WO2008012134A1

WO2008012134A1 - Connection tool

Info

Publication number: WO2008012134A1
Application number: PCT/EP2007/055638
Authority: WO
Inventors: David John Butcher; Richard John Wood
Original assignee: Verderg Connectors Ltd
Priority date: 2006-07-27
Filing date: 2007-06-08
Publication date: 2008-01-31
Also published as: GB2442972B; GB2442972B8; GB0614879D0; GB2442972A

Abstract

A connection tool for connecting a pipeline to a subsea connection structure which includes a connection porch into which the pipeline is connected, locating posts being positioned on either side of the connection porch, the tool comprising: - a tool chassis (30); - a carrier mounted on the chassis and adapted to releasably carry the pipeline (38) to be connected to the manifold; - a pair of locating sleeves (40) positioned at the front of the chassis in an arrangement corresponding to that of the guide posts on the porch (44) so as to be slideable over the guide posts (42) to hold the chassis adjacent the porch, each sleeve being split in half axially to provide an inner half (46) positioned near the front of the chassis and an outer half (48) distant from the front of the chassis, wherein the halves of each sleeve are moveable between an open position in which they are separated by a predetermined distance, and a closed position in which they are positioned next to each other.

Description

CONNECTION TOOL

Technical field

[0001] This invention relates to tools, apparatus and methods for connecting pipelines to subsea manifolds and other connection structures such as those used in offshore oil and gas production fields. Other uses include connecting flowlines to riser bases, pipeline termination assemblies, Christmas trees, etc.

Background art

[0002] In many offshore oil fields, production wells are completed by a production tree installed on the sea bed. The output from several wells is typically collected together at a subsea production manifold and from there to the surface, for example via floating production facility.

[0003] Connection between the subsea trees and manifolds can be by means of flexible or rigid pipelines, depending on circumstances. These relatively short pipelines are known as 'jumpers'.

[0004] Originally, connection of pipelines was performed by divers, but with the increasing use of deepwater developments and a desire to reduce the use of divers, systems that can be installed using remotely operated vehicles (ROVs) are being developed. Examples of such systems are the DMaC and FTC systems of VerdErg which are described on the Internet web site www.verderg.com.

[0005] When connecting flexible jumpers, it is possible to connect one end then the other and there is relatively little hindrance caused by the jumper to the installation procedure. However, it is often desirable to use rigid jumpers. In such a case, connection procedures can be much more complicated.

[0006] In the FTC system, the trees, manifolds and other subsea connection structures (the term 'connection structure' will be used throughout this document for all such structures) include a connection porch into which the pipeline is connected with locating posts being positioned on either side of the pipeline connection. One connection structure of an installation, the first connection end, typically has a connection porch with one guide post taller than the other whereas the other connection structures to be connected to will typically have guide posts the same size. A frame is used to support the connection tools and the flowline and is manoeuvred so as to position one of the connection tools adjacent the connection structure with one of the sleeves engaged on the taller of the guide posts. The frame is then manoeuvred further so as to pivot the first connection tool about the taller guide post and position the remaining sleeves over the corresponding guide posts, and then lowered so as to engage the remaining sleeves on the corresponding guide posts. The connection tools can then be operated to perform the connection.

[0007] To assist in location of the sleeves on the guide posts, the sleeves are flared at their lower ends to provide enlarged openings (inverted funnels). This allows a degree of mismatch between the alignment of the porch and ends of the flowline to be accommodated. However, the flare cannot be very large as doing so effectively increases the length of the connector which may otherwise inhibit key features of the connection structure design.

[0008] It is an object of this invention to provide a connection tool that can accommodate this mismatch without increasing the size of the connection beyond that which can be accommodated by a typical manifold design. This invention is based around the use of split locating sleeves that can be opened for engagement and closed for connection.

Disclosure of the invention

[0009] A first aspect of the invention comprises a connection tool for connecting a pipeline to a subsea connection structure which includes a porch into which the flowline is connected, locating posts being positioned on either side of the connection porch, the tool comprising:

- a tool chassis;

- a carrier mounted on the chassis and adapted to releasably carry the pipeline to be connected to the connection structure;

- a pair of locating sleeves positioned at the front of the chassis in an arrangement corresponding to that of the guide posts on the connection porch so as to be slideable over the guide posts to hold the chassis adjacent the connection porch, each sleeve being split in half axially to provide an inner half positioned near the front of the chassis and an outer half distant from the front of the chassis, wherein the halves of each sleeve are moveable between an open position in which they are separated by a predetermined distance, and a closed position in which they are positioned next to each other.

[0010] By providing the sleeves in a split form, positioning the halves in the open position when the sleeves are being located over the guide posts allows a greater degree of freedom in the positioning required to for effective engagement. Closing the split sleeves then allows the engagement to be made secure and provide accurate positioning of features in the elements forming the connection.

[0011] Preferably, each inner sleeve half is fixed to the chassis and each outer sleeve half is moveable relative to its respective inner sleeve half.

[0012] A drive mechanism is typically mounted on the chassis and arranged to move the halves of the locating sleeves between the open and closed positions. It is preferred that a separate drive mechanism is provided for each sleeve. The drive mechanism can comprises a drive screw or a piston and cylinder.

[0013] One or more rollers can be provided inside the sleeve halves. These can be useful to prevent jamming of the sleeves on the guide posts and thereby causing problems when installing to tool on and disconnecting the tool from the guide posts.

[0014] The carrier is preferably moveable on the chassis between a first position in which, when the chassis is held adjacent the porch, the end of the flowline is away from the porch, and a second position in which the end of the flowline is in the porch.

[0015] The apparatus preferably comprises a sub-structure at the front of the chassis on which the sleeves are mounted. It is particularly preferred to provide load reaction lugs on the sub structure for engagement in corresponding sockets on the connection porch. These lugs provide reaction for the load on the chassis when connecting the pipeline to the connection structure. [0016] A second aspect of the invention comprises apparatus for installing a pipeline into subsea connection structures, comprising a pair of connection tools according to the first aspect of the invention and a frame from which the connection tools are suspended, the frame being configured to position the connection tools in a configuration such that they can both be installed on respective connection structures at the same time.

[0017] A third aspect of the invention comprises method of connecting a pipeline between first and second subsea connection structures using an apparatus according to the second aspect of the invention, wherein the first connection structure comprises a connection porch with one guide post taller than the other, the method comprising:

- connecting connection tools to each end of the pipeline by means of the respective carriers;

- manoeuvring the frame so as to position one of the connection tools adjacent to one of the connection structures with one of the sleeves engaged on the taller of the guide posts and the remaining sleeves above the level of the tops of the remaining guide posts;

- configuring the connection tool for the second connection structure with the sleeves in the open position;

- manoeuvring the frame so as to pivot the first connection tool about the taller guide post and position the remaining sleeves over the corresponding guide posts;

- lowering the frame so as to engage the remaining sleeves on the corresponding guide posts; and

- closing the sleeves on the connection tool located at the second connection structure.

[0018] By arranging the sleeve in two halves it is possible to position the connection tools with the sleeves in the open position so as to make it easier to engage the sleeves on the guide posts more easily and then close the sleeves to secure the connection tool in the connection porch.

Brief description of the drawings

[0019] Figure 1 shows a schematic diagram of a generalised subsea development to which this invention relates; Figure 2 shows a connection tool according to an embodiment of the invention;

Figures 3-5 show various views of one embodiment of locating sleeve for use on a connection tool as shown in Figure 2;

Figures 6 and 7 show a second embodiment of the locating sleeve for use in the invention:

Figure 8 shows a third embodiment of the locating sleeve for use in the invention;

Figure 9 shows the initial position for an operation for connecting an L- shaped jumper between a manifold and subsea tree;

Figures 10 and 11 show perspective and plan views of the setup of Figure

9 in its initial position;

Figure 12 and 13 show perspective and plan views of the setup of Figure

9 in its final position; and

Figures 14 and 15 show schematically the possible alignment of the pipeline and guide posts. Mode(s) for carrying out the invention [0020] Figure 1 shows a schematic diagram of a generalised subsea development to which this invention relates. A number of wells have been drilled and completed with subsea trees 10, 12 located on the sea bed 14.

The output from each is taken, via a pipeline (also known as a 'jumper')

15, 16 to a production manifold 18 and from there via a pipeline 20 to a floating production facility 22 (for example an anchored production vessel).

The jumpers 15 connecting the trees 10 to the manifold 18 are rigid, having an L shape, whereas the pipelines 16 connecting trees 12 to the manifold are flexible. [0021] This invention relates to a tool for connecting the ends of the pipelines to the manifolds and trees (or any other such connection structures). The connection tool is shown in Figure 2 and comprises a chassis 30 which can be carried by an ROV or other support system (not shown) for underwater positioning. The chassis includes a pair of elongate, parallel side members 32 having a sub-structure 33 mounted at the front end thereof on hinge pins 35. A carrier 34 is mounted on the side members 32 so as to be slideable along the side members 32 under the influent of piston and cylinder arrangements 36 connected to the sub-structure 33. The carrier 34 also includes a mechanism for releasably carrying the end of a pipeline 38 to be connected to the connection structure. A pair of locating sleeves 40 are mounted on the sub-structure 33, the lower ends of the sleeves 40 being flared to form inverted funnels. The sleeves 40 and their operation will be described in more detail below. The sub structure 33 also carries a pair of downward facing taper end spigots 41 for engagement in corresponding mating sockets 45 in the porch structure 44.

[0022] In use, the connection tool is manoeuvred with the carrier 34 having the pipeline connected thereto towards the rear of the chassis 30, until the sleeves 40 are positioned over guide posts 42 on either side of a connection porch 44 on the connection structure. The tool is then lowered until the sleeves 40 engage over the posts 42, and the spigots 41 engage in the mating sockets 45 and the end of the pipeline 38 is aligned with the porch 44. The piston and cylinder arrangements 36 are then operated to advance the carrier 34 on the chassis 30 until the end of the pipeline 38 can be connected in the porch 44, the spigots 41 in the sockets 45 providing reaction for the loads involved in making up the connection. Following connection, the carrier 34 is disconnected from the pipeline 38 and the tool lifted to disengage the sleeves 40 from the posts 42 and the tool removed for re-use elsewhere.

[0023] Figures 3-5 show various views of one embodiment of locating sleeve for use on a connection tool as shown in Figure 2 in accordance with the invention. In this embodiment, the sleeve 40 is divided axially to form inner and outer sleeve halves 46, 48. The inner sleeve half 46 is fixed to the end of the side member 32 and provides a mounting for a piston 50. The outer sleeve half 48 has a pair of lateral arms 52 which extend into corresponding channels 54 on the inner sleeve half 46 and are connected to a drive pin 56 on the piston 50 which projects through a slot 58 in the inner sleeve half 46. Upper and lower roller pairs 60, 62 are provided on inside of the respective sleeve halves 46, 48. [0024] In use, the sleeve can be moved between an open position (as shown in Figures 3 and 4) in which the piston 50 is advanced and the outer sleeve half 48 is separated from the inner sleeve half 46, and a closed position (as shown in Figure 5) in which the piston 50 is retracted and the sleeve halves 46, 48 are next to each other.

[0025] When the connection tool is being lowered over the guide posts 42, the sleeve halves 46, 48 can be placed in their open position so as to allow greater freedom in position while still allowing the posts 42 to engage in the sleeves. Once the posts are engaged, the piston 50 can be stroked to close the sleeve halves 46, 48 and hold the guide post 42 securely in the closed sleeve. The rollers 60, 62 help to avoid jamming of the closed sleeve on the guide post 42 and allow the sleeve to be slid up and down on the guide post 42 even when in the closed position.

[0026] Figures 6 and 7, and Figure 8 show second and third embodiments of the locating sleeve for use in the invention. In Figures 6 and 7, the drive mechanism for moving the sleeve halves 46, 48 comprises a piston/cylinder arrangement 64 mounted on the side of the inner sleeve half 46 connecting to a corresponding lateral extension 66 of the outer sleeve half 48. Locating pegs 68 extend from the outer sleeve half 48 into corresponding bores 70 on the inner sleeve half 46 to maintain the alignment of the outer sleeve half 48 as it is driven by the mechanism 64. Rollers 60, 62 are provided as before.

[0027] The embodiment of Figure 8 corresponds to that of Figures 6 and 7, except that in this case, the piston/cylinder arrangement 64 is replaced by a drive screw 72 which is located at one end of the side member 32 and can be driven by a screw take-off on an ROV being used to position the connection tool.

[0028] Various changes can be made to these mechanisms without departing from the scope of the invention. As has been described, piston/cylinder arrangement can be replaced by drive screws. These can be electrically and or hydraulically powered depending on the positioning system being used. [0029] One particular procedure in which this invention has particular advantages is in the connection of rigid pipelines between connection structures (manifolds and trees , for example). Figure 9 shows the initial position for such an operation for connecting an L-shaped jumper 80 between a manifold 82 and subsea tree 84. The jumper 80 is provided, ready configured in its L-shape with connection tools 86, 88 of the type described above at each end. The jumper 80 and the connection tools 86, 88 are suspended from a rigid frame 90 which is itself suspended from a vessel above (not shown).

[0030] Figures 10 and 11 show perspective and plan views of the setup of Figure 9 in its initial position. In this case, the porch on the manifold 82 has asymmetric guide posts similar to those shown in Figure 2. In the initial position, the frame 90 is lowered until one of the sleeves on the connection tool 86 engages the taller guide post on the manifold 82. The jumper and connection tool arrangement is then pivoted around this post until the remaining sleeves are lined up over the other guide posts on the manifold 82 and tree 84. This position is shown in perspective and plan in Figures 12 and 13. If not already open, the sleeve halves on the connection tool 88 over the tree 84 are moved to their open position. The frame 90 is then lowered further so that all of the sleeves engage over their respective guide posts and the sleeve halves are moved to their closed position to hold the connection tool securely to the tree while the connection is made.

[0031] Figures 14 and 15 show the limit positions a, b for the sleeves 40 to engage the guide posts 42 when in their open position. The open position of the sleeves gives a much greater margin for error when locating the connection tool on the guide posts than with a simple single piece sleeve. Since the flow line can be several tens of metres in length, one leg of the L potentially being up to 50m, it can be difficult to ensure exact accuracy of length of jumper and position in the ends for connection.

[0032] However, the ability to close the sleeves to the same size as a single piece sleeve means that it does not interfere with the porch design when making up the connection. Also, the jumper can be made to length and the joint made up in a degree of tension to provide good alignment and positioning. Because the sleeves do not need such accurate positioning when in the open position, it is not so critical that the jumper configuration is accurate. The closing of the sleeves can use the flexibility in the system to deflect the jumper to fit. Other changes within the scope of the invention will be apparent.

Claims

1. A connection tool for connecting a pipeline to a subsea connection structure which includes a connection porch into which the pipeline is connected, locating posts being positioned on either side of the connection porch, the tool comprising:

- a tool chassis;

- a pair of locating sleeves positioned at the front of the chassis in an arrangement corresponding to that of the guide posts on the porch so as to be slideable over the guide posts to hold the chassis adjacent the porch, each sleeve being split in half axially to provide an inner half positioned near the front of the chassis and an outer half distant from the front of the chassis, wherein the halves of each sleeve are moveable between an open position in which they are separated by a predetermined distance, and a closed position in which they are positioned next to each other.

2. A connection tool as claimed in claim 1 , wherein each inner sleeve half is fixed to the chassis and each outer sleeve half is moveable relative to its respective inner sleeve half.

3. A connection tool as claimed in claim 1 or 2, wherein a drive mechanism is mounted on the chassis and arranged to move the halves of the locating sleeves between the open and closed positions.

4. A connection tool as claimed in 3 wherein a separate drive mechanism is provided for each sleeve.

5. A connection tool as claimed in claims 3 or 4, wherein the drive mechanism comprises a drive screw or a piston and cylinder.

6. A connection tool as claimed in any preceding claim, wherein one or more rollers are provided inside the sleeve halves.

7. A connection tool as claimed in any preceding claim, wherein the carrier is moveable on the chassis between a first position in which, when the chassis is held adjacent the porch, the end of the pipeline is away from the porch, and a second position in which the end of the pipeline is in the porch.

8. A connection tool as claimed in any preceding claim, further comprising a substructure at the front of the chassis on which the sleeves are mounted.

9. A connection tool as claimed in claim 8, further comprising one or more load reaction lugs on the sub structure for engagement in corresponding sockets on the connection porch for providing reaction for the load on the chassis when connecting the pipeline to the connection structure.

10. Apparatus for installing a pipeline into subsea connection structures, comprising a pair of connection tools as claimed in any preceding claim, and a frame from which the connection tools are suspended, the frame being configured to position the connection tools in a configuration such that they can both be connected to respective manifolds at the same time.

11. A method of connecting a pipeline between first and second subsea connection structures using an apparatus as claimed in claim 10, wherein the first connection structure comprises a porch with one guide post taller than the other, the method comprising:

- manoeuvring the frame so as to position one of the connection tools adjacent the first connection structures with one of the sleeves engaged on the taller of the guide posts and the remaining sleeves above the level of the tops of the remaining guide posts;