A core shaft type hanger with locking mechanism for wellhead device

Abstract

A kind of core shaft hanger with locking mechanism for wellhead device is composed of hanger body, locking mechanism and two kinds of sealing elements.The hanger body is a main structural part of core shaft hanger with elongated neck, and locking mechanism composed of driving nut, ring wedge and spring ring is installed at the position of stud and groove in the upper part of hanger body to cooperate with the recess in the center step hole of tubing head or casing head four-way cross to lock; metal sealing assembly with three layers of inner and outer sealing wire is installed on the cylinder and stud body in the lower part of hanger body; a big elastic sealing ring resistant to ultra-high pressure is installed in the recess in the middle part of hanger body, and a elastic sealing ring resistant to ultra-high pressure is respectively installed in the two recesses in the upper part of hanger body.Therefore, a series of problems such as clumsiness, leakage and high price caused by using locking screw to fix hanger are avoided, and the hanger also has the advantages of easy and fast assembly, advanced and reliable sealing, etc.

Description

TECHNICAL FIELD

[0001] The present application relates to wellhead components of oil machinery and drilling equipment. BACKGROUND

[0002] At present, the tubing or casing hanger components used in various wellheads (including casing heads) at home and abroad are installed in the central hole of the tubing head cross or the casing head cross of the wellhead, and are fixed by locking screws with sealing assemblies uniformly distributed around the flange. Although the basic structure and fixing method of the existing tubing or casing hanger have a long history of use, there are still many unsatisfactory problems: first, it is not easy to process more than ten high-precision threaded radial stepped holes uniformly distributed around the flange of the tubing head or casing head cross, as well as the same number of complex locking screws and matching high-pressure resistant sealing assemblies; it requires a large amount of manpower and material resources, increasing production costs and product prices. Second, the locking screw holes with sealing assemblies uniformly distributed around the flange of the tubing head or casing head cross weaken the structural strength of the tubing head or casing head cross; in order to ensure the safety of the part under super-high pressure working conditions, the thickness of the flange has to be artificially increased, resulting in the bulkiness and waste of metal materials. Third, the sealing assemblies carried by the numerous uniformly distributed locking screws need to be urgently repaired as soon as one of them leaks to prevent safety accidents; it is inevitable to consume manpower and material resources to repair high-pressure or super-high pressure oil or gas extraction equipment, and the loss will be greater if a safety accident occurs. Therefore, it is necessary to study a new hanger fixing method. SUMMARY

[0003] The purpose of the present application is to design a core shaft type hanger with locking mechanism for wellhead, which can avoid the problems of using locking screws to fix the hanger, and further improve the quality and reliability of the wellhead.

[0004] The present application is composed of a hanger body, a locking mechanism and two kinds of sealing elements; its characteristic is that: the hanger body is a main structural part of the core shaft type hanger with an elongated neck, and a locking mechanism composed of a driving nut, an annular wedge and a spring ring is installed at the screw post and the groove in the upper part of the hanger body; a metal sealing assembly with three layers of internal and external sealing wires is installed on the cylindrical body and the screw post in the lower part of the hanger body; a super-high pressure resistant elastic sealing ring is installed in the groove in the middle part of the hanger body, and a super-high pressure resistant elastic sealing ring is installed in each of the two grooves in the upper part of the hanger body.

[0005] Further, the metal sealing assembly with three layers of internal and external sealing wires is composed of three layers of superimposed "eight" shaped cross-section metal sealing rings, a trapezoidal cross-section support ring, a round nut and a locking screw from top to bottom.

[0006] Further, the super-high pressure-resistant large elastic sealing ring and the elastic sealing ring have parallel straight lines on the upper and lower sections, a circular-arc-shaped groove on the inner edge, and a circular-arc-shaped protrusion on the outer edge; the main body material is FKM fluororubber or HNBR high-saturation hydrogenated butyronitrile rubber; and a stainless steel spring ring is inlaid at each shoulder of the protrusion end.

[0007] The locking mechanism composed of the driving nut, the annular wedge and the spring ring is used for fixing, so that the cost and price problems caused by the high-precision radial stepped holes with threads distributed on the periphery of the flange of the tubing head or the casing head cross, the complicated locking screws and the matched high-pressure-resistant sealing assembly are avoided; the problems of increasing the thickness and the bulk of the flange due to the weakening of the structural strength of the tubing head or the casing head cross caused by the numerous locking screw holes are avoided; the oil and gas leakage accidents caused by the sealing assembly of the numerous locking screws are avoided, and the like. In addition, the metal sealing assembly with three inner and outer sealing lines is used to replace the metal sealing assembly with one or two sealing lines, so that the reliability of the metal sealing is further improved; the elastic sealing ring with the new structure of the composite material is used to replace the commonly used O-shaped sealing ring, and the super-high pressure-resistant performance of the elastic sealing ring is significantly improved, so that the overall quality and performance of the wellhead device are further improved. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 It is a schematic view of the overall structure of the application;

[0009] Figure 2 It is a schematic view of the structure of the application installed in the tubing head or the casing head cross of the wellhead device;

[0010] Figure 3 It is Figure 1 It is an enlarged schematic view of the section of the large elastic sealing ring and the elastic sealing ring;

[0011] Figure 4 It is Figure 1 It is a schematic view of the three-dimensional structure of the driving nut;

[0012] Figure 5 It is Figure 1 It is a schematic view of the three-dimensional structure of the annular wedge and the spring ring.

[0013] The names of the components shown in the figure are as follows:

[0014] 1, hanger body, 2, driving nut, 3, annular wedge, 4, spring ring, 5, metal sealing ring, 6, support ring, 7, round nut, 8, set screw, 9, large elastic sealing ring, 10, elastic sealing ring, 11, tubing head or casing head cross. DETAILED DESCRIPTION

[0015] The specific embodiments of the present application are further described below with reference to the accompanying drawings:

[0016] Figure 1 、 Figure 2 In the present application, the hanger body 1 adopts the main body structure of the core shaft type hanger with elongated neck, which is a hollow cylindrical body part with different diameters. The locking mechanism composed of the driving nut 2, the annular wedge block 3 and the spring ring 4 is installed at the upper part of the hanger body 1. The metal sealing assembly with three layers of internal and external sealing wires is installed on the cylindrical body and the stud body at the lower part of the hanger body 1. The super-high pressure resistant large elastic sealing ring 9 is installed in the groove at the middle part of the hanger body 1. The super-high pressure resistant elastic sealing ring 10 is installed in the two grooves at the upper part of the hanger body 1. A through hole with tapered threaded holes at both ends and a cylindrical hole in the middle is processed in the center of the hanger body 1, which facilitates hoisting, connecting the oil pipe or casing and forming the middle passage.

[0017] The metal sealing assembly with three layers of internal and external sealing wires used in the present application is composed of the metal sealing ring 5 with the "eight" shaped cross section, the support ring 6 with the trapezoidal cross section, the round nut 7 and the set screw 8 from top to bottom. The outer diameters of the metal sealing ring 5, the support ring 6 and the round nut 7 decrease gradually, which are installed in the center stepped hole of the tubing head or casing head cross 11. The tubing or casing suspended below is relied on the weight to seat and extrude the support ring 6 and the three layers of metal sealing ring 5. The edges of the metal sealing ring 5 respectively contact with the cylindrical body of the hanger body 1 and the wall of the center stepped hole of the tubing head or casing head cross 11, forming the sealing with three layers of internal and external metal sealing wires.

[0018] Figure 1 、 Figure 2 、 Figure 3 In the present application, the super-high pressure resistant large elastic sealing ring 9 and the elastic sealing ring 10 used in the present application have parallel straight edges on the cross section, an arc-shaped groove on the inner edge and an arc-shaped protrusion on the outer edge. The main body material is "FKM fluororubber" or "HNBR high saturated hydrogenated nitrile rubber". A spring ring made of stainless steel wire is inlaid at each shoulder of the protrusion end, which can effectively reduce the deformation and damage under super-high pressure working condition.

[0019] Figure 1 、 Figure 2 、 Figure 4 、 Figure 5The locking mechanism of the present application is composed of a driving nut 2, an annular wedge 3 and a spring ring 4. The driving nut 2 is a smooth cylinder in periphery, with a threaded hole in the middle for connecting with the hanger body 1, 4-6 symmetrical axial grooves on the upper end for the rotation of the driving nut 2, and a large chamfer on the lower end for pushing the annular wedge 3 to extend and lock. The annular wedge 3 is an annular assembly with a diameter less than or equal to the maximum diameter of the hanger body 1, with a flat upper surface and a flat lower surface, and a chamfer less than or equal to 30° on the edge, and a groove cut in the middle of the outer circumference, with a central hole mostly processed into an opening upward and a large chamfer for wedge with the lower end of the driving nut 2. The annular wedge 3 is symmetrically cut into 4-6 pieces, and is bound together by the spring ring 4 in the groove in the middle of the outer circumference. In the central stepped hole of the tubing head or casing head cross 11, a groove is cut at a position relative to the annular wedge 3, which is greater than or equal to the thickness of the annular wedge 3, so as to cooperate with the annular wedge 3 to lock the hanger parts.

[0020] The present application is assembled Figure 1 After assembly, rotating the driving nut 2 upward moves the annular wedge 3 to shrink under the action of the spring ring 4 to the maximum diameter of the hanger body 1. The hanger body 1 is connected with the derrick and the tubing or casing put into the well through the tapered threaded holes on the upper and lower ends of the central hole of the hanger body 1. With the help of the derrick, the present application is put into the central stepped hole of the tubing head or casing head cross 11, and the large elastic sealing ring 9 and the metal sealing assembly on the hanger body 1 are sealed under the gravity of the tubing or casing. Then, rotating the driving nut 2 downward pushes the annular wedge 3 to wedge into the corresponding groove of the tubing head or casing head cross 11 to lock, and the annular wedge 3 is always locked when the driving nut 2 is not moved. Then, the derrick is removed, and the installation of other parts can be carried out. When the hanger needs to be disassembled, only the annular wedge 3 needs to be rotated upward to shrink to the maximum diameter of the hanger body 1.

Claims

1. A spindle-type hanger with a built-in locking mechanism for wellhead equipment, comprising a hanger body, a locking mechanism, and two types of sealing elements; characterized in that: The hanger body is a core shaft hanger with an elongated neck, which is a main structural part. A locking mechanism composed of a driving nut, a ring wedge and a spring ring is installed at the upper part of the hanger body. A metal sealing assembly with three layers of inner and outer sealing wires is installed on the cylindrical body and the stud body at the lower part of the hanger body. A super-high pressure resistant large elastic sealing ring is installed in the groove at the middle part of the hanger body. Two super-high pressure resistant elastic sealing rings are installed in the two grooves at the upper part of the hanger body. The metal sealing assembly with three layers of inner and outer sealing wires is composed of three layers of superimposed metal sealing rings with an "eight" shaped cross section, a support ring with a trapezoidal cross section, a round nut and a set screw from top to bottom. The super-high pressure resistant large elastic sealing ring and the elastic sealing ring have parallel straight edges on the cross section, an arc-shaped groove on the inner edge and an arc-shaped protrusion on the outer edge. The main material is "FKM fluorine rubber" or "HNBR high saturated hydrogenated butadiene-acrylonitrile rubber". A spring ring made of stainless steel wire is inlaid at each shoulder of the protrusion end. The ring wedge is a ring-shaped combined part with a diameter less than or equal to the maximum diameter of the hanger body. The upper and lower parts of the ring wedge are flat surfaces, and the edges are processed with chamfers less than or equal to 30°. A groove is cut in the middle of the outer circumference, and the center hole is mostly processed into an open upward large chamfer that engages with the lower end of the driving nut. The ring wedge is symmetrically cut into 4-6 pieces, which are bound together by the spring ring in the middle groove of the outer circumference.

2. The hanger for wellheads according to claim 1, characterized in that: The periphery of the driving nut is a smooth cylindrical body, and the middle is a threaded through hole. The upper end is processed with 4-6 symmetrical axial grooves, and the lower end is processed with a large chamfer.

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