RU2703892C1 - Riser connection assembly - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: invention relates to connection unit of riser for connection of separate vertical connections in offshore oil and gas plants. More specifically, the present invention relates to a connection system of a riser, which can be used in access systems in a well and in blowout prevention equipment of drilling systems. Riser coupling assembly for tight connection of the first riser link and the second riser link, comprising a nut, a locking sleeve and a collet, mounted on the second riser link; collet fitted between second connection section of second riser link and locking sleeve; between nut and locking bushing there is a thread providing possibility of nut rotation relative to locking bushing and translational movement of locking bushing relative to longitudinal axis of riser links at nut rotation, collet is made with possibility of tight connection of the first connecting section and the second connecting section to each other at specified translational movement of the locking bushing.

EFFECT: technical result consists in providing fast and reliable connection of riser sections.

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Description

FIELD OF THE INVENTION

The present invention relates to a riser connector assembly for connecting individual vertical joints in offshore oil and gas installations. More specifically, the present invention relates to a riser connection system that can be used in well access systems and blowout preventer systems.

BACKGROUND

The riser connection unit is supposed to be used for installation and dismantling of riser links, connection of riser links, completion and capital repair of wells, maintenance of wells, links of the sea riser or sea riser, as well as on adapters of equipment connected to the riser in the above systems.

The prior art sources that disclose various designs of the riser connector assembly. In particular, in the source US 10041618, publ. 08/07/2018, the riser connecting node is described, connecting the first riser link with the second riser link. The known connecting unit comprises a plurality of clamping segments that are distributed around the perimeter of the end of the second pipe and have a connected part and a movable part, the connected part and the movable part having segment clamping profiles facing the pipe clamping profiles, the movable part being rotatable around the rotatable part in the radial direction between the internal clamping position and the outer free position; a thrust sleeve located on the periphery of the second pipe and having a stop protruding in the axial direction, under which there is a portion of the connected part of the clamping segments and under which the rotary part is located; a clamping sleeve located on the periphery of the first pipe and having an axial protrusion under which a portion of the movable part of the clamping segments is located when the clamping segments are in the clamping position.

The disadvantages of the known connector are, first of all, the complexity of the design and the complexity of using the known connecting node.

In addition, the prior art source is known to US 4265470, publ. 05/05/1981, revealing a connecting node for connecting two sections of riser pipes, containing a collet surrounding these sections and an engaging shoulder on one of the said sections, and having a plurality of petals with internal protrusions interacting with external protrusions on another section, while connecting the node is sufficiently preloaded. The circlip and locking nut are used to hold the collet of the fingers in the engaged position. In this case, the riser pipe section, relative to which the collet engagement is provided, has a thread. In addition, the connection assembly according to US 4,265,470 comprises a locking nut having a thread on its inner surface, by which it engages with a thread on a riser pipe section with respect to which the collet is engaged. When the collet engages with the pipe section, a snap ring is put on its petals, and a lock nut is put on the thread on the pipe section to hold the collet petals in this position.

Thus, in the well-known source US 4265470 the following features are disclosed that coincide with the features of the proposed technical solution: collet and locking nut. Source US 4265470 B is accepted as the closest analogue.

In the analogue of US 4265470, the connection unit for connecting the riser links, the threaded connection between the nut and the pipe section essentially ensures the connection of the pipe sections to each other and therefore experiences the greatest during operations with risers, which leads to the appearance of a stress concentration in this zone, and, therefore, to the possible risk of damage to this connection during operation. One of the significant drawbacks of the solution known from US 4,265,470 is that the threaded connection between the nut and the pipe section is subjected to stresses, such as the bending moment of the riser and the total weight of the riser.

Also known source is US 4662785, publ. 05/05/1987, in which the connecting unit of the riser used in the subsea hydrocarbon production system is disclosed, comprising a collet, the full engagement of which is achieved due to the fact that the external locking sleeve is pushed onto the collet petals by the thread between the collet and the locking sleeve.

Common drawbacks for existing analogues is the need to use a special tool (slider) to connect and disconnect riser links from the connection, which can lead to risks in the absence or failure of a special tool.

SUMMARY OF THE INVENTION

The present invention is the provision of a connecting node for connecting facing each other and coaxially located pipe ends with a reliable connection. Other useful accomplished tasks are disclosed in the following general description and in the detailed description of embodiments.

According to one embodiment, a riser connection assembly is provided for sealing the first riser link and the second riser link having substantially circular cross-sections, comprising a coaxially arranged first connecting section, integrally formed with the first riser link, and a second connecting section, made integrally with a second riser link, a nut mounted on the second connecting section of the second riser link; a locking sleeve mounted on the second connecting section of the second riser link, a collet installed between the second connecting section of the second riser link and the locking sleeve; moreover, the nut and the locking sleeve are interconnected by a threaded connection so that the nut can rotate relative to the locking sleeve, and the locking sleeve is made with the possibility of translational movement relative to the longitudinal axis of the riser links when the nut is rotated, the collet is made with the possibility of tight connection of the first connecting section and the second connecting section between by itself with the indicated translational movement of the locking sleeve.

At the abutting ends of the first connecting section and the second connecting section, respectively, a first peripheral protrusion and a second peripheral protrusion having the same diameter can be formed.

The second connecting section may have a third peripheral protrusion on which the platform is formed, and a diameter increasing in the direction from the second peripheral protrusion to the third peripheral protrusion.

The riser connection unit may comprise a washer configured to be installed on a site of a third peripheral protrusion, the nut being configured to be mounted on the washer.

The technical result of the invention is to enable fast and reliable connection of the riser sections.

Typically, the presence of a threaded connection that carries heavy loads during operations with risers leads to the appearance of a stress concentration in these zones, which leads to possible damage to the connecting unit during operation. In the proposed technical solution, the threaded connection is not subjected to stresses, such as the bending moment of the riser, the total weight of the riser, due to the use of a combination including a collet, a nut and a locking sleeve installed between them, made with the possibility of translational movement during rotation of the nut and pressing the collet to the docked sections riser. Due to this, the load, for example, from the bend of the riser is redistributed to the collet and then to the locking sleeve and the thread connecting the locking sleeve and nut.

Additionally, it is possible to connect and withdraw from the connection of riser links using conventional tools in case of breakage / absence of a specialized tool (spider).

In the context of the present description, the words “first”, “second”, “third”, etc. used in the form of adjectives solely to distinguish the nouns to which they relate from each other, and not for the purpose of describing any specific relationship between these nouns. So, for example, it should be understood that the use of the terms “first protrusion” and “third protrusion” does not imply any order or sequence between the protrusions, nor does their use (in itself) imply that a certain “second protrusion” is necessary must exist in a given situation.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a detailed description of the invention with reference to the drawings, where

in FIG. 1 is a cross-sectional view of a riser connection assembly in an open position;

in FIG. 2 is a cross-sectional view of a riser connector assembly in a first intermediate position;

in FIG. 3 is a cross-sectional view of a riser connecting unit in a second intermediate position;

in FIG. 4 is a cross-sectional view of a riser connection assembly in a closed position.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 schematically depicts a riser 1 connector assembly according to a non-limiting embodiment of the invention. The riser assembly 1 is designed to seal the first link 2 of the riser and the second 3 link of the riser. The riser links 2, 3 are tubes of substantially circular cross section.

Each link 2, 3 of the riser contains the first connecting section 4, made as a whole with the first link 2 of the riser, and the second connecting section 5, made as a whole with the second link 2 of the riser. At the junction of the first connecting section 4 and the second connecting section 5, the peripheral first protrusion 6 and the second protrusion 7 of the same diameter are formed respectively at the abutting ends of the sections.

The first connecting section 4 is a mate for the second connecting section 5, and the second connecting section 5 has a complex configuration and a variable diameter that increases in the direction from the second peripheral protrusion 7 to the third peripheral protrusion 8 having the largest diameter. Thus, the diameter D1 of the first peripheral protrusion 6 is equal to the diameter D2 of the second peripheral protrusion 7, and the diameter D3 of the third peripheral protrusion 8 exceeds the diameters D1 and D2. On the third peripheral protrusion from the side facing the first section there is a platform 9, also extending peripherally, that is, around the entire circumference of the third peripheral protrusion 8. A washer 10 is installed on the platform 9 to accommodate the nut 11, while the washer protrudes relative to the platform 9 around the entire periphery and the nut 11 has a protrusion 12, the diameter of which exceeds the diameter of the nut 11 as a whole in the part where the nut 11 rests on the washer 10.

The nut 11 is mounted on the washer 10 in such a way that it peripherally extends along the outer edge of the washer 10, while the edge of the washer 10 and the protrusion 12 of the nut 11 have approximately the same diameter, due to which the nut 11 is fixed relative to the washer 10 by means of an annular bracket 13, covering the periphery of the edge the washers 10 and the protrusion 12 of the nut 11. The nut 11 is installed relative to the washer 10 and the bracket 13 without interference to ensure rotation of the nut 11 relative to the longitudinal axis of the riser 1.

As is clear from the above description and drawing, the nut 11 is mounted on the second connecting section 5, the locking sleeve 14 and the collet 15 are also installed there. The collet 15 is installed between the second connecting section 5 and the locking sleeve 14. The nut 11 and the locking sleeve 14 are interconnected by a threaded connection with the possibility of rotation of the nut relative to the locking sleeve 14. The inner part of the nut 11 is threaded, and the counter thread is on the outer part of the locking sleeve 14 (threads are not shown in the drawings).

The inner parts of the petals 16 of the collet 15 are made with a first recess 17 having a shape corresponding to the shape of the joined first peripheral protrusion 6 and the second peripheral protrusion 7. According to a non-limiting embodiment, the shape of the joined protrusions 6, 7 is toroidal and convex, and the shape of the recesses of the petals 16 of the collet 15, respectively, is concave. However, it will be apparent to those skilled in the art that this may be another suitable form.

As already mentioned above, the second connecting section 5 has a complex configuration and a variable diameter. According to a non-limiting embodiment, the second connecting section 5 has one cylindrical section extending from the first peripheral protrusion 6 by a certain distance, and then turning into a relatively smooth bend with increasing diameter from the first peripheral protrusion 6 to the platform 9, this transition corresponding to the configuration of the inner part of the collet 15 in the area of its base 18. As can be seen from the drawings, the inner part of the collet 15 also has a smooth bend corresponding to the bend of the second connecting section 5.

The outer surface of the petals 16 of the collet 15 has a slight recess 19 in the place where the locking sleeve 14 exerts pressure on the petals 16 of the collet 15. At the base 18 of the collet 15 has a smooth bend corresponding to a smooth bend of the second connecting section 5 in the transition zone from diameter D2 to diameter D3.

In addition, the shape of the outer surface of the base 18 of the collet 15 corresponds to the shape of the inner surface of the locking sleeve 14 in the zone of contact with each other. The outer surface of the collet 15 in the contact zone with the locking sleeve 14 has a first conical surface 20 with a first taper angle and then passes into the second conical surface 21, which extends from the base 18 of the collet to the second recess 19. The first conical surface 20 and the second conical surface 21 are inclined in different directions.

The inner surface of the locking sleeve 14 at one end thereof in the area of contact with the base 18 of the collet 15 also has a third conical surface 22 with a third taper angle, which passes into the fourth conical surface 22 with a fourth taper angle. The first conical surface 20 of the outer surface of the collet 15 during operation is in contact with the third conical surface 22 of the inner surface of the locking sleeve 14 and the cylindrical surface 21 of the outer surface of the collet 15 during operation is in contact with the fourth conical surface 22 of the inner surface of the locking sleeve 14. Similar to collet 15, the locking sleeve 14, the third conical surface 22 and the fourth conical surface 23 are inclined in different directions.

The locking sleeve 14 on its inner side has a fourth peripheral protrusion 24 at its other end, opposite to where there is a third conical surface 22. The fourth peripheral protrusion 24 is designed to contact the recess 29 in the outer surface of the petals 16 of the collet 15 during operation of the riser connecting node .

The connecting node riser operates as follows.

On the first link 2 of the riser 1 is suspended, for example, on a hanging plate or suspension key in the rotary table of a drilling platform or vessel (not illustrated in the drawings). The first link 2 risers lower on the elevator of the oil rig in a vertical position. Thus, the first link 2 of the riser is lowered to the docking of its first connecting section 4 with the second connecting section 5 by their peripheral protrusions 6, 7. The contact surfaces of the first connecting section 4 with the second connecting section 5 are shown by arrows in FIG. one.

When the nut 11 is rotated, the locking sleeve 14 moves progressively upward and exerts pressure on the petals 16 of the collet 15, which, under the influence of this pressure, are closed on the first joined peripheral protrusion 6 and the second peripheral protrusion 7, covering them. Thus, when the nut 11 is rotated, the inner surface of the locking sleeve 14 compresses the petals 16 of the collet 15, which leads to the locking of the petals of the collet 15 on the second connecting section 5 of the second riser link and on the mating first connecting section 4 of the first riser link 2.

In FIG. 1 shows the connection unit in the open position. In this position, the locking sleeve 14 is in contact with its third conical surface 22 with the first conical surface 20 of the collet 15 in a small area.

In FIG. 2-4 illustrate how the closed position of the proposed riser connector assembly is successively achieved. In FIG. 2 shows that the contact area of the third conical surface 22 with the first conical surface 20 has increased, and by means of the locking sleeve 14, sufficient pressure was applied to the petals 16 of the collet 15 to bring the petals 16 to the first and second peripheral protrusions 6, 7. The fourth peripheral protrusion 24 the locking sleeve approaches the second recess 19 on the outside of each petal 16 of the collet 15.

In FIG. 3 it can be seen that the third conical surface 22 is completely in contact with the first conical surface 20, while under the pressure that the locking sleeve 14 exerts on the base 18 of the collet 15 in the area of the first conical surface, the petals of the collet 15 are as close as possible and are joined to the first and second peripheral protrusions 6, 7.

In FIG. 4 illustrates the fully closed position of the riser connector assembly. In this position, the locking sleeve 14 is in contact with a part of its fourth conical surface 23 with the second conical surface 21 of the collet 15. In this case, under the pressure exerted by the locking sleeve 14 on the second conical surface 21, the petals 16 of the collet 15 are pressed against the joined first and second peripheral protrusions 6 7. In this case, the locking sleeve 14 extends significantly upward relative to the nut 11. For clarity, in FIG. 4 arrows show the contact surfaces of the first link 2 of the riser and the second link 3 of the riser.

Closing and opening of the proposed connecting node can be carried out using a special tool similar to a spider, or using a wrench, for example, in the absence of a special tool on the drilling platform or in case of failure.

The assembly of the connecting node riser 1 is carried out in the following sequence. A washer 10 is installed on the pad 9, then a collet 15 is placed around the second connecting section, then a locking sleeve 14 is placed around the collet 15 with the nut 11 screwed onto it. Then, the nut 11 and the washer 10 are fastened around the periphery by an annular bracket 13, as a result of which the nut 11 remains fixed relative to the washer 10 during rotation relative to the axis of the riser links, while the locking sleeve 14 moves progressively upward in the direction of the first link 2 of the riser.

It should be understood that the present description is not intended to determine the scope of protection of the proposed technical solution, the purpose of the description is to provide an understanding of the proposed technical solution. The described embodiment is not exhaustive, and it will be apparent to those skilled in the art that other embodiments of the proposed technical solution are possible.

Claims (13)

1. A riser connection assembly for tightly connecting a first riser link and a second riser link having substantially circular cross sections, comprising coaxially located the first connecting section, made as a whole with the first link of the riser, the second connecting section, made as a whole with the second link of the riser, a nut mounted on the second connecting section of the second riser link; a locking sleeve mounted on the second connecting section of the second riser link, a collet mounted between the second connecting section of the second riser link and the locking sleeve; moreover, the nut and the locking sleeve are interconnected by a threaded connection with the possibility of rotation of the nut relative to the locking sleeve, and the locking sleeve is made with the possibility of translational movement relative to the longitudinal axis of the riser links during rotation of the nut, the collet is made with the possibility of tight connection of the first connecting section and the second connecting section to each other with the specified translational movement of the locking sleeve. 2. The riser connecting unit according to claim 1, characterized in that at the abutting ends of the first connecting section and the second connecting section, respectively, a first peripheral protrusion and a second peripheral protrusion having the same diameter are formed. 3. The riser connection assembly according to claim 2, wherein the second connection section has a third peripheral protrusion on which a platform is formed, and a diameter increasing in a direction from the second peripheral protrusion to the third peripheral protrusion. 4. The riser connection assembly according to claim 1, comprising a washer configured to be installed on a site of a third peripheral protrusion, the nut being configured to be mounted on the washer.

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