RU2712865C1 - Non-metallic sealing element - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to device used in operation of offshore and ground wells and can be used for sealing annular ring space. Disclosed is a non-metallic sealing element for sealing an annular space between a casing hanger body and a column body of a column of a conductor, comprising a lower stop with an inner annular groove, on lower section of which there are slots made with possibility of arrangement of limiting segments, housing containing first, second and third sections, upper stop containing end element, first and second intermediate thrust elements, first and second non-metallic seals. At that, the first section of the body comprises an internal recess forming the space for placement of the end element of the upper stop, and is a collet comprising the first row of segments made with possibility of gear coupling with the first intermediate thrust element, and a second row of segments configured to gear coupling with second intermediate thrust member. Second section of the body is made with thickness substantially equal to the width of the inner annular groove of the lower thrust, wherein between the second portion of the body and the column body of the column of the conductor there is a first non-metallic seal, and between second section of housing and housing of casing string suspension there is a second non-metallic seal. Third section of housing comprises external groove made with possibility of fixing spring ring in initial position, and a longitudinal recess made with possibility of fixing the body relative to the lower stop by placing in the recess part of the limiting segments protruding from the grooves of the lower stop with provision of abutment.

EFFECT: reduced value of compression force for activation of sealing element and increased reliability of sealing of casing pipes.

1 cl, 10 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a device used in the operation of offshore and onshore wells, and in particular to the design of a non-metallic sealing element designed to seal the annular space between the casing suspension housing and the conductor casing head housing.

BACKGROUND

Various types of seals are used to seal the annular space between the casing suspension housing and the casing of the casing string head, designed to prevent or reduce leakage of liquid or gas through the gaps between the parts.

Typically, metal-to-metal seals are used for these purposes. Also, in case of damage to the sealing surfaces, an emergency annular seal with a non-metallic seal is usually used.

A particular version of a non-metallic seal is a seal that requires compression to activate.

Moreover, in the context of this document, by activating the seal, one should understand the process of transition of the seal from its initial position to the working position, in which by compressing the elastic seal, sealing of the annular space between the casing suspension housing and the conductor casing column head housing is achieved.

Similarly, deactivation of a seal should be understood as the process of transition of a seal from its working position to its original position.

When using a non-metallic seal that requires compression to activate, it is necessary to fix the compression mechanism to ensure that the deformation of the non-metallic seal is guaranteed to maintain its tightness.

The closest technical solution, selected as a prototype of the claimed invention is a combined casing seal for subsea wells, known from document RU 2691416 C1 (published on 06/13/2019).

A seal known from the aforementioned document includes a sealing assembly, an annular sleeve, an anchor, and a shank. The sealing unit consists of an annular support with a groove, elastic seals and metal seals placed in a composite housing. The composite case is made of two parts equipped with an axis. The axis through the support groove has the ability to limit the movement of the support in the housing. The seals are made of rubber and contain a rubber seal in the shape of a trapezoid in a longitudinal section with a concave large base, with rounded peaks, and a mirror-shaped rubber seal. Between the seals there is a rubber seal in the form of a polygon in a longitudinal section with rounded peaks, which is separated from the seals by metal plates, respectively. The plates follow the shape of the seals and are used as dividers in the transport position and as seals in the operating position of the seal. The assembly contains a shear pin with the possibility of interaction of the support with part of the housing. Part of the housing is connected by a shear pin to the sleeve with grooves at the end, in which the wedge dies of the anchor are placed. The sleeve is anchored and spring loaded with it. At the anchor is a part of the housing connected with it through the circlip. At the anchor are crackers for fixing the seal in the groove on the conductor and crackers for fixing the seal in the groove on the technical column. The shank is made with a retaining ring, connected to the seal fitting tool and has the ability to fix the seal on the conductor and on the technical column at the same time.

The technical solution, known from the document RU 2691416 C1, allows for the autonomous use of a combined seal in conditions of high axial pressure when lowering into a subsea well.

Nevertheless, during operation of the casing pipes in the well, additional axial loads act on the nodes of their joints, which arise, in particular, due to the effect of thermal expansion of the casing pipes in the well.

When these axial loads occur, the compression force, ensuring the tightness of the known seal, is weakened due to the fact that these loads are perceived by the dies of the known device.

In addition, in order to deactivate the known seal, it is necessary to exert considerable force, which will make it possible to disrupt the dies of the known seal, thereby ensuring the said deactivation.

Thus, the technical problem solved by the creation of the present invention was the need to create a non-metallic sealing element that provides reliable sealing of the annular space between the casing suspension housing and the casing of the conductor column head under conditions of increased axial loads during operation, including those caused by thermal casing extension in the well.

In addition, the technical problem solved by the creation of the present invention was the need to create a non-metallic sealing element, which simplifies the deactivation process by reducing the amount of force that must be applied for the said deactivation.

SUMMARY OF THE INVENTION

The technical result achieved by the claimed invention is to reduce the amount of compression force necessary to activate the non-metallic sealing element and its fixation, achieved by limiting the linear movement of the elements compressing the non-metallic sealing element. Moreover, the magnitude of the compression force mentioned does not depend on the installation parameters, in particular, on the adhesion of the annular seal housing to the casing suspension housing, the presence of slurry on the supporting end, and the displacement of the bodies relative to each other. The compression ratio of the non-metallic sealing element itself does not depend on the axial loads acting on the structural elements of the non-metallic sealing element from the side of the casing string suspension and the casing column head housing, including those resulting from thermal expansion of the casing pipes.

Thus, by means of the claimed non-metallic sealing element, an increase in the reliability of casing sealing during operation is achieved.

In addition, the non-metallic sealing element according to the present invention simplifies the process of deactivating the non-metallic sealing element by reducing the amount of force that must be applied for said deactivation.

Moreover, the magnitude of the deactivation force of the claimed non-metallic sealing element is several times less than the activation force. The said deactivation force does not depend on the activation force and can be arbitrarily adjusted using shear elements of the claimed non-metallic sealing element.

The stated technical problem and the claimed technical result are respectively solved and achieved due to the fact that the non-metallic sealing element proposed according to the present invention for sealing the annular space between the casing suspension housing and the conductor casing of the column head contains:

a lower stop with an inner annular groove located in a cavity formed by an annular protrusion made along the perimeter of the outer surface of the casing suspension housing between the casing suspension housing and the casing of the column head of the conductor, while the portion of the lower stop adjacent to the casing of the column head of the conductor, contains grooves made with the possibility of placing bounding segments;

a housing containing the first, second and third sections;

an upper stop comprising an end member;

first and second intermediate thrust elements;

first and second non-metallic seals;

moreover, the first section of the housing contains an inner recess, forming a space for accommodating the end element of the upper stop, and is a collet containing the first row of segments made with the possibility of gearing with the first intermediate stop element, and the second row of segments made with the possibility of gearing with the second intermediate thrust element;

the second section of the casing is made substantially equal to the width of the inner annular groove of the lower stop, while the first non-metallic seal is placed between the second section of the casing and the casing of the column head of the conductor, and the second non-metal seal is placed between the second section of the casing and the casing of the casing;

the third section of the housing contains an external groove made with the possibility of fixing the spring ring in the initial position, and a longitudinal recess made with the possibility of fixing the housing relative to the lower stop by placing in the said recess part of the limiting segments protruding from the grooves of the lower stop to ensure fit;

the first and second intermediate stop elements are made with the possibility of fixing relative to each other, as well as the housing by means of fixing pins;

moreover, the housing, the intermediate stop elements and the upper stop are arranged to linearly move from the initial position to the working position, ensuring the movement of the spring ring from the groove into the longitudinal recess of the third section of the housing and activation of non-metallic seals;

the upper stop is made with the possibility of linear movement when the shear elements are destroyed by an amount limited by the guide pins from the position in which the end element of the upper stop is located in the inner recess of the first section of the housing to the position in which the end element of the upper stop is removed from the inner recess the first section of the housing, thus providing a displacement of the first and second row of segments of the collet of the first section of the housing towards each other and the movement of the intermediate thrust el items to ensure the deactivation of non-metallic seals.

Additionally, the posed technical problem and the claimed technical result are respectively solved and achieved due to the fact that non-metallic seals can be made of rubber, elastomer or other elastic material.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, as well as its other aspects and characteristics, the description is given with reference to the accompanying drawings, where:

in FIG. 1 shows a non-metallic sealing element in its initial position;

in FIG. 2 shows a non-metallic sealing element in an activation position;

in FIG. 3-5 shows the deactivation of a non-metallic sealing element;

in FIG. 6-8 shows a General view of the housing of a non-metallic sealing element;

in FIG. 9 is a schematic cross-sectional view of the lower stop of a non-metallic sealing element;

in FIG. 10 schematically shows intermediate stop elements of a non-metallic sealing element in accordance with a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a non-metallic sealing element, designed to seal the annular space between the casing 1 of the column head of the conductor and the casing 2 of the suspension of the casing, and contains:

bottom stop 3,

building 4,

first and second non-metallic seals 5,

the first and second intermediate thrust elements 6,

top stop 7,

snap ring 8

bordering segments 9,

locking pins 10,

shear elements 11,

guide pins 12.

In the present invention, the lower stop 3 is placed between the casing suspension housing 2 and the conductor casing string head housing 1 in a cavity formed by an annular protrusion made along the perimeter of the outer surface of the casing suspension housing 2.

The lower stop 3 is an annular element, inside of which an annular groove is made around the entire perimeter, forming a part of the lower stop 3 adjacent to the casing 1 of the column head of the conductor, and a part of the lower stop 3 adjacent to the casing 2 of the casing.

In the grooves made around the perimeter of the lower stop part 3 adjacent to the housing 1 of the column head of the conductor column, the limiting segments 9 are placed so as to form a part of the limiting segments 9 protruding from the said grooves.

In the inner annular groove of the lower stop 3, a housing 4 is partially placed, which is an annular element and contains a first section, a second section and a third section.

In the first section of the housing 4, an internal undercut is made, while the first section of the housing 4 is a collet containing the first row of segments and the second row of segments having gear profiles for engaging the corresponding tooth profiles of the intermediate stop elements 6.

The second section of the housing 4 is made of a thickness substantially equal to the width of the inner annular groove made inside the lower stop 3.

Between the second section of the housing 4 and the shell 1 of the column head of the conductor string, as well as between the second portion of the shell 4 and the casing suspension housing 2, the first and second non-metallic seals 5 are placed.

The material from which the first and second non-metallic seals 5 can be made may be rubber, elastomer or other elastic material.

The third section of the housing 4 contains an external groove in which the spring ring 8 is placed in the initial position of the non-metallic sealing element.

Additionally, in the third section of the casing 4, a longitudinal recess is made, to which the bounding segments 9 abut with a part protruding from the grooves made around the perimeter of the lower stop part 3 adjacent to the casing 1 of the column head of the conductor column, thereby limiting the movement of the casing 4 inside the inner annular grooves of the bottom stop 3.

The first and second intermediate thrust elements 6 are two cylindrical elements, the first of which is placed between the first section of the casing 4 and the casing 1 of the column head of the conductor, and the second is located between the first section of the casing 4 and the casing 2 of the casing.

In this case, the intermediate stop elements 6 are fixed relative to the housing 4 by means of toothed profiles made therein, corresponding to the tooth profiles of the longitudinal sectors of the collet of the first section of the housing 4. Additionally, the stop elements 6 are fixed relative to each other, and also relative to the housing 4 by means of fixing pins 10.

The housing 4, the intermediate stop elements 6, the upper stop 7 are made with the possibility of linear movement along the longitudinal axis of the non-metallic sealing element.

Between the first row of segments and the second row of segments of the collet, which is the first section of the housing 4, the end element of the upper stop 7 is placed, whereby the specified collet is fixed in the expanded position and the intermediate stop elements 6 are blocked from moving relative to the housing 4.

In the position in which due to the compression of the non-metallic seals 5, they are secured to the housings 1 and 2 of the column head of the conductor string and the casing suspension, the intermediate stop elements 6 are fixed relative to the housing 4 by means of a toothed profile. While the upper stop 7 is fixed from moving relative to the intermediate thrust elements 6 by means of shear elements 11.

When deactivating a non-metallic sealing element after the destruction of the shear elements 11, the movement of the upper stop 7 relative to the intermediate stop elements 6 is limited by means of the guide pins 12.

To activate the non-metallic sealing element, that is, compressing the non-metallic seals 5 to ensure that these non-metallic seals 5 fit to the bodies 1 and 2 of the column head of the conductor string and the casing suspension, when moving the body 4, the intermediate stop elements 6 and the upper stop 7, the third section of the body 4 moves in the inner annular groove of the lower stop 3, overcoming the force arising from the compression of non-metallic seals 5.

For a given movement of the housing 4 by an amount equal to the width of the spring ring 8, in the inner annular groove of the lower stop 3, sufficient to compress non-metallic seals 5, ensuring their fit to the housings 1 and 2 of the column head of the conductor string and casing suspension and sealing, the spring ring 8 moves into the longitudinal recess of the third portion of the housing 4 and prevents the reverse movement of the housing 4, while maintaining compression of the non-metallic seals 5.

If it is necessary to deactivate the non-metallic seals 5, move the upper stop 7 away from the non-metallic seals 5, destroying the shear elements 11, so the deactivation force depends on the choice of the number of shear elements 11 (from 2 to 10). The movement of the upper stop 7 relative to the intermediate stop elements 6 is limited by the guide pins 12, but enough to remove the end element of the upper stop 7 from the space formed by the first and second rows of collet segments of the first section of the housing 4.

After this extraction, the first and second rows of collet segments of the first section of the housing 4 are able to contract from the forces of non-metallic seals 5. When compressing the first and second rows of collet segments of the first section of the housing 4, they disengage from the gear profile of the intermediate stop elements 6, which Allows 5 non-metallic seals to expand.

Thus, the proposed non-metallic sealing element allows to increase the reliability of activation by limiting the minimum compressive force of non-metallic seals (for example, 100 tons) and fixing it at this level by restricting the movement of elements compressing non-metallic seals.

It should be understood that the invention is limited only by the scope of the claims. Modifications and improvements to the above described embodiments of the present invention without departing from the scope of the claims are apparent to those skilled in the art. The preceding description is provided as an example only and is not subject to any restrictions. Thus, the scope of the present technology is limited only by the scope of the attached claims.

Claims (13)

1. Non-metallic sealing element for sealing the annular space between the casing suspension housing and the conductor casing column head housing, comprising a lower stop with an inner annular groove located in a cavity formed by an annular protrusion made along the perimeter of the outer surface of the casing suspension housing between the casing suspension housing and the casing of the column head of the conductor, while the portion of the lower stop adjacent to the casing of the column head of the conductor, contains grooves made with the possibility of placing bounding segments; a housing containing the first, second and third sections; an upper stop comprising an end member; first and second intermediate thrust elements; first and second non-metallic seals; moreover, the first section of the housing contains an inner recess, forming a space for accommodating the end element of the upper stop, and is a collet containing the first row of segments made with the possibility of gearing with the first intermediate stop element, and the second row of segments made with the possibility of gearing with the second intermediate thrust element; the second section of the casing is made of a thickness substantially equal to the width of the inner annular groove of the lower stop, while the first non-metallic seal is placed between the second section of the casing and the casing of the column head of the conductor, and the second non-metal seal is placed between the second section of the casing and the casing of the casing; the third section of the housing contains an external groove made with the possibility of fixing the spring ring in the initial position, and a longitudinal recess made with the possibility of fixing the housing relative to the lower stop by placing in the said recess part of the limiting segments protruding from the grooves of the lower stop to ensure fit; the first and second intermediate stop elements are made with the possibility of fixing relative to each other, as well as the housing by means of fixing pins; moreover, the housing, the intermediate stop elements and the upper stop are arranged to linearly move from the initial position to the working position, ensuring the movement of the spring ring from the groove into the longitudinal recess of the third section of the housing and activation of non-metallic seals; the upper stop is made with the possibility of linear movement when the shear elements are destroyed by an amount limited by the guide pins from the position in which the end element of the upper stop is located in the inner recess of the first section of the housing to the position in which the end element of the upper stop is removed from the inner recess the first section of the housing, thus providing a displacement of the first and second rows of segments of the collet of the first section of the housing towards each other and the movement of the intermediate thrust e elements to ensure the deactivation of non-metallic seals. 2. Non-metallic sealing element according to claim 1, characterized in that the non-metallic seals are made of rubber, elastomer or other elastic material.

Images