SUPPORT FOR RISERS AND METHOD FOR COUPLING AND UNCOUPLING

Abstract

The present invention addresses to a system for supporting the tension load of the riser, this component with the primary function of supporting the risers, where the riser support mechanism is an integral part of the upper cone, thus eliminating the need to install slips by the shallow dive, and, also avoiding that the locking mechanism is an integral part of the Top Termination of the Riser (L). There is a minimal number of moving parts, which favors the maintainability of the system. In addition, if maintenance is required, the size and weight of the components are compatible with diving operations. For pull-in operations, it is anticipated that the slips will return to their working position only by the action of the force of gravity. In the case of pull-out, the concept of automated slip retraction mechanism was developed. A new Top Termination of the Riser (TTR) (L) geometry is also proposed, aiming at its simplification, in which, in addition to considering the locking mechanism as an integral part of the upper cone of the Support Pipe, there is the elimination of moving components for stabilization of its side movement (a function formerly performed by the locking ring or by the gap compensator).

Claims

1. A SUPPORT FOR RISERS, characterized in that it comprises: A riser interconnection component in at least one pipe Support with a rigid riser support mechanism as an integral part of the upper cone (k); A geometrically modified Top Termination of the Riser (L) with elimination of moving components.

2. THE SUPPORT FOR RISERS according to claim 1, characterized in that the upper cone (k) of the Support Pipe comprises an axle (1), a fork (2), slips (3), wear bushing (4), support for camera (5), cone eyelet (6), antifouling pins (7), union pin (8), rail (9), pin for retraction bar (10), clamp (11), eyelet for slip retraction mechanism tool (13), backup eyelet for slip retraction (16).

3. THE SUPPORT FOR RISERS according to claim 1, characterized in that the Top Termination of the Riser (L) comprises a riser pre-alignment profile (a), a slips support region (b), a spherical geometry region (c) for initial TTR entry (L), an hourglass-shaped region (d) for minimization of pull-in forces, a conical surface for gap suppression & final alignment (e), a cylindrical surface (f) for transmission of shear force to the Support Pipe and a stiffness transition device (g) between the riser extension and the TTR (L).

4. THE SUPPORT FOR RISERS according to claim 3, characterized in that it comprises a curvature stiffener (i), replacing the components (g) and the riser extension (h) in order to support a flexible riser.

5. THE SUPPORT FOR RISERS according to claim 2, characterized in that the axle (1) has a groove indicating sufficient retraction of the slip (3).

6. THE SUPPORT FOR RISERS according to claim 2, characterized in that it comprises a slip retraction mechanism bar (12), an axle extender (14) and a tool installed and used to retract the slips (15).

7. THE SUPPORT FOR RISERS according to claim 2, characterized by the slips (3) being rounded/faired on the surface that comes into contact with the pull-in cable.

8. THE SUPPORT FOR RISERS according to claim 2, characterized in that the fork (2) has a hole for installing the retraction tool (pin and bar) (10 and 12).

9. THE SUPPORT FOR RISERS according to claim 2, characterized in that the union pin (8) couples the axle (1), the slip (3) and the fork (2).

10. THE SUPPORT FOR RISERS according to claim 2, characterized in that the wear bushing (4) is the preferred point of contact with the pull-in cable and mitigating wear on the upper cone (k).

11. THE SUPPORT FOR RISERS according to claim 3, characterized in that the riser pre-alignment profile (a) eliminates the risk of overloads in the pull-in system and smoothly aligns the riser in the Support Pipe.

12. THE SUPPORT FOR RISERS according to claim 3, characterized in that the slips support region (b) comprises the surface that effectively supports the tension load of the riser, presenting the angle compatible with the slips (3) of the upper cone (k).

13. THE SUPPORT FOR RISERS according to claim 3, characterized in that the spherical geometry (c) for the entry of the TTR (L) presents spherical geometry, a diameter greater than the slips support edge (b) and is the main surface of initial contact between the top termination of the riser (L) and the support.

14. THE SUPPORT FOR RISERS according to claim 3, characterized in that the spherical geometry (c) for the entry of the TTR (L) eventually acting as a ball joint for the initial entry of the riser.

15. THE SUPPORT FOR RISERS according to claim 3, characterized in that the hourglass-shaped region (d) is located below the spherical region (c) and allows misaligned insertion of the TTR (L).

16. THE SUPPORT FOR RISERS according to claim 3, characterized in that the conical surface for gap suppression (e) suppresses the gap provided by the hourglass-shaped region (d) after the entry of the TTR (L) in the Support Pipe and aligns the TTR (L) with the Support Pipe.

17. THE SUPPORT FOR RISERS according to claim 3, characterized in that the cylindrical surface for transmission of shear force (f) is located below the conical surface for gap suppression (e) and is the last element to come into contact with the Pipe Support.

18. A COUPLING METHOD, characterized in that it has having the following steps: Inserting the Top Termination of the Riser (L) into a Support Pipe in an upward movement; Contacting the spherical geometry of the TTR (L) on the Support Pipe and creating the first torque resistant to entry; Starting contacting the conical surface of the TTR (L) with the Support Pipe; Centering the TTR (L) on the Support Pipe; Touching the TTR (L) in the slips (3) and pushing them upwards together with the slip (3)/fork (2) and axle (1) assembly; Finishing the upward movement of the slip (3)/fork (2)/axle (1) assembly and descending the same by gravity after the end of contact with the TTR (L); Finishing the downward movement of the slip (3)/fork (2)/axle (1) assembly; Lowering the TTR (L) completely and rest it on the slips (3).

19. A METHOD FOR DECOUPLING, characterized in that it has the following steps: Installing the slip retraction mechanism (3): slip retraction mechanism bar (12), axle extender (14) and slip retraction tool (15); Raising the TTR (L) to the over-pull position; Retracting the slip (3)/fork (2)/axle (1) assembly using the unlocking tool (15) acting on the extender (14); Lowering and removing the TTR (L).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be described in more detail below, with reference to the attached figures which, in a schematic way and not limiting the inventive scope, represent examples of the same. In the drawings, there are:

[0032] FIG. 1 illustrating an overview of the upper cone and rigid riser support components;

[0033] FIG. 2 illustrating the section view of the upper cone;

[0034] FIG. 3 illustrating the detail of the slip groove, used as a secondary guide;

[0035] FIG. 4 illustrating the axle (1), fork (2) and slip (3) assembly and detail of the chamfer on the axle;

[0036] FIG. 5 illustrating the detail of the union pin for the coupling between the axle, fork and slip;

[0037] FIG. 6 illustrating the automated retraction mechanism of the slips;

[0038] FIG. 7 illustrating the automated retraction mechanism of the slips;

[0039] FIG. 8 illustrating the geometry of the TTR;

[0040] FIG. 9 illustrating the TTR geometry adapted to support flexible risers;

[0041] FIG. 10 illustrating the beginning of the upward movement of the slip/fork/axle assemblies;

[0042] FIG. 11 illustrating the end of the downward movement of the slip/fork/axle assembly;

[0043] FIG. 12 illustrating the TTR after being pulled, losing contact with the slips;

[0044] FIG. 13 illustrating the total retraction of the slips and consequent removal of the TTR;

[0045] FIG. 14 illustrating the automated retraction mechanism of the slips.

DETAILED DESCRIPTION OF THE INVENTION

[0046] The rigid riser support has the following components: [0047] Axle (1); [0048] Fork (2); [0049] Slip (3); [0050] Wear bushing (4); [0051] Support for camera (5); [0052] Cone eyelet (6); [0053] Antifouling pins (7); [0054] Union pin (8); [0055] Rail (9); [0056] Pin for retraction bar (10); [0057] Clamp (11); [0058] Alternatively, there may be a slip retraction mechanism bar (12), axle extender (14) and slip retraction tool (15) installed for the pull-out step (or, if necessary, for the pull-in); [0059] Eyelet for slip retraction mechanism tool (13); Backup eyelet for slip retraction (16).

[0060] The axle (1) is the component with the primary guide function for the retraction and extension of the slips (3) during pull-in/pull-out operations. Upon observing its geometry, it is noted that its thickest part defines its end-of-stroke position. An eyelet (16) was added in this thicker region to serve as a pulling point for retracting the slips (3). The axle has a groove, easily seen by cameras installed on the support (5) or ROV, which indicates sufficient retraction of the slip (3) to release the TTR (L) in a pull-out operation.

[0061] The slip (3) is an effective component of tension load support of the rigid riser. During pull-in operations, there is contact between the pull-in cable and the slips (3), which retract without resistance. In order to avoid damage to the pull-in cable or to the slip itself (3) in this contact, the surfaces facing the axial direction of the system are rounded/faired.

[0062] In order that side loads do not occur, the rail (9) serves as a secondary guide during the contact with the pull-in cable, as it acts together with the slip groove (FIG. 3) as a reaction surface for side loads, avoiding axle (1) warping and consequent locking of the system.

[0063] The fork (2), an item necessary only for installing the retraction tool, is located between the axle (1) and the slip (3) and has a hole for installing the retraction tool (10 and 12) (pin and bar) for joint retraction of the slips (3).

[0064] The union pin (8) is the component responsible for the coupling between the axle (1), the slip (3) and the fork (2).

[0065] The cone eyelet (6) is the component used to lift the upper cone (k).

[0066] The antifouling pins (7) are the components used to protect against incrustation of the holes in the fork where the retraction tool pins (10) and the respective clamps (11) will enter.

[0067] The wear bushing (4) is the component responsible for mitigating wear on the upper cone (k). During the installation of the rigid riser, the pull-in cable will come into contact with the upper cone (k), which could cause damage to the upper cone (k). The wear bushing (4) is a component whose geometry presents itself as a preferential point of contact with the pull-in cable, and its wear is foreseen in the design and does not impact the structural strength and the functioning of the mechanisms.

[0068] The backup eyelet for slip retraction (16) is the axle eyelet (1) that can be used for its movement in case of failure of the main unlocking system, and the slip retraction tool (15) is coupled to the slip retraction mechanism eyelet (13), which, in turn, is connected to the axle extender (14).

[0069] Aiming at simplification, a new geometry was developed for the TTR (L), as can be seen in FIG. 8, which, in addition to considering the locking mechanism as an integral part of the upper cone of the support pipe (k), there is the elimination of moving components to stabilize its side movement. The new configuration consists of the following regions: [0070] Riser pre-alignment profile (a); [0071] Slip support region (b); [0072] Spherical geometry (c) for initial TTR entry (L); [0073] Hourglass shape (d) for minimization of pull-in forces; [0074] Tapered surface for gap suppression & final alignment (e); [0075] Cylindrical surface (f) for transmission of shear force to the Support Pipe; [0076] Rigidity transition device between the riser and the TTR (L), such as a Flexjoint (illustrative example in the figure), Stressjoint, etc. (g); [0077] Riser extension connected to Flexjoint (h).

[0078] The regions described above describe the TTR (L) solution for rigid riser support. The TTR (L) can be easily adapted to support flexible risers by replacing components (g) and (h) with a curvature stiffener (i), a component typically used to provide protection for flexible risers, as can be seen in FIG. 9.

[0079] The riser pre-alignment profile (a) is the transition region between the small diameter of the TTR flange (L) connected to the tension head for riser pull-in and the slips support region (b), being necessary to carry out a smooth pre-alignment of the riser in the Support Pipe, eliminating the risk of overloads in the pull-in system.

[0080] The slips support region (b) contains the surface that effectively supports the tension load of the riser, presenting the angle compatible with the slips (3) of the upper cone (k). The fundamental premise is that, whatever the demand coming from the riser is, the contact pressure between the TTR (L) and the slips (3) of the upper cone (k) can even be slowed down, but not suppressed to the point that the contact between the top termination of the riser (L) and its support system is ceased.

[0081] The spherical geometry (c) for the entry of the TTR (L), although the first contact region of the TTR (L) with the support pipe is precisely the edge of the slips support region (b), has a larger diameter, thus being the main surface of initial contact between the top termination of the riser (L) and the support. As it is spherical, whatever the installation misalignment, the contact condition of the TTR (L) with the support pipe is quite homogeneous, thus acting as a “ball joint” for the initial entry of the riser.

[0082] The hourglass-shaped region (d) allows a misaligned insertion of the TTR (L) in almost its entire length, allowing the spherical region (c) to effectively act as a ball joint, thus avoiding the appearance of large resistive forces to the pull-in operation. It is located below the spherical region (c), where there is a portion of the TTR (L) with a diameter significantly smaller than the internal diameter of the support pipe.

[0083] After the almost complete entry of the TTR (L) into the support pipe, the gap provided by the hourglass-shaped region (d) needs to be suppressed in this region called the Conical Surface for Gap Suppression (e), to align the support region of the TTR (L) with the support slips (3) of the upper cone (k) and promote the effective alignment between the TTR (L) and the Support Pipe.

[0084] The cylindrical surface for transmitting the shear force (f) is the last element of the TTR (L) to come into contact with the Support Pipe, thus ending the pull-in operation. As the spherical geometry (c) and the cylindrical surface (f) present a tight tolerance in relation to the internal diameter of the Support Pipe, the combination of such manufacturing requirements establishes a high self-alignment capacity of the TTR (L). A great advantage of the tight tolerance of this cylindrical surface is the elimination of the need of including a movable component for suppressing the gap and for transmitting the shear force coming from the riser.

[0085] The coupling method (pull-in) starts with the entry of the TTR (L) in the Support Pipe, where it is pre-aligned. The contact of the spherical geometry (c) of the TTR (L) then begins, creating the first resistant torque to the entry of the TTR (L) in the Support Pipe. From there, it can be noted that the conical surface of the TTR (L) is in contact with the Support Pipe, in order to eliminate the gap between the two of them and the consequent alignment and centralization of the TTR (L) inside the Support Pipe. With the TTR (L) already centered on the Support Pipe, it approaches the contact with the slips (3). The TTR (L) starts touching the slips (3), pushing them upwards together with the slip (3)/fork (2)/axle (1) assembly. After the end of the upward movement of the slip (3)/fork (2)/axle (1) assemblies, it descends due to the effect of gravity acceleration after losing contact with the TTR (L), and the slips (3) move down. After completing the downward movement, the TTR (L) is lowered and is completely supported by the slips (3).

[0086] Alternatively, the retraction mechanism (12) of the slips (3) can be used for the final pull-in step described in the previous paragraph. That is, the step of touching the TTR (L) on the slips (3) is replaced by a previous retraction of the slips (3) using the retraction mechanism (12). After the end of the upward movement of the TTR (L), the retraction tool (15) is activated in the opposite direction to extend the slips (3) and allow the final seating of the TTR (L).

[0087] For the uncoupling method (pull-out), it is necessary to install the automated slip retraction mechanism (3), whose main components are: slip retraction mechanism bars (12), axle extender (14) and slip retraction tool (15), as can be seen in FIGS. 6, 7 and 13. After installing the Automated Retraction Mechanism, it is necessary to raise the TTR (L) so that it is no longer resting on the slips (3), over-pull position, FIG. 12. The next step is for the retraction tool (15) of the slips (3) to act on the axle extender (14) so that the axle (1)/slip (3)/fork (2) assembly, on which the extender (14) is attached, starts to be retracted. With this movement, all retraction bars (12) of the slips begin to move due to kinematic restrictions, thus retracting the other slip (3)/fork (2)/axle (1) assemblies. Next, the TTR (L) can be lowered and removed from the upper cone (k), FIG. 13.

[0088] It should be noted that, although the present invention has been described in relation to the attached drawings, it may undergo modifications and adaptations by technicians skilled on the subject, depending on the specific situation, but provided that it is within the inventive scope defined herein.