Reusable casing head device and fracturing construction method

Abstract

The invention belongs to the technical field of casing heads for well drilling, and particularly provides a reusable casing head device and a fracturing construction method. A reusable casing head device comprises a supporting plate, a casing head, a sealing assembly and a hanging assembly. The supporting plate is connected with the outer-layer casing, the casing head is arranged on the periphery of the inner-layer casing in a sleeving mode, the hanging assembly comprises a plurality of connecting units arranged in the mounting cavity, and the telescopic driving mechanism can drive the connecting units to synchronously move in the radial direction to achieve clamping and releasing of the inner-layer casing. The casing head and the supporting plate are detachably connected, sealing between the casing head and the inner-layer casing is achieved through the sealing assembly, the risk of leakage of a well mouth in the fracturing process is eliminated, and the sealing performance requirement of well mouth fracturing construction can be met. And meanwhile, the inner-layer casing pipe is clamped or released through the suspension assembly with the switchable state, so that the casing pipe head can be detached for repeated use after fracturing is finished, and the drilling construction cost is reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of casing heads for drilling, and more specifically, relates to a reusable casing head device and a fracturing construction method. Background Art

[0002] A casing head is a connection device installed at the wellhead. Its function is to connect the casing below and achieve a seal between the layers of casing. In actual production, for wellheads with low or no pressure during drilling, due to the lower sealing requirements, a conventional casing head can be installed. Instead, a simple casing head can be welded between the inner and outer layers of casing using an annular steel plate, thereby reducing equipment costs.

[0003] However, when construction companies face the challenge of performing fracturing operations at wellheads with little or no pressure, the high internal pressure inside the casing during fracturing makes it difficult for simple casing heads made of annular steel plates to withstand the pressure. These heads experience significant vibration during fracturing, which can lead to stress fatigue. Furthermore, there is a risk of leakage at the connections and welds of the annular steel plates. Therefore, to prevent vibration and leakage, conventional casing heads must be installed, which fails to achieve the desired effect of reducing equipment costs. Summary of the Invention

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

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

[0006] In a first aspect, the present application provides a reusable casing head device, comprising:

[0007] A support plate is arranged around the outer circumference of the outer casing;

[0008] a casing head, disposed above the support plate and detachably connected to the support plate, the casing head having a vertically extending installation cavity for allowing the inner casing to pass through, and a sealing groove formed on the upper surface of the casing head surrounding the top opening of the installation cavity;

[0009] a sealing assembly, disposed in the sealing groove, for sealing the contact surface between the casing head and the inner casing; and

[0010] The suspension assembly includes multiple connection units and a telescopic drive mechanism. The multiple connection units are arranged in the installation cavity around the inner sleeve. The connection units have a suspension state connected to the inner sleeve and a release state separated from the inner sleeve. The telescopic drive mechanism is used to drive the multiple connection units to move synchronously along the radial direction of the inner sleeve so that the connection units can switch between the suspension state and the release state.

[0011] In a possible implementation, the casing head includes:

[0012] A first body is provided above the support plate and forms the installation cavity, wherein a side wall of the installation cavity is provided with a connection hole penetrating the wall thickness of the first body, and the connection hole corresponds to the connection unit one by one; and

[0013] The second body is arranged around the outer circumference of the first body, and the telescopic drive mechanism is arranged on the second body. The suspension assembly also includes a force transmission rod, which is slidably and sealedly matched 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 a possible implementation, a plurality of sliding grooves are formed on the top wall of the installation cavity, the sliding grooves corresponding to the connection units one by one, the sliding grooves extending radially along the inner sleeve, and opposite side walls of the sliding grooves respectively extending into the grooves to form support portions;

[0015] The connecting unit includes a sliding portion that is slidably matched with the sliding groove, and a connecting portion connected to the inner sleeve, and the sliding portion is located above the supporting portion.

[0016] In a possible implementation, the telescopic drive mechanism includes a plurality of electric telescopic rods arranged at intervals along the circumference of the inner sleeve, and the telescopic ends of the electric telescopic rods are arranged along the radial direction of the inner sleeve and connected to the corresponding force transmission rods.

[0017] In a possible implementation, a stop portion is formed around the circumference of the force transmission rod at one end away from the connection unit, and the telescopic drive mechanism includes:

[0018] a drive ring coaxially sleeved on the outer circumference of the first body and rotatably engaged with the second body; an inner sidewall of the drive ring is provided with a plurality of drive portions spaced apart along its circumference, the drive portions corresponding one to one with the force transmission rods; the drive portions gradually tilt toward 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; an end of the force transmission rod away from the connecting unit abuts against the guide surface;

[0019] a plurality of elastic elements, each corresponding to the force transmission rod, one end of the elastic element abutting against the stop portion and the other end abutting against the first body, the elastic element being configured with a pre-tightening force for causing the force transmission rod to move toward the drive ring; and

[0020] The rotary driving member is provided on the second body and is used for driving the driving member to rotate around its own central axis.

[0021] In one possible implementation, an annular limiting boss is formed on the outer wall of the inner sleeve, and a side of the connecting unit used to fit 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 a possible implementation, the connecting unit is further provided with an anti-fall wheel on a side adjacent to the inner sleeve, the anti-fall wheel is eccentrically rotatably connected to the connecting unit, and the outer periphery of the anti-fall wheel is covered with a rubber material layer;

[0023] The anti-fall wheel is defined as having a large diameter side and a small diameter side, the distance between the outer peripheral surface of the small diameter side and the axis center is smaller than the distance between the outer peripheral surface of the large diameter side and the axis center, and in the initial state, the small diameter side faces the inner sleeve; the rotating shaft of the anti-fall wheel is connected to a torsion spring, and the torsion spring is configured with a pre-tightening force to reset the anti-fall wheel to the initial state.

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

[0025] Two mounting rings are arranged in the sealing groove at intervals, and the mounting rings are provided with a plurality of mounting holes along their circumferential directions;

[0026] an elastic sealing element, which is annular and disposed between the two mounting rings, the elastic sealing element being provided with avoidance holes corresponding to the upper and lower sides of the mounting holes; and

[0027] A plurality of fasteners are corresponding to the mounting holes one by one. The fasteners are passed through the upper mounting holes and threadedly engaged with the lower mounting holes.

[0028] In one possible implementation, an extrusion boss is provided on one side of the mounting ring for contacting the elastic sealing element. The extrusion bosses are two in number and are concentrically arranged, with the two extrusion bosses being located on either side of the mounting hole, respectively. The extrusion bosses have a trapezoidal cross-section, with the long side of the trapezoid being adjacent to the mounting ring and the short side of the trapezoid being adjacent to the elastic sealing element.

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

[0030] Compared with the prior art, the reusable casing head device provided by this application has the following beneficial effects:

[0031] The present application provides a reusable casing head device including a support plate, a casing head, a sealing assembly and a suspension assembly. When in use, the support plate is connected to the outer casing, the casing head is detachably connected to the support plate and is sleeved on the outer periphery of the inner casing, the suspension assembly includes a plurality of connection units arranged in the installation cavity, and the telescopic drive mechanism can drive the plurality of connection units to move synchronously in the radial direction to achieve clamping and releasing of the inner casing. During the fracturing construction, the connection unit is in a suspended state and can clamp the inner casing. The sealing assembly can seal the contact surface between the casing head and the inner casing to avoid leakage due to excessive pressure during the fracturing, thereby ensuring the smooth progress of the fracturing construction. After the fracturing is completed, the telescopic drive mechanism can be used to control the connection unit to switch from the suspended state to the released state, so that the casing head can be removed from the inner casing to achieve reusability.

[0032] This application provides a support plate around the outer casing, with the casing head and support plate detachably connected. A sealing assembly is used to achieve a seal between the casing head and the inner casing, eliminating the risk of wellhead leakage during fracturing and meeting the sealing requirements of 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, reducing drilling construction costs.

[0033] In a second aspect, the present application provides a fracturing construction method, which uses a reusable casing head device described in any of the above implementations, including the following steps:

[0034] Cut and grind the edges of the inner and outer casings so that the top of the outer casing is lower than the top of the inner casing;

[0035] Fixing and connecting the support plate on the outer casing;

[0036] Assemble the casing head and the hanging assembly together, hang the casing head on the support plate and connect and fix it to the support plate. Initially, the connecting unit of the hanging assembly is in the released state, so that the upper end of the inner casing passes through the top opening of the installation cavity. Then, the connecting unit of the hanging assembly is switched to the hanging state by the telescopic driving mechanism to clamp the inner casing.

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

[0038] An annular flange sealing groove is provided on the upper surface of the casing head, a sealing ring or a sealing gasket is installed in the flange sealing groove, and a fracturing wellhead is installed above the casing head;

[0039] Use bolts and nuts to connect the fracturing wellhead and the flange of the casing head together, tighten the bolts and nuts so that the clamping force presses the sealing ring or sealing gasket to achieve sealing;

[0040] Connect the fracturing truck through the fracturing wellhead and transmit pressure into the well through the inner casing to perform fracturing operations;

[0041] After the fracturing operation is completed, the bolts and nuts are removed to separate the flange of the casing head and the fracturing wellhead from each other, the fracturing wellhead is removed, the sealing gasket or sealing ring is taken out from the flange sealing groove, the sealing assembly is taken out from the sealing groove, the connecting unit of the suspension assembly is switched to the released state by the telescopic drive mechanism, the connecting piece between the casing head and the support plate is removed, and the casing head is lifted from above the support plate;

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

[0043] The fracturing construction method provided in this application is suitable for fracturing construction on low-pressure or no-pressure wellheads, and has the same technical effect as the above-mentioned reusable casing head device, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0045] Figure 1 A three-dimensional structural diagram of a reusable casing head device provided in Example 1 of the present application;

[0046] Figure 2 This is a longitudinal stereoscopic cross-sectional view of the connecting unit in the first embodiment of the present application when it is in a suspended state;

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

[0048] Figure 4 A three-dimensional cross-sectional view in the horizontal direction of a reusable casing head device provided in Example 1 of the present application;

[0049] Figure 5 This is a partial three-dimensional cross-sectional view of the connecting unit in the first embodiment of the present application when it is in a released state;

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

[0051] Figure 7 A three-dimensional structural diagram of a reusable casing head device provided in Example 2 of the present application;

[0052] Figure 8 A longitudinal cross-sectional view of a reusable cannula head device provided in Example 2 of the present application;

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

[0054] Figure 10 This is the exploded view of the seal assembly;

[0055] Figure 11 for Figure 10 A partial enlarged view of part B in the middle;

[0056] Description of reference numerals:

[0057] 10. Support plate; 20. Casing 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 portion; 412. Connecting portion; 42. Telescopic drive mechanism; 421. Drive ring; 4211. Drive portion; 4212. Guide surface; 422. Elastic element; 423. Rotary drive member; 43. Force transmission rod; 431. Stop portion; 44. Anti-fall wheel; 441. Large diameter side; 442. Small diameter side; 50. Inner casing; 51. Limiting boss; 60. Outer casing. DETAILED DESCRIPTION

[0058] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0059] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0060] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and 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, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" or "several" means two or more, unless otherwise specifically defined.

[0062] Unless defined otherwise, 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 belongs.

[0063] Please also refer to Figures 1 to 11 , the following describes a reusable casing head device and fracturing construction method provided by the present application.

[0064] The present application provides a reusable casing head device and a fracturing construction method suitable for low-pressure or no-pressure drilling fracturing construction, which can be dismantled and reused after the fracturing is completed, thereby reducing the drilling construction cost.

[0065] For details, please refer to Figures 1 to 5 , Embodiment 1 of the present application provides a reusable casing head device, including a support plate 10, a casing head 20, a sealing assembly 30 and a suspension assembly 40. The support plate 10 is arranged around the outer periphery of the outer sleeve 60; the sleeve head 20 is arranged above the support plate 10 and is detachably connected to the support plate 10. The sleeve head 20 has an installation cavity 211 that runs vertically through, and the installation cavity 211 is used 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; the sealing assembly 30 is arranged 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 a plurality of connection units 41 and a telescopic drive mechanism 42. The plurality of connection units 41 are arranged in the installation cavity 211 around the inner sleeve 50. The connection unit 41 has a suspension state connected to the inner sleeve 50 and a release state separated from the inner sleeve 50. The telescopic drive mechanism 42 is used to drive the plurality of connection units 41 to move synchronously along the radial direction of the inner sleeve 50 so that the connection unit 41 switches between the suspension state and the release state.

[0066] Compared with the prior art, the reusable casing head device provided in the first embodiment of the present application has the following beneficial effects:

[0067] A reusable casing head device provided in Example 1 of the present application includes a support plate 10, a casing head 20, a sealing assembly 30, and a suspension assembly 40. When 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 is sleeved on the outer periphery of the inner casing 50. The suspension assembly 40 includes a plurality of connection units 41 arranged in the installation cavity 211. The telescopic drive mechanism 42 can drive the plurality of connection units 41 to move synchronously in the radial direction to achieve clamping and releasing of the inner casing 50. During fracturing operation, the connection units 41 are in a suspended state and can clamp the inner casing 50. The sealing assembly 30 can seal the contact surface between the casing head 20 and the inner casing 50 to prevent leakage due to excessive pressure during fracturing, thereby ensuring the smooth progress of the fracturing operation. After fracturing is completed, the telescopic drive mechanism 42 can control the connection units 41 to switch from the suspended state to the released state, so that the casing head 20 can be removed from the inner casing 50, achieving reusability.

[0068] In the first embodiment of the present application, a support plate 10 is provided on the outer periphery of the outer casing 60, and the casing head 20 and the support plate 10 are detachably connected, and a seal is achieved between the casing head 20 and the inner casing 50 by a sealing assembly 30, thereby eliminating the risk of leakage at the wellhead during the fracturing process and meeting the sealing requirements of the wellhead fracturing construction. At the same time, the present application also achieves the clamping or release of the inner casing 50 by a suspension assembly 40 with a switchable state, so that the casing head 20 can be removed and reused after the fracturing is completed, thereby reducing the cost of drilling construction compared to installing a conventional casing head. After the fracturing is completed, an annular steel plate can be welded between the inner casing 50 and the outer casing 60 to serve as a simple casing head. The dismantled casing head device can be reused in different drilling constructions.

[0069] like Figure 6 As shown, before construction, the outer casing 60 needs to be cut and ground. The top of the inner casing 50 should be higher than the outer casing 60, and the edge should be smooth and burr-free, and the outer surface should be free of oil stains and rust.

[0070] After grinding is complete, the support plate 10 is connected and fixed to the outer casing 60. The support plate 10 can be an annular plate that fits around the outer circumference of the outer casing 60. The support plate 10 is made of steel and can be fixed to the outer casing 60 by welding, screwing, or other methods. The support plate 10 can be provided with a flange surface for removable connection to the casing head 20 via bolts or other fasteners. After fracturing is complete, the support plate 10 can be removed or retained as needed.

[0071] The cannula head 20 has an internal mounting cavity 211 extending vertically therethrough. After installation, the bottom surface of the cannula head 20 contacts the upper surface of the support plate 10, and the inner cannula 50 is inserted into the mounting cavity 211. The mounting cavity 211 can be annular or in other shapes, and the sealing assembly 30 is disposed at the top opening of the mounting cavity 211 to achieve a seal.

[0072] To ensure a tight seal between the support plate 10 and the casing head 20 during fracturing, a gasket or sealant can be placed between the support plate 10 and the casing head 20. The gasket and the sealing assembly 30 can be metal or rubber sealing elements, and can be a single component or an assembly of multiple parts. The gasket and sealing assembly 30 can be commercially available sealing products, with no specific restrictions on their type or model, as long as they meet the sealing requirements during fracturing.

[0073] The suspension assembly 40 includes multiple connection units 41 and a telescopic drive mechanism 42 that drives the multiple connection units 41 to move synchronously. The multiple connection units 41 are arranged in a circular array around the outer periphery of the inner casing 50 and are used to support the inner casing 50 during fracturing operations. The connection units 41 can be blocks or other shaped components that can be connected to the inner casing 50. When the multiple connection units 41 are in a suspended state, they can clamp the inner casing 50. When the connection units 41 are in a released state, they separate from the inner casing 50.

[0074] The telescopic driving mechanism 42 can specifically be a power component such as a telescopic cylinder, an electric telescopic rod, etc., which can drive the connecting unit 41 to achieve radial movement.

[0075] Since the casing head 20 is mostly installed on the inner casing 50 by crane, in order to facilitate lifting, a lifting ring can be provided at the upper end of the casing head 20, which is fixed or detachable and is used to connect a lifting rope. In addition to the above-mentioned hanging state and release state, the connecting unit 41 also has a positioning state for guiding the installation of the casing head 20. Specifically, in order to improve the installation accuracy of the casing head 20, during the process of lowering the casing head 20 to the support plate 10, the connecting unit 41 can be controlled by the telescopic drive mechanism 42 to move toward the inner casing 50, so that the connecting unit 41 is in contact with the outer wall of the inner casing 50 or separated by a small distance. At this time, the connecting unit 41 is in a positioning state. In the positioning state, multiple connecting units 41 can achieve concentric alignment of the casing head 20 and the inner casing 50 during the descent of the casing head 20, so that the installation and positioning of the casing head 20 and the inner casing 50 can be achieved more conveniently, quickly and accurately.

[0076] The suspension assembly 40 in the first embodiment can be used for clamping and suspending the inner casing 50 during fracturing construction, and can also be used for aligning and positioning the casing head 20 during the hanging process, thus achieving two goals at one stroke.

[0077] Further, see Figure 1 、 Figure 2 、 Figure 3 and Figure 5 The casing head 20 includes a first body 21 and a second body 22. The first body 21 is arranged above the support plate 10 and forms an installation cavity 211. The side wall of the installation cavity 211 is provided with a connecting hole that penetrates the wall thickness of the first body 21, and the connecting hole corresponds to the connecting unit 41 one by one; the second body 22 is arranged around the outer periphery of the first body 21, and the telescopic drive mechanism 42 is arranged on the second body 22. The suspension assembly 40 also includes a force transmission rod 43, which is slidably and sealedly matched 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 and second bodies 21, 22 can be integrally connected by welding or removably connected using bolts or other fasteners. The first body 21 forms a mounting cavity 211. The first body 21 seals against the support plate 10 at the bottom and seals against the inner casing 50 at the top via a sealing assembly 30, ensuring no leakage 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 first embodiment, the telescopic drive mechanism 42 is positioned outside the first body 21, making it easier to access and maintain, and improving practicality. The first and second bodies 21, 22 can be connected and secured by welding or bolting.

[0080] The force transmission rod 43 can be a steel component in a circular, square or other shapes. The force transmission rod 43 and the connecting hole should have a high matching accuracy, and a sealing ring should be provided to achieve sealing.

[0081] Further, see Figure 3 and Figure 5In order to improve the load-bearing capacity of the connecting unit 41, a plurality of sliding grooves 213 are provided on the top wall of the installation cavity 211. The sliding grooves 213 correspond to the connecting units 41 one by one. The sliding grooves 213 extend along the radial direction of the inner sleeve 50. The opposite side walls of the sliding grooves 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 connected 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 portion is a protrusion formed on the side wall of the slide groove 213, which can support the sliding portion 411 of the connecting unit 41, improve the 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, thereby meeting the requirements of reusability.

[0083] There is no restriction on the specific structural form of the telescopic drive mechanism 42. For example, the telescopic drive mechanism 42 may include a plurality of electric telescopic rods arranged at circumferential intervals along the inner sleeve 50. The telescopic ends of the electric telescopic rods are connected to the force transmission rods 43. The plurality of electric telescopic rods extend or contract synchronously, driving the plurality of force transmission rods 43 and the connecting unit 41 to move synchronously.

[0084] Or, as Figure 4 and Figure 8 As shown, in the first or second embodiment, a stopper 431 is formed around the circumference of the force transmission rod 43 at one end away from the connection unit 41, and 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 circumference of the first body 21 and is rotatably engaged with the second body 22. The inner side wall of the drive ring 421 is provided with a plurality of drive portions 4211 spaced along its own circumference. The drive portions 4211 correspond to the force transmission rods 43 one by one. The drive portions 4211 gradually tilt toward 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 connection unit 41. 1 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 portion 4211; a plurality of elastic elements 422 are provided on the force transmission rod 43 in a one-to-one correspondence, one end of the elastic element 422 abuts against the stop portion 431, and the other end abuts against the first body 21, and the elastic element 422 is configured with a pre-tightening force that causes the force transmission rod 43 to move toward the driving ring 421; a rotary driving 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 has a plurality of drive parts 4211 on its inner wall. The plurality of drive parts 4211 correspond to a plurality of force transmission rods 43 one by one. The end of each force transmission rod 43 abuts against the guide surface 4212 of the drive part 4211. Figure 8 For example, when the drive ring 421 rotates counterclockwise, the guide surface 4212 can push the force transmission rod 43 to expand and contract inward, overcoming the preload force 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 force, the elastic element 422 pushes the force transmission rod 43 to return, moving the connecting unit 41 away from the inner sleeve 50. To reduce resistance, the end of the force transmission rod 43 that contacts the guide surface 4212 can be designed as a spherical surface.

[0086] The rotary driving member 423 can be a power device capable of outputting rotary motion, such as an electric motor or a hydraulic motor. The output shaft of the rotary driving member 423 can drive the driving ring 421 to rotate by gear transmission, chain transmission, or the like.

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

[0088] Multiple connecting units 41 are assembled to form an annular support ring. The limiting boss 51 can be machined from the inner casing 50, specifically by lathing it before inserting the final inner casing 50, or it can be an existing pipe clamp. The limiting boss 51 serves to facilitate support of the connecting units 41.

[0089] See also Figure 7 and Figure 8 , which is different from the above-mentioned embodiment 1, the connection unit 41 in the second embodiment is further provided with an anti-fall wheel 44 on the side adjacent to the inner sleeve 50, and the anti-fall wheel 44 is eccentrically connected to the connection unit 41, and the outer periphery of the anti-fall wheel 44 is covered with a rubber material layer; the outer periphery of the anti-fall wheel 44 is defined as a large diameter side 441 and a small diameter side 442, and the angles between the large diameter side 441 and the small diameter side 442 are 180 degrees respectively, and the distance between the outer periphery of the small diameter side 442 and the axis is smaller than the distance between the outer periphery of the large diameter side 441 and the axis. In the initial state (such as Figure 8(as shown), with the smaller diameter side 442 facing the inner casing 50. A torsion spring is connected to the rotating shaft of the anti-fall wheel 44. The torsion spring is configured with a preload force to reset the anti-fall wheel 44 to its initial state. The installation of a torsion spring on the rotating shaft for resetting wheel components is a common arrangement in the art, and the specific installation method, shape, and specifications of the torsion spring are not specifically limited.

[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, and 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 tends to rotate from the small diameter side 442 to the large diameter side 441. In the process of rotating toward 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 the first embodiment, in order to make the connecting unit 41 support the inner sleeve 50 more stably, it is necessary to additionally process the inner sleeve 50 to obtain a limiting boss 51, which increases the workload of the construction party. In order to facilitate construction, the second embodiment adopts an eccentrically arranged anti-fall wheel 44 to contact the inner sleeve 50. When the inner sleeve 50 has a tendency to fall, the friction generated by the anti-fall wheel 44 increases accordingly, thereby overcoming the falling force and keeping the inner sleeve 50 in its original position. With this arrangement, there is no need to additionally provide a limiting boss 51 on the inner sleeve 50, which is more convenient during construction.

[0092] See also Figure 9 、 Figure 10 and Figure 11 In the first or second embodiment, the sealing assembly 30 includes a mounting ring 31, an elastic sealing element 32 and a fastener 33. The two mounting rings 31 are arranged in the sealing groove 212 with an upper and lower interval. The mounting ring 31 has multiple mounting holes along its own circumferential direction; the elastic sealing element 32 is annular and is arranged between the two mounting rings 31. The elastic sealing element 32 has avoidance holes corresponding to the upper and lower mounting holes; multiple fasteners 33 correspond to the mounting holes one by one, and the fasteners 33 are passed through the upper mounting hole and threadedly engaged with the lower mounting hole.

[0093] In this embodiment, two mounting rings 31 are disposed in an upper and lower position relative to each other. The mounting hole of the upper mounting ring 31 is a plain hole, while the mounting hole of the lower mounting ring 31 is a threaded hole. During use, the mounting rings 31, elastic sealing element 32, and fastener 33 are first assembled together, without tightening the fastener 33. The assembled sealing assembly 30 is then placed into the sealing groove 212, and the fastener 33 is gradually tightened. During the tightening process of the fastener 33, the two mounting rings 31 approach each other, squeezing the elastic sealing element 32, causing it to expand to both sides, thereby sealing the contact surface between the inner sleeve 50 and the sleeve head 20.

[0094] It's 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, otherwise the sealing effect will be affected. Specifically, the fasteners 33 should be tightened in a diagonal, clockwise direction, in stages. 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] See also Figure 9 Figure 10 and Figure 11 Furthermore, an extrusion boss 311 is provided on one side of the mounting ring 31 for fitting the elastic sealing element 32. There are two extrusion bosses 311, which are concentrically arranged. The two extrusion bosses 311 are respectively located on both sides of the mounting hole; the cross-section of the extrusion 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 surface and the lower surface of the elastic sealing element 32 are respectively provided with extrusion grooves 321 adapted to the extrusion boss 311.

[0096] During the tightening process of the fastener 33, the two mounting rings 31 approach each other under the clamping force of the fastener 33, and the extrusion boss 311 can squeeze the elastic sealing element 32, so that the elastic sealing element 32 spreads evenly to the periphery under the action of the clamping force, and seals 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 have good sealing performance when reused.

[0097] In a second aspect, the present application provides a fracturing construction method, which uses a reusable casing head device provided in the above-mentioned embodiment 1 or embodiment 2, including the following steps:

[0098] The outer sleeve 60 is cut and edge-grinded so that the top height of the outer sleeve 60 is lower than the top height of the inner sleeve 50 .

[0099] The support plate 10 is fixedly connected to the outer sleeve 60 , and can be fixed specifically by welding, bolt connection, or the like.

[0100] After the outer sleeve 60 and the 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 suspension rope through the suspension ring, use a crane to lift the sleeve head 20 onto the support plate 10, and then connect and fix the sleeve head 20 to the support plate 10. Initially, the connection unit 41 of the suspension assembly 40 is in a released state, allowing the upper end of the inner sleeve 50 to pass through the top opening of the installation cavity 211, and then the connection unit 41 of the suspension assembly 40 is switched to a suspended state by the telescopic drive mechanism 42 to clamp the inner sleeve 50.

[0101] The sealing assembly 30 is installed in the sealing groove 212 to seal between the inner casing 50 and the casing head 20 .

[0102] The inner casing 50 is connected to the output end of the fracturing truck, and the fracturing truck transmits pressure into the wellbore through the inner casing 50 to perform fracturing operations. Specifically, an annular flange sealing groove is opened on the upper surface of the casing head 20, and a sealing ring or sealing gasket is installed in the flange sealing groove. A fracturing wellhead is installed above the casing head 20. The fracturing wellhead and the flange of the casing head 20 are connected together using bolts and nuts. The bolts and nuts are tightened so that the clamping force compresses the sealing ring or sealing gasket to achieve sealing. The fracturing truck is connected through the fracturing wellhead, and pressure is transmitted into the wellbore through the inner casing 50 to perform fracturing operations.

[0103] Fracturing trucks are used to inject high-pressure, high-volume fracturing fluid into a well, breaking up the formation and squeezing proppant into the cracks, completing the fracturing operation. The specific structure and operation of the fracturing truck and fracturing wellhead are prior art and will not be detailed 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 then 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, and switch the connecting unit 41 of the suspension assembly 40 to the released state via the telescopic drive mechanism 42. Remove the connector between the casing head 20 and the support plate 10, and then lift the casing head 20 from above the support plate 10. To ensure that the casing head 20 can be lifted from above, the opening diameter of the installation cavity 211 should be larger than the outer diameter of the inner casing 50.

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

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

Claims

1. A reusable cannula head device, characterized in that: include: A support plate (10) is arranged around the outer periphery of the outer sleeve (60); a casing head (20) disposed above the support plate (10) and detachably connected to the support plate (10); the casing head (20) having a mounting cavity (211) for allowing the inner casing (50) to pass through; and a sealing groove (212) formed on the upper surface of the casing head (20) surrounding the top opening of the mounting cavity (211); a sealing assembly (30), disposed in the sealing groove (212), for sealing the contact surface between the casing head (20) and the inner casing (50); and The suspension assembly (40) includes a plurality of connection units (41) and a telescopic drive mechanism (42). The plurality of connection units (41) are arranged in the installation cavity (211) around the inner sleeve (50). The connection units (41) have a suspension state connected to the inner sleeve (50) and a release state separated from the inner sleeve (50). The telescopic drive mechanism (42) is used to drive the plurality of connection units (41) to move synchronously along the radial direction of the inner sleeve (50) so that the connection units (41) switch between the suspension state and the release state.

2. A reusable cannula head device according to claim 1, characterized in that: The casing head (20) comprises: A first body (21) is provided above the support plate (10) and forms the installation cavity (211), a side wall of the installation cavity (211) is provided with a connection hole penetrating the wall thickness of the first body (21), and the connection hole corresponds to the connection unit (41) one by one; and The second body (22) is coaxially connected to the first body (21), and the telescopic drive mechanism (42) is provided on the second body (22). The suspension assembly (40) further includes a force transmission rod (43), and the force transmission rod (43) is in sliding and sealing cooperation 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).

3. A reusable cannula head device according to claim 1 or 2, characterized in that: The top wall of the installation cavity (211) is provided with a plurality of slide grooves (213), the slide grooves (213) corresponding to the connection units (41) one by one, the slide grooves (213) extending along the radial direction of the inner sleeve (50), and the two opposite side walls of the slide groove (213) extending into the groove to form support portions; The connecting unit (41) comprises a sliding portion (411) that is slidably matched with the sliding groove (213), and a connecting portion (412) that is connected to the inner sleeve (50), and the sliding portion (411) is located above the supporting portion.

4. A reusable cannula head device according to claim 2, characterized in that: The telescopic drive mechanism (42) comprises a plurality of electric telescopic rods arranged at intervals along the circumference of the inner sleeve (50), the telescopic ends of the electric telescopic rods being arranged along the radial direction of the inner sleeve (50) and connected to the corresponding force transmission rods (43).

5. A reusable cannula head device according to claim 2, characterized in that: The end of the force transmission rod (43) away from the connection unit (41) is formed with a stopper (431) around its circumference, and the telescopic driving mechanism (42) includes: A driving ring (421) is coaxially sleeved on the outer circumference of the first body (21) and rotatably engaged with the second body (22); a plurality of driving portions (4211) are provided on the inner side wall of the driving ring (421) at intervals along its own circumference, and the driving portions (4211) correspond one to one with the force transmission rods (43); the driving portions (4211) are gradually inclined toward the center of the driving ring (421) in the circumferential direction to form a guide surface (4212) with one end close to the center of the driving ring (421) and the other end close to the inner wall of the driving ring (421); and the end of the force transmission rod (43) away from the connecting unit (41) abuts against the guide surface (4212); a plurality of elastic elements (422) provided on the force transmission rod (43) in a one-to-one correspondence, one end of the elastic element (422) abutting against the stopper (431), and the other end abutting against the first body (21), and the elastic element (422) being configured with a pre-tightening force for causing the force transmission rod (43) to move toward the drive ring (421); and The rotary driving member (423) is provided on the second body (22) and is used to drive the driving ring (421) to rotate along its own central axis.

6. A reusable cannula head device according to claim 1, characterized in that: An annular limiting boss (51) is formed on the outer wall of the inner sleeve (50); when the connecting unit (41) is in the suspended state, the connecting unit (41) is supported below the limiting boss (51).

7. A reusable cannula head device according to claim 1 or 6, characterized in that: The connecting unit (41) is further provided with an anti-fall wheel (44) on one side adjacent to the inner sleeve (50), the anti-fall wheel (44) being eccentrically rotatably connected to the connecting unit (41), and the outer periphery of the anti-fall wheel (44) being covered with a rubber material layer; The anti-fall wheel (44) is defined as having a large diameter side (441) and a small diameter side (442), the distance between the outer peripheral surface of the small diameter side (442) and the axis center is smaller than the distance between the outer peripheral surface of the large diameter side (441) and the axis center, and in an initial state, the small diameter side (442) faces the inner sleeve (50); the rotating shaft of the anti-fall wheel (44) is connected to a torsion spring, and the torsion spring is configured with a preload force to reset the anti-fall wheel (44) to the initial state.

8. A reusable cannula head device according to claim 1, characterized in that: The sealing assembly (30) comprises: Two mounting rings (31) are arranged in the sealing groove (212) at intervals in the upper and lower parts, and the mounting rings (31) are provided with a plurality of mounting holes along their circumferential direction; An elastic sealing element (32) is annular and is disposed between the two mounting rings (31), wherein the elastic sealing element (32) is provided with avoidance holes corresponding to the upper and lower mounting holes; and A plurality of fasteners (33) correspond to the mounting holes one by one, and the fasteners (33) are passed through the upper mounting holes and threadedly matched with the lower mounting holes.

9. A reusable cannula head device according to claim 8, characterized in that: The mounting ring (31) is provided with an extrusion boss (311) on one side thereof for contacting the elastic sealing element (32). The number of the extrusion bosses (311) is two and they are concentrically arranged. The two extrusion bosses (311) are respectively located on both sides of the mounting hole. The cross section of the extrusion boss (311) is a trapezoid, the long side of the trapezoid is arranged adjacent to the mounting ring (31), and the short side of the trapezoid is arranged adjacent to the elastic sealing element (32). The upper surface and the lower surface of the elastic sealing element (32) are respectively provided with an extrusion groove (321), and the extrusion groove (321) is a trapezoidal groove adapted to the extrusion boss (311).

10. A fracturing construction method, characterized in that: A reusable casing head device according to any one of claims 1 to 9 is used, The following steps are involved: A support plate (10) is fixedly connected to the outer sleeve (60); Assemble the casing head (20) and the suspension assembly (40) together, hang the casing head (20) on the support plate (10) and connect and fix it to the support plate (10); initially, the connection unit (41) of the suspension assembly (40) is in a released state, so that the upper end of the inner casing (50) passes through the top opening of the installation cavity (211); then, the connection unit (41) of the suspension assembly (40) is switched to a suspended state by the telescopic drive mechanism (42) to clamp the inner casing (50); Installing the sealing assembly (30) into the sealing groove (212); An annular flange sealing groove is provided on the upper surface of the casing head (20), a sealing ring or a sealing gasket is installed in the flange sealing groove, and a fracturing wellhead is installed above the casing head (20); The fracturing wellhead and the flange of the casing head (20) are connected together using bolts and nuts, and the bolts and nuts are tightened so that the clamping force presses the sealing ring or sealing gasket to achieve sealing; Connecting a fracturing truck through the fracturing wellhead, transmitting pressure into the well through the inner casing (50) to perform fracturing operations; After the fracturing operation is completed, the bolts and nuts are removed to separate the flange of the casing head (20) and the fracturing wellhead from each other, the fracturing wellhead is removed, the sealing gasket or the sealing ring is taken out from the flange sealing groove, the sealing assembly (30) is taken out from the sealing groove (212), the connecting unit (41) of the suspension assembly (40) is switched from the suspension state to the release state through the telescopic drive mechanism (42), the connecting piece between the casing head (20) and the support plate (10) is removed, and the casing head (20) is suspended from above the support plate (10); A sealing cover plate 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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