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CN-121993077-A - Self-locking mechanism and casing head for petroleum wellhead

CN121993077ACN 121993077 ACN121993077 ACN 121993077ACN-121993077-A

Abstract

The invention relates to the technical field of casing heads, and discloses a self-locking mechanism and a casing head for an oil wellhead, comprising a primary casing head body, a secondary casing head body and a self-locking unit, wherein the secondary casing head body is arranged at the upper part of the primary casing head body, the self-locking unit is arranged at the upper end of the primary casing head body, is triggered when the secondary casing head body is mounted on the primary casing head body, and locks the secondary casing head body. According to the self-locking mechanism and the casing head for the petroleum wellhead, the self-locking unit is arranged between the primary casing head body and the secondary casing head body, when the secondary casing head body is arranged on the primary casing head body, the rack is extruded to move downwards, the rack pushes the sleeve to rotate, so that the lock pin is pushed to move and lock, and the lock pin is inserted into the clamping groove of the secondary casing head body, so that the secondary casing head body and the primary casing head body are fixed.

Inventors

  • ZHU CHENGJIANG
  • LIU ENMING
  • DING JIE

Assignees

  • 盐城市煜洋石油机械有限公司

Dates

Publication Date
20260508
Application Date
20260121

Claims (10)

  1. 1. The utility model provides a self-locking mechanism, its characterized in that, including one-level casing head body (1), second grade casing head body (2) and from locking unit (3), second grade casing head body (2) set up in one-level casing head body (1) upper portion, and from locking unit (3) set up in one-level casing head body (1) upper end, trigger when second grade casing head body (2) are installed on one-level casing head body (1) to with second grade casing head body (2) locking.
  2. 2. The self-locking mechanism according to claim 1, wherein the self-locking unit (3) comprises a sleeve (4) rotatably arranged on the side wall of the primary casing head body (1), a lock pin (5) is arranged in the sleeve (4), and the lock pin (5) moves radially along the primary casing head body (1); an annular clamping groove (6) is formed in the outer circumferential surface of the lower end of the second-stage casing head body (2), and one end of the lock pin (5) is clamped with the clamping groove (6).
  3. 3. A self-locking mechanism according to claim 2, wherein the self-locking unit (3) is provided in plurality along the circumferential direction of the primary casing head body (1).
  4. 4. The self-locking mechanism according to claim 2, wherein a through groove (7) is formed in the side wall of the sleeve (4), the side wall of the through groove (7) is a spiral surface (8), a limit groove (9) is formed in one end, close to the center of the primary casing head body (1), of the through groove (7), and the side wall of the limit groove (9) is perpendicular to the axis of the sleeve (4); The outer circumferential surface of the lock pin (5) is provided with a pin (10), and the pin (10) is slidably arranged in the through groove (7) and the limit groove (9).
  5. 5. The self-locking mechanism according to claim 4, wherein a gear (11) is provided at one end of the circumferential surface of the sleeve (4) away from the center of the primary casing head body (1); An annular groove (12) is formed in the upper end face of the primary casing head body (1), a groove (13) is formed in the bottom of the annular groove (12), a rack (14) is arranged in the groove (13) in a sliding mode, and the rack (14) is meshed with the gear (11).
  6. 6. The self-locking mechanism according to claim 5, wherein a first spring (15) is arranged in the groove (13), the upper end of the first spring (15) is connected with the lower end of the rack (14), and the lower end of the first spring (15) is connected with the bottom surface of the groove (13).
  7. 7. A self-locking mechanism according to claim 5, characterised in that a gear ring (16) is arranged in the annular recess (12) at a distance from the recess (13), the gear ring (16) being arranged in engagement with the gear wheel (11).
  8. 8. The self-locking mechanism according to claim 7, wherein an axial groove (17) arranged along the axial direction is formed in the outer circumferential surface of the lock pin (5), a limiting hole (18) is formed in the side wall of the primary casing head body (1), a limiting block (19) is arranged in the limiting hole (18), and the axial groove (17) is connected with the limiting block (19) in a matched mode.
  9. 9. The self-locking mechanism according to claim 8, wherein an avoidance groove (20) is formed in a position, corresponding to the rack (14), on the lower end face of the secondary casing head body (2), a plurality of second springs (21) are arranged on the bottom face of the avoidance groove (20) in an array mode, an annular pressing plate (22) is arranged in the avoidance groove (20) in a sliding mode, and one end, deviating from the bottom face of the avoidance groove (20), of each second spring (21) is connected with the annular pressing plate (22).
  10. 10. A casing head for a petroleum wellhead, comprising a self-locking mechanism according to any one of claims 1 to 9.

Description

Self-locking mechanism and casing head for petroleum wellhead Technical Field The invention relates to the technical field of casing heads, in particular to a self-locking mechanism and a casing head for an oil wellhead. Background The petroleum wellhead refers to the installation position of a device for controlling and guiding underground oil, gas and water fluid exploitation on the ground of an oil well, and is a key node for connecting the oil well with ground facilities, wherein a casing head is the lowest end part of the wellhead and is used for hanging a casing and sealing the wellhead to prevent stratum fluid leakage, and the casing head is connected with the casing of different layers. The casing head is one of core components of the well drilling wellhead device, is mainly used for fixing a wellhead structure and bearing multiple functions, is used as a key pivot for connecting a downhole casing string and surface equipment, is used for suspending the weight of each layer of casing except a surface casing, and is used for preventing pressure channeling through sealing an annular space of the casing, so that well control safety is ensured. The casing head provides the installation base for the blowout preventer during the drilling phase, and transitions to the connection of the tubing head and the tree during the production phase. Patent document CN113107412B discloses a pressure-resistant corrosion-resistant multi-stage casing head capable of exchanging different types of hangers, which consists of a base, a multi-stage casing head four-way joint, mandrel type casing hangers of different specifications, slip type casing hangers, and matched sealing collars, wing valves, threaded flanges, pressure gauge assemblies, threaded connectors and sealing elements. The central hole, BT sealing ring and grease injection valve below the sleeve head four-way joint of each stage above the lower stage can seal the extension neck above the mandrel sleeve hanger of the next stage, and the upper end of the sleeve clamped by the slip sleeve hanger of the replacement can be sealed through the matched sealing collar. In addition, the nonmetallic materials in the sealing piece are fluororubber or high-saturation hydrogenated nitrile rubber. So that the method is more suitable for being used in complex well conditions and wells with high pressure, high corrosion and high temperature difference. Among the multistage casing heads of prior art, the bolted connection is used to adjacent two-stage casing head, and installation and dismantlement are inconvenient, waste time and energy, have increased the time of installation and dismantlement casing head, influence work efficiency. Therefore, it is necessary to provide a self-locking mechanism and a casing head for a petroleum wellhead to solve the problems in the prior art. Disclosure of Invention In the summary, a series of concepts in a simplified form are introduced, which will be further described in detail in the detailed description. The summary of the invention is not intended to define the key features and essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. In order to solve the problems, the invention provides a self-locking mechanism which comprises a primary casing head body, a secondary casing head body and a self-locking unit, wherein the secondary casing head body is arranged at the upper part of the primary casing head body, the self-locking unit is arranged at the upper end of the primary casing head body, and the self-locking unit is triggered when the secondary casing head body is installed on the primary casing head body and locks the secondary casing head body. Preferably, the self-locking unit comprises a sleeve rotatably arranged on the side wall of the primary casing head body, and a lock pin is arranged in the sleeve and moves along the radial direction of the primary casing head body; An annular clamping groove is formed in the outer circumferential surface of the lower end of the second-stage casing head body, and one end of the lock pin is clamped with the clamping groove. Preferably, the self-locking unit is provided in plurality along the circumferential direction of the primary casing head body. Preferably, the side wall of the sleeve is provided with a through groove, the side wall of the through groove is a spiral surface, one end of the through groove, which is close to the center of the primary casing head body, is provided with a limit groove, and the side wall of the limit groove is perpendicular to the axis of the sleeve; the outer circumference of the lock pin is provided with a pin which is arranged in the through groove and the limit groove in a sliding way. Preferably, a gear is arranged at one end, far away from the center of the primary casing head body, of the circumferential surface of the sleeve; an annular groove is formed in the upper