A flange type tubing hanger for oil and gas production wellhead devices

Abstract

A flange type tubing hanger for oil and gas wellhead devices is a new integral component that combines a reducer and a mandrel type tubing hanger in the wellhead device. In the center hole that runs through the upper and lower ends, both ends are processed into tapered pipe threaded holes, and a cylindrical threaded hole is processed at intervals below the upper tapered pipe threaded hole. On the upper and lower end faces of the flange, a trapezoidal gasket ring groove and evenly distributed threaded blind holes and cylindrical through holes are processed respectively. On the circumference of the flange with the largest diameter, a grease injection valve and a pressure relief valve that are connected to the four-way center step hole of the tubing head are symmetrically installed; on the cylinder and stud body below it, an ultra-high pressure resistant elastic sealing ring and a set of metal sealing components with three layers of inner and outer sealing lines are respectively installed. Therefore, it has the dual functions of a reducer and a tubing hanger in the wellhead device, and avoids the problems of bulkiness, leakage, looseness and high price caused by fixing the tubing hanger with locking screws.

Description

Technical Field

[0001] The invention relates to wellhead device components in petroleum machinery and drilling equipment. Background Art

[0002] At present, the tubing hanger components in the existing oil or gas wellhead devices at home and abroad are all installed in the upper part of the central step hole of the tubing head four-way in the wellhead device, and are fixed by the locking screws with sealing components evenly distributed on the periphery of the upper flange of the tubing head four-way. Although the basic structure and fixing method of the existing tubing hanger have a long history of use, there are still many unsatisfactory problems: First, the numerous locking screws with sealing components evenly distributed on the periphery of the upper flange of the tubing head four-way weaken the structural strength of the tubing head four-way. In order to ensure its safety under ultra-high pressure conditions, the thickness of the upper flange has to be artificially increased, resulting in the huge and heavy product and waste of metal materials. Second, if one of the sealing components of more than ten evenly distributed locking screws leaks, it is urgent to repair it to prevent fire or poisoning accidents; the repair of high-pressure and ultra-high pressure oil or gas production equipment will inevitably consume manpower and material resources, and if a safety accident occurs, the loss will be greater. Third, it is not easy to process more than ten radial threaded high-precision step holes evenly distributed on the flange of the tubing head four-way, the same number of complex locking screws and matching high-pressure resistant sealing components, which requires a lot of manpower and material resources, increasing production costs and product prices. Fourth, the sealing of the connection between the upper end of the tubing hanger and the center hole of the reducer has always been a thorny problem; affected by various factors such as sealing space, repeated positioning, form and position tolerances and ultra-high pressure, oil and gas leakage is very likely to occur here, which will corrode and damage the metal sealing gasket ring between the tubing head four-way and the reducer, causing major oil and gas leakage accidents. Fifth, although the existing tubing hanger is tightened and fixed with a large number of locking screws, the tubing hanger still loosens and rotates in complex well conditions and subsequent operations, which will cause the sealing of the tubing hanger to fail or cause the tubing connected by the tapered pipe thread to fall off, thereby causing major equipment accidents and economic losses. Therefore, it is necessary to innovate the fixing method of the tubing hanger. Summary of the invention

[0003] The purpose of the present invention is to design a new flange type tubing hanger, which can replace the two different components of the original reducer and tubing hanger in the wellhead device, and avoid many problems existing in the existing tubing hanger fixed with locking screws.

[0004] The present invention comprises a flange hanging body, two sealing members and parts for grease injection; the characteristics of the present invention are as follows: the upper part of the flange hanging body is a flange with a large diameter and a step, and the lower part is a columnar body with a small diameter and different thicknesses; in the central hole penetrating the upper flange and the lower columnar body, both the upper and lower ends are processed into tapered pipe threaded holes, and a cylindrical threaded hole is processed at intervals below the upper tapered pipe threaded hole; the upper end face of the flange is processed with a trapezoidal gasket ring groove and evenly distributed threaded blind holes; the lower end face of the flange is processed with a trapezoidal gasket ring groove and evenly distributed cylindrical through holes; on the circumference of the largest diameter of the flange, two stepped holes with tapered pipe threads at the inlet and right-angle turns at the end are symmetrically processed, and a grease injection valve and a pressure relief valve are respectively installed at the orifices; in the groove in the middle of the cylinder with the thickest diameter below the flange hanging body, an elastic sealing ring resistant to ultra-high pressure is installed; on the cylinder and the stud body below the thickest cylinder of the flange hanging body, a metal sealing component with three layers of inner and outer sealing lines is installed.

[0005] Furthermore, the metal sealing assembly of the three-layer inner and outer sealing lines is composed from top to bottom of three stacked metal sealing rings with "eight"-shaped cross-sections, a support ring with a trapezoidal cross-section on the top, a round nut and a set screw.

[0006] Furthermore, the ultra-high pressure resistant elastic sealing ring has parallel straight edges on the upper and lower sides of its cross section, an arc-shaped groove on the inner side, and an arc-shaped protrusion on the outer side; its main material is "FKM fluororubber" or "HNBR highly saturated hydrogenated nitrile rubber", and a spring ring made of stainless steel wire is inlaid on each shoulder of its protruding end.

[0007] Since the present invention adopts a brand-new flange type oil pipe hanger, which replaces the two different components of the original reducer and the oil pipe hanger in the wellhead device, when the flange of the flange type oil pipe hanger is fixed on the oil pipe head four-way by stud nuts and sealing gaskets, the oil pipe hanger is firmly fixed in the center hole of the oil pipe head four-way, thereby eliminating the need for a large number of locking screws and their matching sealing components uniformly distributed on the periphery of the upper flange in the oil pipe head four-way for compressing and fixing the oil pipe hanger, thereby avoiding the increase in the thickness of the upper flange due to weakening the structural strength of the oil pipe head four-way, avoiding the accident of oil and gas leakage at the sealing point of the large number of locking screws, avoiding the problem of difficult and easy leakage of the sealing at the connection between the upper end of the oil pipe hanger and the reducer, avoiding the problem of failure of the seal due to loosening or rotation of the oil pipe hanger, or causing the accident and economic loss of the oil pipe connected with the tapered pipe thread to fall off. In addition, the present invention adopts an elastic sealing ring made of a new structural composite material to replace the commonly used O-type rubber sealing ring, which can significantly improve its ultra-high pressure resistance performance; and adopts a metal sealing assembly with three layers of inner and outer sealing lines to replace the commonly used metal sealing assembly with one or two sealing lines, so that the reliability of the metal seal is further improved, thereby further improving the overall quality and performance of the wellhead device. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic cross-sectional view of the overall structure of the present invention;

[0009] Figure 2 for Figure 1 , a schematic diagram of an enlarged cross section of the elastic sealing ring;

[0010] Figure 3 The present invention is a schematic cross-sectional view of the structure installed on a tubing head spool in a wellhead device.

[0011] The names of the parts indicated by the numbers in the figure are as follows:

[0012] 1. Flange suspension body, 2. Grease injection valve, 3. Elastic sealing ring, 4. Metal sealing ring, 5. Support ring, 6. Round nut, 7. Set screw, 8. Pressure relief valve, 9. Stud nut, 10. Sealing gasket, 11. Oil pipe head cross. DETAILED DESCRIPTION

[0013] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0014] Figure 1 , Figure 2 The present invention is composed of a flange suspension body with a unique structure, two new sealing components and grease injection parts. The flange suspension body 1 has a large diameter flange with a step on the top and a small diameter columnar body with different thicknesses on the bottom. In the center hole that passes through the upper flange and the lower columnar body, both the upper and lower ends are processed into tapered pipe threaded holes, which are used to connect the hanger rod and the oil pipe respectively. Below the tapered pipe threaded hole at the upper end, a cylindrical threaded hole is processed at intervals for installing a back pressure valve when the wellhead device is repaired. On the upper end face of the flange, there is a trapezoidal gasket groove and evenly distributed threaded blind holes for connecting to the oil or gas production tree. On the lower end face of the flange, there is a trapezoidal gasket for connecting to the tubing head cross 11. Grooves and evenly distributed cylindrical through holes; on the circumference of the largest diameter of the flange, two stepped holes with tapered pipe threads at the inlet and right-angle turns at the end are symmetrically processed, and a grease injection valve 2 and a pressure relief valve 8 are respectively installed at the orifices to inject sealing grease into the gap between the flange hanger 1 and the tubing head cross 11; in the groove in the middle of the thickest diameter cylinder below the flange hanger 1, an ultra-high pressure resistant elastic sealing ring 3 is installed; on the cylinder and stud body below the thickest cylinder of the flange hanger 1, a metal sealing component with three layers of inner and outer sealing lines is installed for sealing the tubing hanger.

[0015] The metal sealing assembly of the three-layer inner and outer sealing line used in the present invention is composed of three layers of superimposed metal sealing rings 4 with an "eight"-shaped cross section, a support ring 5 with a trapezoidal cross section on the top, a round nut 6 and a set screw 7. The outer diameters of the metal sealing ring 4, the support ring 5 and the round nut 6 decrease step by step, and are installed in the central step hole of the casing spool 11. Relying on the weight of the oil pipe suspended below, the support ring 5 and the three-layer metal sealing ring 4 are seated and squeezed, so that the edge of the metal sealing ring 4 contacts the cylindrical body of the flange suspension body 1 and the central step hole wall of the oil pipe head spool 11, respectively, to form a metal seal with three layers of inner and outer sealing lines.

[0016] Figure 3 The ultra-high pressure resistant elastic sealing ring 3 used in the present invention has parallel straight edges on the upper and lower sides of the cross section, an arc-shaped groove on the inner side, and an arc-shaped protrusion on the outer side; its main material is "FKM fluororubber" or "HNBR highly saturated hydrogenated nitrile rubber", and a spring ring made of stainless steel wire is inlaid on the two shoulders of its protruding end, which can effectively reduce its deformation and breakage under ultra-high pressure conditions.

[0017] When in use, the present invention connects the suspension rod and the oil pipe respectively through the tapered pipe threaded holes at the upper and lower ends of the center hole of the flange suspension body 1, and then the columnar body below the flange suspension body 1 together with the elastic sealing ring 3 and the metal sealing component 4 are sealed with the stepped hole in the center of the oil pipe head four-way 11, and then the present invention is fixed above the oil pipe head four-way 11 with the stud nut 9 and the sealing gasket 10; and the sealing grease is injected into the cavity in the central step hole of the oil pipe head four-way 11 through the grease injection valve 2 and the pressure relief valve 8 installed on the upper flange edge; then the suspension rod is folded off, and connected with the oil tree or gas tree through a trapezoidal gasket groove on the upper end face of the flange and the evenly distributed threaded blind holes, so that oil or gas production can be carried out.

Claims

1. A flange type tubing hanger for oil and gas production wellhead devices, comprising a flange hanger, two sealing members and grease injection parts; its characteristics are: The upper part of the flange suspension body is a flange with a large diameter and a layer of steps, and the lower part is a columnar body with a small diameter and different thicknesses; in the central hole that passes through the upper flange and the lower columnar body, both the upper and lower ends are processed into tapered pipe threaded holes, and a cylindrical threaded hole is processed at intervals below the upper tapered pipe threaded hole; on the upper end face of the flange, a trapezoidal gasket groove and evenly distributed threaded blind holes are processed; on the lower end face of the flange, a trapezoidal gasket groove and evenly distributed cylindrical through holes are processed; on the circumference of the largest diameter of the flange, two stepped holes with tapered pipe threads at the inlet and right-angle turns at the end are symmetrically processed, and a grease injection valve and a pressure relief valve are installed at the orifices respectively; in the groove in the middle of the cylinder with the thickest diameter below the flange suspension body, an elastic sealing ring resistant to ultra-high pressure is installed; on the cylinder and stud body below the thickest cylinder of the flange suspension body, a metal sealing assembly with three layers of internal and external sealing lines is installed; The metal sealing assembly of the three-layer inner and outer sealing lines is composed of three layers of superimposed metal sealing rings with "eight"-shaped cross-sections, a support ring with a trapezoidal cross-section on the top, a round nut and a set screw from top to bottom; The ultra-high pressure resistant elastic sealing ring has parallel straight edges on the upper and lower sides of the cross section, an arc-shaped groove on the inner side and an arc-shaped protrusion on the outer side; its main material is "FKM fluororubber" or "HNBR highly saturated hydrogenated nitrile rubber", and a spring ring made of stainless steel wire is inlaid on each shoulder of its protruding end.

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