RU2702488C1 - Collet connector - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, in particular to devices for wellhead equipment. Disclosed is a collet connector comprising a column head housing and a housing of a wellhead tree gate valve unit configured to be installed between the outer surface of the housing of the column head and the inner surface of the housing of the wellhead tree gate valve block, as well as with possibility of installation in annular grooves made at ends of housing of column head and body of unit of gate valves of wellhead, main ring metal seal. Said connector comprises a collet chuck configured to be installed inside the housing of the wellhead tree gate valve and comprising a plurality of longitudinal sectors, wherein each longitudinal sector of the collet chuck comprises an upper end element made so as to enter the annular recess made on the wellhead tree block frame body inner surface, and lower end element containing annular grooves corresponding to annular grooves made on inner surface of column head body. Collet connector further comprises a mandrel configured to linearly move between an open position in which a gap between the inner surface of the casing of the column head and the lower end elements of the longitudinal sectors of the collet chuck is maintained, and a closed position, in which annular grooves of lower end elements of longitudinal sectors of collet chuck engage with annular grooves of inner surface of housing of column head, thus providing connection between housing of column head and housing of block of gate valves of wellhead. Besides, mandrel comprises mechanism for adjustment of outer diameter. Said mechanism comprises: a split ring configured to be mounted on a lower part of the mandrel, wherein the split ring consists of sectors the inner surface of which is conical; a lid configured to lock sectors of the split ring; as well as a bushing configured to move in axial direction. At that, outer surface of the bushing is conical, with a slope opposite to the slope of the split ring, and part of thrust surfaces of the bushing extends beyond the cover.

EFFECT: high degree of reliability and tightness of connection at simultaneous reduction of weight and size characteristics and simplification of processes of assembly and dismantling of equipment at wells.

3 cl, 3 dwg

Description

The present invention relates to the oil and gas industry, in particular, to wellhead equipment devices, in particular, to devices for connecting a column head housing and a housing of a wellhead Christmas tree gate valve block.

BACKGROUND

The prior art discloses a wellhead device disclosed in document RU 2118441 C1 (published on 08.27.1998) containing wellhead connecting elements in the form of a pipe head adapted to be connected to the column head cross by a mounting cone and column head, valves and o-rings.

The known device of the wellhead equipment of the wells has insufficient sealing quality, a large elemental base and is not reliable enough during operation.

It is also known a device for wellhead equipment containing connected elements in the form of a pipe and column head, valves and o-rings (disclosed in RU 2171357 C2, published July 27, 2001).

The pipe head of the known device is made with the possibility of connection with the cross of the column head along the landing cone. The known device is equipped with additional elastic rings and quick couplings in the form of a connecting threaded ring with supporting flanges. Additional rings are installed in annular grooves made at the ends of the connected elements of the device. Support flanges are made on the inner surface of the connecting threaded ring for interaction with split annular support liners. The liners are installed in annular grooves made on the outer surfaces of the connected elements of the device. An elastic sealing ring, a sleeve with side openings, a second elastic sealing ring and a pressure ring are installed sequentially in the annular gap between the cylindrical surfaces of the spider of the column and pipe head and on the collar of the pipe head. The pressure ring interacts with the union nut. The union nut forms a threaded pair with the cross of the head column.

The disadvantages of the known device include the need for time-consuming screwing of joints made in the form of threaded rings with supporting collars. In addition, this connection requires an increased margin of safety, due to the need to ensure the required level of reliability of the connection, perceiving tensile force and bending moment during installation and maintenance of equipment.

Also known from the prior art is the device disclosed in US 9169710 B2 (published April 30, 2015) related to the wellhead connector. A known connector comprises a housing, a piston and a plurality of collets. The housing of the known connector contains an end configured to connect to the first connected element, and a cavity configured to receive the second of the connected elements. The piston is movable axially in the connector housing. Collets are mounted relative to the body of the connector, adjacent to the piston, and are movable in the radial direction relative to it. Collets have a profile along their outer surface corresponding to the profile of the piston located along its inner surface. The collets further comprise an engagement profile located along their inner surface and configured to mesh with the second of the joined members so that the collets clamp the second of the joined members.

The disadvantages of the device known from the document US 9169710 B2, is the large elemental base and design complexity, which leads to a significant complication of the assembly operation of the device, as well as a large number of bolted connections, which entails a decrease in the degree of reliability of the device.

SUMMARY OF THE INVENTION

The technical problem solved by the creation of the claimed invention is to create a collet connector for connecting the body of the column head and the housing of the block of valves of the wellhead Christmas tree, providing an increased level of reliability and tightness while reducing weight and size characteristics and simplifying operations of assembly, installation and dismantling of equipment in wells.

The technical result achieved by the implementation of the invention is to increase the degree of reliability and tightness of the connection while reducing weight and size characteristics and simplifying the assembly, installation and dismantling of equipment in wells.

The claimed technical problem and the specified technical result, respectively, are solved and achieved by the fact that the collet connector comprises a column head housing and a housing of a valve block of a wellhead Christmas tree made with the possibility of installing a sealing between the outer surface of a housing of a column head and an inner surface of a housing of a block of valves of a wellhead Christmas tree, as well as the ability to install in annular grooves made at the ends of the column head housing and the housing of the block of valves of the wellhead tree, the main annular allic seal, while the collet connector contains a collet chuck made with the possibility of installing inside the housing of the block of valves of the wellhead tree and containing many longitudinal sectors, each longitudinal sector of the collet chuck contains an upper end element made so as to enter into an annular recess made on the inner surface of the housing of the valve block of the wellhead tree, and the lower end element containing annular grooves corresponding to annular grooves made on the inner surface of the column head housing, the collet connector further comprising a mandrel configured to linearly move between an open position in which a gap is maintained between the inner surface of the column head housing and the lower end elements of the longitudinal sectors of the collet chuck, and a closed position in which the annular grooves lower end elements of the longitudinal sectors of the collet chuck are engaged with the annular grooves of the inner surface of the housing onnoy head, thus providing the connection between the wellhead housing and the unit housing wellhead tree valves.

The engagement of the annular grooves of the lower end elements of the longitudinal sectors of the collet chuck with the annular grooves of the inner surface of the column head housing provides an internal connection of the column head housing and the housing of the wellhead valve block of the Christmas tree, and this connection only accepts tensile forces during operation, installation and maintenance of equipment; the forces acting on the connection when a bending moment is applied are perceived by the body of the valve block of the wellhead tree. Due to the specified spacing of the elements that perceive the tensile force and bending moment, an increase in the degree of reliability and tightness of the connection is achieved while reducing weight and size characteristics.

The tightness of the connection is ensured by installing the main annular metal seal between the ends of the column head housing and the body of the gate valve block of the Christmas tree, as well as the non-metallic or combined non-metal and metal seal between the outer surface of the column head housing and the inner surface of the body of the gate valve block of the Christmas tree.

In addition, due to the lack of flange connections, as well as the absence of the need for screwing connections through the use of a collet chuck, simplification of the processes of installation and dismantling of equipment in wells is achieved.

Thus, the totality of the features of the invention in the preferred embodiment, disclosed above and presented in the claims, ensures the achievement of the claimed technical result.

BRIEF DESCRIPTION OF THE DRAWINGS

The above advantages of the invention will become more apparent from the following description of a preferred embodiment, given with reference to the accompanying drawings, in which:

- in FIG. 1 shows a collet connector when the mandrel is in the open position in accordance with a preferred embodiment of the invention,

- in FIG. 2 shows a collet connector when the mandrel is in a closed position in accordance with a preferred embodiment of the invention,

- in FIG. 3 depicts a mechanism by which an external perimeter of a mandrel of a collet connector is fitted in accordance with a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Next, with reference to the accompanying drawings, a collet connector according to a preferred embodiment of the invention is described.

In FIG. 1 and 2 schematically depict a collet connector comprising a housing (1) of a column head and a housing (2) of a valve block of a wellhead Christmas tree. A seal (3) is installed between the outer surface of the casing (1) of the column head and the inner surface of the casing (2) of the valve block of the wellhead tree. In one embodiment, the seal (3) is non-metallic. In another embodiment of the invention, the seal (3) is made of a combined non-metallic and metallic.

An annular groove (4) and an annular groove (5), respectively, are made at the ends of the housing (1) of the column head and housing (2) of the valve block of the wellhead tree. In these annular grooves (4) and (5), a main annular metal seal (6) is installed.

The collet connector comprises a collet chuck (7) mounted inside the housing (2) of the wellhead Christmas tree gate valve block. The collet chuck (7) consists of many longitudinal sectors (8). Each longitudinal sector (8) contains an upper end element (9) and a lower end element (10).

The upper end element (9) is included in the annular recess (11) of the inner surface of the housing (2) of the wellhead Christmas tree gate valve block.

The lower end element (10) contains annular grooves (12) corresponding to the annular grooves (13) made on the inner surface of the housing (1) of the column head.

The collet connector also includes a mandrel (14) configured to linearly move between the open position (illustrated in FIG. 1) and the closed position (shown in FIG. 2).

In the open position between the inner surface of the housing (1) of the column head and the lower end elements (10) of the longitudinal sectors (8) of the collet chuck (7), a gap is maintained.

In the closed position, the annular grooves (12) of the lower end elements (10) of the longitudinal sectors (8) of the collet chuck (7) engage with the annular grooves (13) of the inner surface of the housing (1) of the column head, thus providing a connection between the housing (1 ) the column head and the body (2) of the block of valves of the wellhead Christmas tree.

The housing (2) of the wellhead Christmas tree gate valve block is mounted on the housing (1) of the column head through the main annular metal seal (6). The mandrel (14) is in the open position. Further, by pressing in the mandrel (14), the longitudinal sectors (8) of the collet chuck (7) are compressed, the annular grooves (12) of the lower end elements (10) of the longitudinal sectors (8) of the collet chuck (7) mesh with the ring grooves (13) ) the inner surface of the housing (1) of the column head, thus providing a connection between the housing (1) of the column head and the housing (2) of the gate valve block of the wellhead tree.

The casing (2) of the wellhead Christmas tree gate valve block is fixed on the casing head housing (1) using a descent tool. The descent tool is additionally equipped with a design that provides the ability to create the required design force along the longitudinal axis of the housing (1) of the column head.

Before lowering the body (2) of the block of valves of the wellhead Christmas tree, the mandrel (14) is installed in the open position, the body (2) of the block of valves of the wellhead Christmas tree is lowered to the wellhead and after centering the column head on the body (1), the tool for lowering moves the mandrel to the closed position.

The mandrel (14) for clamping the collet chuck (7) is fixed from arbitrary movement by the subsequent installation of the suspension of the tubing.

To ensure the required preload force of the main annular metal seal (6), the external perimeter of the mandrel (14), which is in contact with the longitudinal sectors (8) of the collet chuck (7), is adjusted.

Said fitting is realized by the mechanism depicted in FIG. 3.

The lower part of the mandrel (14) is machined to fit a split ring (15), consisting of sectors that are held on the mandrel body (14) by a set of ring springs (16). The inner surface of the sectors of the split ring (15) is conical. From below, the sectors of the split ring (15) are fixed by a cover (17), which is attached to the mandrel (14) with screws (18).

Thus, when operating a collet connector equipped with the aforementioned mechanism, the axial movement of the sectors of the split ring (15) is excluded. The outer surface of the sleeve (19) is made conical, with a slope opposite to the slope of the split ring (15).

Changing the outer diameter of the mandrel (14) is done by moving the sleeve (19) in the axial direction. The movement is carried out using a nut (20) mounted on the threaded part of the cover (17).

The sleeve (19) is made in such a way that part of the thrust surfaces of the sleeve (19) protrudes beyond the cover (17) through the grooves provided by the mechanism. Thus, it is possible to adjust the outer diameter of the mandrel (14) without the need for dismantling and disassembling it.

The adjustment of the required pressing force of the mandrel (14) is carried out in the following sequence:

install the housing (2) of the valve block of the wellhead tree on the housing (1) of the column head,

set the mandrel (14) in the closed position,

fix the closing force,

set the mandrel (14) in the open position,

dismantle the housing (2) of the valve block of the wellhead tree from the housing (1) of the column head,

move the mandrel (14) to the closed position,

calculate to determine the direction of rotation of the nut (20), as well as the number of revolutions of rotation,

using the nut (20), move the sleeve (19) in the desired direction, translate the mandrel (14) to the open position.

It should be understood that the preferred embodiment of the invention described above by way of example does not limit the scope of the present invention. After reviewing the present description, those skilled in the art can propose many changes and additions to the described embodiments, all of which will fall within the scope of patent protection of the invention defined by the following claims.

Claims (3)

1. Collet connector for connecting the housing of the column head and the housing of the block of valves of the wellhead tree, comprising the housing of the column head and the housing of the block of valves of the wellhead Christmas tree made with the possibility of installing between the outer surface of the housing of the column head and the inner surface of the housing of the block of valves of the wellhead Christmas tree the possibility of installing in the annular grooves made at the ends of the column head housing and the housing of the block of valves of the wellhead Christmas tree, the main annular metal seal; collet chuck made with the possibility of installing inside the housing of the block of valves of the wellhead Christmas tree and containing many longitudinal sectors, each longitudinal sector of the collet of the cartridge contains an upper end element made so as to enter an annular recess made on the inner surface of the housing of the block of valves of the wellhead tree, and a lower end member comprising annular grooves corresponding to annular grooves formed on the inner surface of the column head housing; moreover, the collet connector further comprises a mandrel configured to linearly move between the open position, in which a gap is maintained between the inner surface of the column head housing and the lower end elements of the longitudinal sectors of the collet chuck, and the closed position, in which the annular grooves of the lower end elements of the longitudinal sections of the collet chuck mesh with the annular grooves of the inner surface of the housing of the column head, thus providing a connection between the body of the column head and the body of the block of valves of the wellhead tree; wherein the mandrel comprises a mechanism for adjusting the outer diameter, comprising a split ring configured to be mounted on the lower part of the mandrel, the split ring consisting of sectors whose inner surface is tapered; a cover configured to fix sectors of the split ring; and also the sleeve, made with the possibility of movement in the axial direction, and the outer surface of the sleeve is made conical, with a slope opposite to the slope of the split ring, and part of the thrust surfaces of the sleeve extends beyond the cover. 2. A collet connector according to claim 1, characterized in that the seal is non-metallic. 3. The collet connector according to claim 1, characterized in that the seal is made of a combined non-metallic and metal.

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