GB2335723A

GB2335723A - Pipeline connection apparatus

Info

Publication number: GB2335723A
Application number: GB9806521A
Authority: GB
Inventors: Jacob De Baan
Original assignee: Bluewater Terminal Systems NV
Current assignee: Bluewater Terminal Systems NV
Priority date: 1998-03-26
Filing date: 1998-03-26
Publication date: 1999-09-29
Anticipated expiration: 2018-03-26
Also published as: GB9806521D0; GB2335723B

Abstract

The apparatus attaches an end of the pipeline (6), e.g. a rigid sub-sea pipeline, to a floating body (1), such as a tanker or loading buoy. The pipeline (6) is suspended from the floating body (1) by a suspending member (7) pivotally attached at one end to the floating body (1) and at the other end to the pipeline (6). A flexible fluid conduit (9) provides a fluid path between the pipeline (6) and the floating body (1). The suspending member (7), e.g. a chain, metal or synthetic fibre wire, accommodates relative movement between the end of the pipeline (6) and the floating body (1).

Description

2335723 PIPELINE CONNECTION APPARATUS In offshore oil production it is

necessary to connect floating vessels with subsea equipment by means of pipelines. These floating vessels may be tanker loading buoys or floating production vessels, such as tankers, semi-submersibles, SPAR buoys etc.

In many instances flexible flowlines are employed although in some cases, especially in deep water, rigid steel flowlines, may be used to advantage.

A major problem in the use of rigid flowlines is the physical interface between the flowline and the floating vessel, particularly if the dynamic behaviour of the vessel due to its response to wind and wave motions is considerable. Large angular relative motion between the floating vessel and the rigid pipeline riser make the design of the joining element difficult or may even preclude it.

To date. the so called elastomeric ball joint is the only system that has proven capability. However, it has limitations in terms of the maximum relative angle and tension that it can accept, as well as limits on the speed of angular variation, particularly where the flowline diameter is large, e.g., 40 cm (16 inches) or more.

Accordingly, the present invention provides apparatus for attaching the end of a sub-sea pipeline to a floating body, comprising at least one suspending member having a first end attachable to the floating body in an articulated manner and a second end attachable to a pipeline so as to suspend the pipeline from the floating body, and a flexible fluid conduit having an first end attachable to the body and a second end attachable to the pipeline so as to provide a fluid path between the fluid body and the pipeline.

Preferably, the suspending member is a flexible component which may be in the form of a chain, a metal wire or a man made fibre wire.

In another aspect, the invention comprises a floating body incorporating one or more units of the attachment apparatus described above in order to attach to the body one or more subsea pipelines.

The floating body may consist of a floating bouy or a vessel such as a tanker.

The invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which; Fig.1 shows a first embodiment of the present invention for attaching a pipeline to a floating buoy; Fig.2 is a schematic drawing illustrating how the embodiment of Fig. 1 may be utilised; and Fig. 3 is a schematic drawing illustrating an alternative utilisation of the embodiment of Fig. 1.

With reference to Fig.1, this shows a floating vessel which in this instance is a typical tanker loading buoy 1. The loading buoy 1 is anchored to the seabed by conventional anchorlegs 2. A turntable 3 is rotatably mounted on buoy 1 and allows for the mooring - 3 of a vessel 4 such as a tanker in a known manner. A fluid transfer system 5 allows the vessel 4 to receive fluids via the buoy 1 from a subsea pipeline 6.

The end of the subsea pipeline 6, which is typically in the form of a substantially rigid steel pipe, is suspended beneath the buoy 1 by means of a suspending member 7 which is placed in tension by the weight of the pipeline 6 The suspending member 7 is a flexible member such as a chain, steel wire or a man-made fibre wire. one end of the suspending member 7 is attached to the buoy 1 in a manner to allow pivoting relative to the buoy 1 to take up any movement of the buoy in response to wind or wave is motion. This attachment may be in the form of an articulated joint 8 of any convenient configuration or articulated chain stopper such as that used to connect the anchor leg 2 to the buoy 1 in a conventional manner.

More than one suspending member 7 may be used if necessary to support the end of one pipeline 6. In addition the attachment between the suspending member 7 and the pipeline may be articulated.

In order to provide a fluid path between the end of the pipeline 6 and the buoy 1, a flexible hose or pipe 9 is attached between the two, providing a fluid path for transmission of fluid from the subsea pipeline 6 to the buoy 1 and thence to the vessel 4. The flexible pipe 9 can be of any suitable type.

In this way, relative movement between the buoy and the end of the subsea pipeline 6 is accommodated by the suspending member 7, the articulated joint 8 and the flexible pipe 9.

Figure 2 shows in schematic form how the system of Figure 1 can be utilised in practice to onnect a floating buoy 1 to a steel subsea pipeline 6, the other end of which is attached to a second floating body 10 such as a tanker. Although it is not illustrated in detail, the pipeline 6 is attached to the second floating vessel 1) by an attachment arrangement of the same form as shown in Figure 1.

Figure 3 shows an alternative utilisation of the apparatus of Figure 1, for connecting the end of the subsea pipeline 6 to a buoy 1, with the other end of the pipeline 6 being connected to equipment located on the seabed.

Although not illustrated above, the apparatus can of course be used to connect more than one pipeline to a particular floating body.

It will be apparent to those skilled in the art that the present invention provides an improved apparatus for connecting a subsea pipeline to a floating body, which apparatus can accommodate a greater range of movement between the body and pipeline than in previous systems. It will also be appreciated that a number of modifications to the precise details described above can be made without departing from the scope of the claims.

Claims

1. Apparatus for attaching an end of a subsea pipeline to a floating body, comprising at least one suspending member having a first end attachable to the floating body in an articulated manner and a second end attachable to the pipeline so as to suspend the pipeline from the floating body, and a flexible fluid conduit having a first end attachable to the floating body and a second end attachable to the pipeline so as to provide a fluid path between the floating body and the pipeline.

2. Apparatus as claimed in claim 1, wherein the suspending member comprises a flexible member.

3. Apparatus as claimed in claim 2, wherein the suspending member comprises a chain, a metal wire or a synthetic fibre wire.

4. A floating body including one or more of the units of the apparatus of any preceding claim for attaching one or more pipelines to the body.

5. A floating body as claimed in claim 4, wherein the body comprises a floating buoy.

6. A floating body as claimed in claim 4, wherein the floating body comprises a vessel such as a tanker.

7. Apparatus for attaching an end of subsea pipeline to a floating body substantially as herein before described with reference to the accompanying drawings.