RU2707619C1 - Metal-to-metal-type seal in column head for underwater wells - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to sealing of annular gaps between conductor and installed in it suspension of technical pipe string during operation of underwater wells. Disclosed is a seal, made with three-step annular seals of metal-metal type and having housing 5, pusher 17 with shear transport element 18, two fixing rings 23, 29 and lock 35. Housing 5 comprises outer sealing elements 6 including lower 7, middle 8 and upper 9 sealing bands, conjugated with conductor 1, forming the first labyrinth system. Housing 5 comprises inner sealing elements 10 including bottom 11, middle 12 and top 13 sealing bands coupled with suspension 2 to form second labyrinth system. Said belts 11, 12, 13 can contact with support surface 3 of suspension 2 made at angle 4 equal to not more than 10° relative to well axis. Surfaces formed by tops of belts 11, 12, 13, and surfaces formed by tops of belts 7, 8, 9 have angles of the same range "X" with the well axis. Also, housing 5 comprises contact surfaces 14, 15, which are located one relative to the other at angle of 16. Pusher 17 comprises contact surfaces 19, 20, one of which has groove 21 for water discharge. Surfaces 19, 20 are located one relative to the other at angle 22 equal to angle 16 of surfaces 14, 15 or less. Pusher 17 has the possibility of fixing conductor 1 relative to suspension 2 from axial displacement relative to each other by means of rings 23, 29. Ring 23 can interact with suspension 2, and ring 29 can interact with conductor 1. Each of rings 23, 29 has small-tooth toothed profiles, and grooves – small-module teeth. Width 28, 34 of rings 23, 29 is smaller than width 27, 33 of grooves 25, 31. And profiles can be fixed on teeth, and rings 23, 29 have possibility of interaction with lock 35.

EFFECT: higher sealing reliability of conductor and string suspension.

1 cl, 6 dwg

Description

The invention relates to a sealant used to seal annular gaps between the conductor and the suspension of the technical pipe string installed in it during the operation of subsea wells and made with three-stage metal-metal ring seals.

Known column head containing a cylindrical body, a cover, nozzles, a wedge-shaped suspension in the form of a cut sleeve, elastic lower and upper cuffs and an annular metal seal, RU No. 2146000 C1, ЕВВ 33/04, 02.27.2000.

Known devices for sealing the annular space of subsea wells, including combined seals, US 2013/0000920 A1 ЕВВ 33/035, ЕВВ 33/00, Е21В 33/128, 01/03/2013.

A known sealing system of an underwater drilling rig, US 7073591 B2, E21B 33/043, 07/11/2006; US 6520263 B2, E21B 33/035, 02/18/2003.

Known suspension of tubing of wellhead valves with metal-to-metal seals installed in the housing of the pipe head, consisting of a housing, seals, having annulus seals in the form of support, retaining rings and metal cuffs with conical inner and cylindrical outer surfaces, RU No. 2171358 C2, E21B 33/04, 07/27/2001.

A device is known for sealing the annulus of the mouth of an oil and gas producing well between a conductor and a production string, RU No. 2290393 C1, EV 33/04, 03/27/2005.

Known combined sealant containing a housing, a pusher (force transmission device), metal and polymer seals, support ring, US 2013/0000920 A1 EV 33/035, EV 33/00, EV 33/128, 03/03/2013.

In the known devices, features identical to the claimed invention were not found.

The closest analogue to the claimed invention is not found.

The present invention is based on the solution of the problem, which allows to increase the reliability of sealing of the conductor and suspension of the technical pipe string, to provide a reliable and enhanced mode of operation of the seal in subsea wells and to simplify technological operations.

The technical result of the present invention is the reliability of sealing the annular gaps between the conductor and the suspension of the technical pipe string by performing a gasket with three-stage metal-metal ring seals, design features of the geometry of the conical surfaces and their placement to each other, bearing external and internal sealing belts, in the execution of the pusher, which provides reliable fixation of the seal on the conductor and suspension of the technical pipe string due to the shape and size fixing rings and grooves under them, and to simplify installation work when installing the seal due to shear element.

According to the invention, a metal-metal seal in a subsea casing head provides sealing of annular gaps between the conductor and the suspension of the technical pipe string installed therein.

The sealant is made with three-stage O-rings of the metal-metal type.

The sealant has a housing, a pusher with a shear transport element, with locking rings, not less than two, with a lock made to move down.

In this case, the housing contains external sealing elements, including the lower, middle and upper sealing belts, conjugated with the conductor, together forming the first labyrinth system, and internal sealing elements, including the lower, middle and upper sealing belts, conjugated with the suspension of the technical pipe string, together forming the second labyrinth system.

Moreover, the sealing belts of the internal sealing elements have the possibility of contact with the supporting surface of the suspension of the technical pipe string, made at an angle equal to not more than 10 degrees relative to the axis of the well.

The surfaces formed by the vertices of the sealing belts of the inner sealing elements and the surfaces formed by the vertices of the sealing belts of the outer sealing elements have angles of the same range with the axis of the well.

The housing also contains contact surfaces that are located relative to each other at an angle.

The pusher contains contact surfaces, one of which is made with a groove for discharging water, located one relative to the other at an angle equal to or less than the angle of contact surfaces of the housing.

These contact surfaces have a large active area when exposed to liquid pressure.

These contact surfaces have the ability to fix the conductor relative to the suspension of the technical pipe string from axial displacement relative to each other, by means of fixing rings.

One of the locking rings has the ability to interact with the suspension of the technical pipe string, and the other has the ability to interact with the conductor.

In addition, each of the retaining rings has fine modular gear profiles, and the grooves on the suspension of the technical pipe string and conductor, respectively, fine modular teeth.

Moreover, the width of the retaining rings is less than the width of the grooves with small module teeth and the small module gear profiles can be fixed on the small module teeth, and the locking rings have the ability to interact with the lock.

The applicant has not identified sources containing information about technical solutions identical to the present invention, which allows us to conclude that it meets the criterion of "novelty."

Due to the implementation of the distinguishing features of the invention (in conjunction with the features indicated in the restrictive part of the formula), important new properties of the object are achieved.

The implementation of the sealant with three-stage ring seals of the metal-metal type, the presence of external and internal sealing elements bearing the external and internal sealing belts, respectively, as well as structural features of the geometry of the conical surfaces of the external and internal sealing elements and their placement relative to each other can improve the reliability of sealing conductor and suspension of the technical pipe string and provide enhanced mode of operation of the seal in subsea wells x.

The implementation of the pusher, the fixing rings (their shape, size and grooves under them) provides reliable fixation of the seal on the conductor and suspension of the technical pipe string, ensuring reliable operation of the seal in subsea wells.

The execution of the shear transport element on the pusher simplifies the technological operations of the installation work when installing the seal.

The applicant is not aware of any publications that would contain information on the influence of the distinguishing features of the invention on the achieved technical result. In this regard, according to the applicant, it can be concluded that the claimed technical solution meets the criterion of "inventive step".

The invention is illustrated by drawings, which depict:

in FIG. 1 - Seal type metal-metal in the casing head for subsea wells, the process of lowering the seal, section;

in FIG. 2 - Metal-to-metal sealant in a casing head for subsea wells, Node A in FIG. one;

in FIG. 3 - Metal-to-metal sealant in a casing head for subsea wells, Node B in FIG. one;

in FIG. 4 - Sealant type metal-metal in the casing head for subsea wells, the installation process of the sealant, section;

in FIG. 5 - Sealant type metal-metal in the casing head for subsea wells, the compaction process, section;

in FIG. 6 - Seal type metal-metal in the casing head for subsea wells, the process of fixing the seal, section.

In FIG. 1-6 depicted:

Conductor - 1.

Suspension of the technical pipe string - 2,

supporting surface (suspension 2) - 3,

the angle of inclination (surface 3 relative to the axis of the well) - 4.

Case - 5.

External sealing elements (housing 5, coupled with the conductor 1) - 6,

lower sealing girdle (elements 6) - 7,

the middle sealing girdle (elements 6) - 8,

upper sealing girdle (elements 6) - 9.

Internal sealing elements (housing 5, coupled with the suspension 2) - 10,

lower sealing girdle (elements 10) - 11,

the middle sealing belt (elements 10) - 12,

the upper sealing girdle (elements 10) - 13.

Contact surface (housing 5) - 14.

Contact surface (housing 5) - 15.

The angle (between surfaces 14 and 15) is 16.

Pusher - 17,

shear transport element (on the pusher 17) - 18.

Contact surface (pusher 17) - 19.

Contact surface (pusher 17) - 20,

groove for water drainage (on surface 20) - 21.

The angle (between surfaces 19 and 20) is 22.

The fixing ring (with the possibility of interaction with the suspension of the technical pipe string 2) - 23,

finely modular gear profiles (rings 23) - 24,

groove (rings 23) - 25,

fine-grained teeth (grooves 25) - 26.

Width (grooves 25) - 27,

width (rings 23) - 28.

The fixing ring (with the possibility of interaction with the conductor 1) - 29,

finely modular gear profiles (rings 29) - 30,

groove (rings 29) - 31,

fine-grained teeth (grooves 31) - 32.

Width (grooves 31) - 33,

width (rings 29) - 34.

The lock (with the possibility of interaction with the locking rings 23, 29) - 35.

A metal-metal sealant in a casing head for subsea wells provides sealing of annular gaps between the conductor 1 and the suspension of the technical pipe string 2 installed in it.

The sealant is made with three-stage O-rings of the metal-metal type and has a housing 5, a pusher 17 with a shear transport element 18, at least two locking rings 23 29, a lock 35 with the ability to move down.

In this case, the housing 5 contains external sealing elements 6, including the lower 7, middle 8 and upper 9 sealing belts.

The lower 7, middle 8 and upper 9 sealing belts are paired with the conductor 1, together forming the first labyrinth system.

In this case, the housing 5 contains internal sealing elements 10, including the lower 11, middle 12 and upper 13 sealing belts.

The lower 11, middle 12 and upper 13 sealing belts are interfaced with the suspension of the technical pipe string 2, together forming a second labyrinth system.

Moreover, the sealing belts 11, 12, 13 of the internal sealing elements 10 have the ability to contact with the supporting surface 3 of the suspension of the technical pipe string 2, made at an angle 4 equal to not more than 10 degrees relative to the axis of the well.

The surfaces formed by the vertices of the sealing belts 11, 12, 13 of the inner sealing elements 10 and the surfaces formed by the vertices 7, 8, 9 of the outer sealing elements 6 have angles of the same range “X” with the axis of the well.

The housing 5 also contains contact surfaces 14, 15, which are located relative to each other at an angle 16 and have a large active area when exposed to liquid pressure

The pusher 17 contains contact surfaces 19, 20, one of which is made with a groove 21 for discharging water.

The contact surfaces 19, 20 are located one relative to the other at an angle 22 equal to the angle 16 of the location of the contact surfaces 14, 15 of the housing 5 or less.

The pusher 17 has the ability to fix the conductor 1 relative to the suspension of the technical pipe string 2 from axial displacement relative to each other, by means of locking rings 23, 29.

One of the locking rings 23 has the ability to interact with the suspension of the technical pipe string 2, and the other locking ring 29 has the ability to interact with the conductor 1.

Moreover, each of the retaining rings 23, 29 has fine-grained gear profiles 24, 30, and grooves 25, 31 on the suspension of the technical pipe string 2 and on the conductor 1, respectively, fine-grained teeth 26, 32.

Moreover, the width 28, 34 of the locking rings 23, 29 is less than the width 27, 33 of the grooves 25, 31 with fine-grained teeth 26, 32.

And the fine-grained gear profiles 24, 30 have the ability to fix on the fine-grained teeth 26, 32, and the locking rings 23, 29 have the ability to interact with the lock 35.

Work with a sealant

The sealant is lowered into the well on the tool for its installation.

As soon as the lower sealing girdle 11 of the internal sealing elements 10 touches the supporting surface 3 on the suspension of the technical pipe string 2 (Fig. 1), a force appears perpendicular to the axis of the well stretching it.

In this case, the lower girdle 7 of the outer sealing elements 6 will begin to approach the surface of the conductor 1 and, with a certain axial force, the transport shear element 18 will be cut off on the pusher 17.

The pusher 17 with its contact surface 20 (Fig. 4) will begin to act on the contact surface 15 of the housing 5, betraying the axial load, and, at the same time, creating a force perpendicular to the axis of the well, which will begin to unfold the contact surface 15 and press the upper sealing band 9 of the outer sealing elements 6 to the surface of the conductor 1.

At the same time around the pusher 17, its contact surface 19, the contact surface 14 of the housing 5 will begin to unfold and the upper sealing girdle 13 will approach the supporting surface 3 of the suspension of the technical pipe string 2.

After the contact of the sealing belts 11, 12, 13 with the supporting surface 3, and the upper sealing belt 9 with the conductor 1 (Fig. 5), the points of application of force from the axial movement of the pusher 17 will be between the lower 11 and the upper 13 sealing belts (in the middle zone 12 of the sealing belt) and between the lower 7 and upper 9 sealing belts (in the area of the middle sealing belt 8), creating the final stress for sealing.

The groove 21 in the process of moving the pusher 17 will let water out from under it, which is necessary to continue the movement of the pusher 17 to the bottom, and when the liquid pressure rises above the seal, during the operation of the seal, it will pass to the contact surfaces 15 and 19, with a large active area , the housing 5 and the pusher 17, respectively, which will create additional clamping force of all the sealing belts.

Upon reaching a certain axial load from the tool on the seal, the lock 35 is activated, which when moving down acts on the locking rings 23 and 29.

The locking rings 23 and 29 will go into the grooves 25 and 31, which are made wider than the locking rings 23 and 29 and have the ability to be fixed on the fine teeth 26 and 32 of the grooves 25 and 31 with the fine modular gear profiles 24 and 30 (Fig. 6). In this case, the tolerances for the manufacture of axial and radial dimensions of the seal and the two pipes to be sealed are compensated, as well as their axial fixation relative to each other.

When lifting the tool at the wellhead, the seal is automatically disconnected.

Operation with the seal is illustrated in FIG. 1, FIG. 4, FIG. 5, FIG. 6:

FIG. 1 - the first touch of the lower 11 sealing girdle with the supporting surface 3 of the suspension of the technical pipe string 2 in the process of lowering the seal.

FIG. 4 - slice shear transport element 18 and the touch of the pusher 17, its surface 20, surface 15 on the housing 5.

FIG. 5 - touching the lower 11, middle 12, upper 13 sealing belts of the supporting surface 3 of the suspension of the technical pipe string 2 and touching the lower 7 sealing band of the surface of the conductor 1.

FIG. 6 - touching all sealing belts 7, 8, 9, 11, 12, 13 of the sealing surfaces, the interference fit and fixing the retaining rings 23 and 29 in the grooves 25 and 31.

In the event of an emergency, the fluid pressure above the seal will increase in the column head. The fluid will try to pass over the seal down to the bottom. It will be held by the upper sealing belts of the two labyrinth systems. In this case, the liquid through the groove for water drainage on the contact surface of the pusher will enter the contact surfaces of the housing, which have a large active area when exposed to liquid pressure.

These contact surfaces will tend to press against the pipe walls by pressure, and at the same time, even stronger, pressing the upper and middle sealing bands of the outer and inner sealing elements against the pipe walls, respectively, of the suspension and the conductor.

An expansion chamber is formed between each pair of sealing belts. Two chambers in each system create a pressure drop that unloads each subsequent belt. Thus, a gradual decrease in pressure and reliable sealing are carried out.

The proposed "Metal-metal type sealant in a casing head for subsea wells" can be manufactured industrially, which is confirmed by the design and technological studies of the main strength characteristics in structural units, and testing of prototypes, studying and substantiating operational modes of the proposed technical solution determines according to the applicant, compliance with his criterion of "industrial applicability".

The proposed technical solution improves the sealing reliability of the conductor and suspension of the technical pipe string, provides a reliable and enhanced operating mode of the seal in subsea wells and simplifies technological operations.

Claims (1)

A metal-metal type sealant in a casing head for underwater wells providing sealing of annular gaps between the conductor and the suspension of the technical pipe string installed in it, characterized in that the sealant is made with three-stage metal-metal ring seals and has a housing, a pusher with a shear transport element , with locking rings, not less than two, with a lock made with the possibility of moving downward, while the housing contains external sealing elements, including the lower one, with the middle and upper sealing bands associated with the conductor, together forming the first labyrinth system, and the internal sealing elements, including the lower, middle and upper sealing bands, conjugated with the suspension of the technical pipe string, together forming the second labyrinth system, and the sealing belts of the internal sealing elements have the possibility of contact with the supporting surface of the suspension of the technical pipe string, made at an angle equal to not more than 10 ° relative to the axis of the well, and the surface formed the vertices of the sealing belts of the internal sealing elements, and the surfaces formed by the vertices of the sealing belts of the external sealing elements, have the same range of angles with the axis of the well, also the housing contains contact surfaces that are located one relative to the other at an angle, and the pusher contains contact surfaces, one of which made with a groove for discharging water, located one relative to another at an angle equal to or less than the angle of contact surfaces of the housing, having a large active area when exposed to liquid pressure and having the ability to fix the conductor relative to the suspension of the technical pipe string from axial displacement relative to each other by means of locking rings, one of which has the ability to interact with the suspension of the technical pipe string, and the other has the ability to interact with the conductor, each of the retaining rings has fine modular gear profiles, and the grooves on the suspension of the technical pipe string and on the conductor, respectively, are shallow modular teeth, and the width of the retaining rings is less than the width of the grooves with small-modular teeth and the small-modular gear profiles can be fixed on small-modular teeth, and the locking rings have the ability to interact with the lock.

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