103] Fracturing trucks are used to inject high-pressure, high-volume fracturing fluid into wells to break up the formation and force proppant into the fractures, thus completing the fracturing operation. The specific structure and usage of fracturing trucks and fracturing wellheads are existing technologies and will not be described in detail here.

[0104] After the fracturing operation is completed, remove the bolts and nuts to separate the flange of the casing head 20 from the fracturing wellhead, and remove the fracturing wellhead. Remove the sealing gasket or sealing ring from the flange sealing groove, remove the sealing assembly 30 from the sealing groove 212, switch the connecting unit 41 of the suspension assembly 40 to the release state through the telescopic drive mechanism 42, disassemble the connecting parts between the casing head 20 and the support plate 10, and lift the casing head 20 from above the support plate 10. To ensure that the casing head 20 can be lifted out from above, the opening diameter of the mounting cavity 211 should be larger than the outer diameter of the inner casing 50.

[0105] A sealing cover is welded between the outer sleeve 60 and the inner sleeve 50 to close the annular gap between the outer sleeve 60 and the inner sleeve 50. Specifically, the sealing cover can be an annular plate-shaped component formed by two or more sector plates, which serves to close the gap between the inner sleeve 50 and the outer sleeve 60 and to suspend the inner sleeve 50.

[0106] It is understood that the parts in the above embodiments can be freely combined or deleted to form different combined embodiments. The specific contents of each combined embodiment will not be repeated here. After this description, it can be considered that the present invention specification has recorded each combined embodiment and can support different combined embodiments.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A reusable sleeve head device, characterized in that, include: A support plate (10) is provided around the outer periphery of the outer sleeve (60); A sleeve head (20) is disposed above the support plate (10) and is detachably connected to the support plate (10). The sleeve head (20) has an installation cavity (211) for the inner sleeve (50) to pass through. A sealing groove (212) is formed on the upper surface of the sleeve head (20) around the top opening of the installation cavity (211). A sealing assembly (30), disposed within the sealing groove (212), is used to seal the contact surface between the sleeve head (20) and the inner sleeve (50); and The suspension assembly (40) includes a plurality of connecting units (41) and a telescopic drive mechanism (42). The plurality of connecting units (41) are disposed in the mounting cavity (211) surrounding the inner sleeve (50). The connecting unit (41) has a suspended state connected to the inner sleeve (50) and a released state separated from the inner sleeve (50). The telescopic drive mechanism (42) is used to drive the plurality of connecting units (41) to move synchronously along the radial direction of the inner sleeve (50) so that the connecting unit (41) switches between the suspended state and the released state. The sleeve head (20) includes: The first body (21) is disposed above the support plate (10) and forms the mounting cavity (211). The side wall of the mounting cavity (211) has a connecting hole penetrating the wall thickness of the first body (21), and the connecting hole corresponds one-to-one with the connecting unit (41). The second body (22) is coaxially connected to the first body (21). The telescopic drive mechanism (42) is located on the second body (22). The suspension assembly (40) also includes a force transmission rod (43). The force transmission rod (43) is slidably sealed with the connecting hole. One end of the force transmission rod (43) is connected to the connecting unit (41), and the other end is connected to the telescopic drive mechanism (42). The end of the force transmission rod (43) away from the connecting unit (41) has a stop portion (431) formed circumferentially around itself, and the telescopic drive mechanism (42) includes: A drive ring (421) is coaxially sleeved on the outer periphery of the first body (21) and rotates with the second body (22). The inner sidewall of the drive ring (421) is provided with a plurality of drive parts (4211) spaced apart along its circumference. The drive parts (4211) correspond one-to-one with the force transmission rod (43). The drive parts (4211) gradually tilt towards the center of the drive ring (421) in the circumferential direction to form a guide surface (4212) with one end close to the center of the drive ring (421) and the other end close to the inner wall of the drive ring (421). The end of the force transmission rod (43) away from the connecting unit (41) abuts against the guide surface (4212). Multiple elastic elements (422) are correspondingly disposed on the force transmission rod (43). One end of each elastic element (422) abuts against the stop portion (431), and the other end abuts against the first body (21). The elastic element (422) is configured with a preload force to move the force transmission rod (43) toward the drive ring (421); and A rotation drive (423) is provided on the second body (22) for driving the drive ring (421) to rotate along its own central axis.

2. The reusable sleeve head device according to claim 1, characterized in that, The top wall of the mounting cavity (211) is provided with a plurality of sliding grooves (213), each of which corresponds to a connecting unit (41). The sliding grooves (213) extend radially along the inner sleeve (50), and the two opposite side walls of the sliding grooves (213) extend into the groove to form support portions. The connecting unit (41) includes a sliding part (411) that slides in conjunction with the groove (213) and a connecting part (412) that connects to the inner sleeve (50). The sliding part (411) is located above the support part.

3. The reusable sleeve head device according to claim 1, characterized in that, The telescopic drive mechanism (42) includes a plurality of electric telescopic rods spaced circumferentially along the inner sleeve (50). The telescopic ends of the electric telescopic rods are arranged radially along the inner sleeve (50) and connected to the corresponding force transmission rods (43).

4. The reusable sleeve head device according to claim 1, characterized in that, The outer wall of the inner sleeve (50) is formed with an annular limiting boss (51). When the connecting unit (41) is in the suspended state, the connecting unit (41) is supported below the limiting boss (51).

5. A reusable sleeve head device according to claim 1 or 4, characterized in that, The connecting unit (41) is also provided with a fall arresting wheel (44) on the side adjacent to the inner sleeve (50). The fall arresting wheel (44) is eccentrically rotatably connected to the connecting unit (41), and the outer periphery of the fall arresting wheel (44) is covered with a rubber material layer. The fall arrester wheel (44) is defined to have a large-diameter side (441) and a small-diameter side (442). The distance between the outer circumferential surface of the small-diameter side (442) and the axis is less than the distance between the outer circumferential surface of the large-diameter side (441) and the axis. In the initial state, the small-diameter side (442) faces the inner sleeve (50). The shaft of the fall arrester wheel (44) is connected to a torsion spring, which is configured with a preload to reset the fall arrester wheel (44) to the initial state.

6. The reusable sleeve head device according to claim 1, characterized in that, The sealing assembly (30) includes: Two mounting rings (31) are spaced apart vertically within the sealing groove (212), and the mounting rings (31) have multiple mounting holes along their circumference. An elastic sealing element (32), annular in shape, is disposed between the two mounting rings (31). The elastic sealing element (32) has clearance holes corresponding to the upper and lower parts of the mounting hole; and Multiple fasteners (33) correspond one-to-one with the mounting holes. The fasteners (33) pass through the upper mounting holes and are threaded into the lower mounting holes.

7. A reusable sleeve head device according to claim 6, characterized in that, The mounting ring (31) has a pressing boss (311) on one side for fitting the elastic sealing element (32). There are two pressing bosses (311) and they are arranged concentrically. The two pressing bosses (311) are located on both sides of the mounting hole. The cross-section of the pressing boss (311) is trapezoidal. The long side of the trapezoid is adjacent to the mounting ring (31), and the short side of the trapezoid is adjacent to the elastic sealing element (32). The upper and lower surfaces of the elastic sealing element (32) are respectively provided with extrusion grooves (321), and the extrusion grooves (321) are trapezoidal grooves adapted to the extrusion boss (311).

8. A fracturing construction method, characterized in that, The reusable sleeve head device according to any one of claims 1-7 includes the following steps: A support plate (10) is fixedly connected to the outer sleeve (60); Assemble the sleeve head (20) and the suspension assembly (40) together, suspend the sleeve head (20) on the support plate (10) and connect and fix it to the support plate (10). Initially, the connecting unit (41) of the suspension assembly (40) is in the released state, so that the upper end of the inner sleeve (50) passes through the top opening of the mounting cavity (211). Then, the connecting unit (41) of the suspension assembly (40) is switched to the suspension state by the telescopic drive mechanism (42) to clamp the inner sleeve (50). Install the sealing assembly (30) into the sealing groove (212); The upper surface of the casing head (20) is provided with an annular flange sealing groove. A sealing ring or sealing gasket is installed in the flange sealing groove, and a fracturing wellhead is installed above the casing head (20). Bolts and nuts are used to connect the flange of the fracturing wellhead and the casing head (20). Tightening the bolts and nuts will cause the clamping force to press the sealing ring or sealing gasket to achieve a seal. The fracturing truck is connected to the fracturing wellhead, and pressure is delivered into the well through the inner casing (50) to carry out fracturing operations. After the fracturing operation is completed, remove the bolts and nuts to separate the flange of the casing head (20) from the fracturing wellhead. Remove the fracturing wellhead, take out the gasket or sealing ring from the flange sealing groove, take out the sealing assembly (30) from the sealing groove (212), switch the connecting unit (41) of the suspension assembly (40) from the suspended state to the released state through the telescopic drive mechanism (42), remove the connecting parts between the casing head (20) and the support plate (10), and lift the casing head (20) from above the support plate (10). A sealing cover is welded between the outer sleeve (60) and the inner sleeve (50) to seal the annular gap between the outer sleeve (60) and the inner sleeve (50).

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