WO2011000039A1

WO2011000039A1 - Facilitating subsea intervention

Info

Publication number: WO2011000039A1
Application number: PCT/AU2010/000822
Authority: WO
Inventors: Robert William Jones; Alexander Jeffrey Burns
Original assignee: Well Ops Sea Pty Ltd
Priority date: 2009-06-30
Filing date: 2010-06-30
Publication date: 2011-01-06

Abstract

A system and method facilitating deployment or retrieval of equipment between a vessel or platform and a subsea installation comprises: At least one guideline between the subsea installation and the vessel or platform, at least one guide (40) connected to the guideline, wherein each guide may comprise of a framework, with multiple arms (41-44) extending from a central portion, such as a guiding ring (45), each arm arranged to permanently or releasably connect directly or indirectly to the guideline, and a flexible support member (38) supporting equipment (4) being deployed or retrieved through the at least one guide, the at least one guide limiting transverse movement of the flexible support member. The guide(s) can support one or more service connections (32, 33) between the vessel/platform and the subsea installation. At least one of the guides includes a bottom-line guide.

Description

FACILITATING SUBSEA INTERVENTION

TECHNICAL FIELD

The present invention relates to subsea intervention, such as riserless or rigless subsea well intervention.

BACKGROUND

Subsea intervention typically utilises connections between a platform or vessel on or above the surface of the water and a subsea installation, such as a wellhead, positioned near or on the seabed. In the case of a wellhead, the wellhead might have a Christmas tree.

Intervention can be for the purposes of monitoring the installation, such as decommissioning, sealing, maintenance or inspection of a well.

In the case of a well, intervention can require the insertion of equipment into the subsea wellhead to carry out one or more of these or other tasks. To achieve this, a tool is lowered from the platform or vessel into the wellhead.

However, problems have been identified that deepwater and/or strong currents can cause the tool to drift away from the wellhead.

To avoid this, the weight of the tool could be increased, but this would require a respective increase in the thickness of the spoolable flexible supporting member, such as a cable, to support the heavier tool. This adds cost to the system and structure to support it. If the thickness of the flexible supporting member is not increased, the supporting member is likely to break.

Deepwater causes problems because the currents within the water above the tool can cause the long length of the flexible supporting member to drift, which in turn can cause the tool itself to drift away from the wellhead in the prevailing currents.

As the tool descends into deeper water, the mass of the tool proportional to the mass of the flexible supporting member becomes less significant. This means the tool mass becomes less dominant in the system and less able to overcome the current drag on the supporting member.

Even in shallower depths, if the currents are strong the tool and/or the flexible supporting member can drift. Such drifting can cause the tool and/or flexible supporting member to become entangled with other connections between the platform/vessel and installation. Drifting can cause the tool or equipment being lowered to miss the subsea installation.

Currents can cause the depth control problems for the tool/equipment being lowered on the flexible supporting member. Lateral displacement of the flexible supporting member causes the tool/equipment at the end of the member to vary in depth in the water. With the current acting on the flexible supporting member, the longer the member the greater the variation in vertical position and lateral position of the tool/equipment. A flexible supporting member of several hundreds of metres in length can be subjected to several tens of metres of variation in vertical position of the tool/equipment.

Drift can cause offset thereby causing problems in positioning the tool/equipment at the subsea installation, and particularly when trying to put a tool down a wellhead. Drift can similarly cause issues with or inability to deploy the tool down the wellhead even once located in position.

Attempts to address some of these problems have been tried. International patent applications published as WO 00/43632 and WO 2008/155046 each disclose a system for accessing oil wells with a compliant guide and coiled tubing. WO 00/43632 discloses a system using a compliant guide to act as a conduit to pass coiled tubing to the subsea wellhead and for the movement therein of a 'conveyence'. The spoolable compliant guide consists of a hollow tube. The system discusses the avoidance of need for heave compensators.

WO 2008/155046 in particular discloses a system for monitoring and evaluating parameters related to the use of a spoolable compliant guide system in subsea well intervention operations. However, as explained in WO 2008/155046, such spoolable compliant guides suffer from a variety of stresses and wearing agents that can lead to material fatigue. As stated, such stresses can affect the integrity of the compliant guide. Another problem highlighted in WO 2008/155046 is that the shape of the compliant guide itself can affect conveyance (tool or equipment) capabilities and other operational parameters. WO 2008/155046 therefore proposes a complex arrangement of electronic sensors deployed at intervals along the length of the compliant guide to monitor the system and help to address the problems associated with the system in WO 00/43632. This adds considerable cost and complexity to the overall system and does not alleviate the wear problems rather it monitors the conditions in order to detect wear problems.

With this in mind, it would be desirable to improve deployment or retrieval of a tool to a subsea installation by alleviating problems associated with drift without making the system overly complex.

SUMMARY OF THE INVENTION

An aspect of the present invention provides a method to facilitate deployment or retrieval of equipment between a vessel or platform and a subsea installation, the method including;

providing at least one guideline between the subsea installation and the vessel or platform;

providing at least one guide member connected to the guideline; and passing a flexible support member supporting equipment being deployed or retrieved through the at least one guide, the at least one guide limiting transverse movement of the flexible support member.

Multiple guidelines may be provided. The guide(s) may be releasably attachable or permanently attached to the guideline(s). In the case of releasably attachable guides, the guide/guides may be attached to the one or more guidelines during deployment of the guideline(s).

During deployment and/or retrieval, the equipment may be guided through the guide(s) by a remotely operated vehicle (ROV), manned submersible and/or one or more divers.

Multiple guides may be provided at spaced intervals along the guideline(s). The spacing may be regular, irregular or a combination of both.

The guideline(s) may be utilised to support one or more service connections between the vessel/platform and the subsea installation, such as one or more control fluid umbilical connections, electrical power, communications and/or electrical control umbilical connections.

An arrangement to compensate for heave or transverse motions of the vessel or platform may be included, such as one or more counterweights attached the guideline(s) to allow further guideline to be deployed or retrieved with movement of the vessel or platform. Alternate methods of compensating for vessel movement, such as constant tension winches or in-line heave compensating cylinders (hydraulic or pneumatic) may also be used. This allows the system to cater for any change in effective depth of the water or in the position of the vessel or platform, such as due to waves or drift.

The guide(s) may be rigid or semi rigid means, such as a framework or plate, which may be a single piece of formed from multiple components. A flexible arrangement made from rope slings may also be used. For example, each guide may include multiple portions each extending to connect to a guideline. The guide may be in the form of a skeleton or framework having multiple arms extending from a central portion, each arm arranged to permanently or releasably connect to a guideline, either directly or indirectly.

A further aspect of the present invention provides a system to facilitate deployment or retrieval of equipment between a vessel or platform and a subsea installation, including;

at least one guideline between the subsea installation and the vessel or platform;

at least one guide member connected to the guideline; and

a flexible support member supporting equipment being deployed or retrieved through the at least one guide, the at least one guide limiting transverse movement of the flexible support member.

The system may include multiple guidelines.

The system may include one or more releasably attachable connectors to connect the guideline(s) to the installation.

Releasable attachments to attach one or more of the guides to one or more guidelines may be provided.

The system envisages one or more guides at spaced intervals along the guideline(s).

The guideline(s) and/or guide(s) may support one or more service connections between the vessel/platform and the subsea installation. The service connections are one or more control fluid umbilical connections, electrical power, communications and/or electrical control umbilical connections. An arrangement to compensate for heave, pitch, yaw, roll or drift of the vessel or platform may be provided. This may include one or more counterweights are attached the guideline(s) at the vessel or platform to allow further guideline to be deployed or retrieved with movement of the vessel or platform. The compensation arrangement may be passive or active (powered).

The guide(s) may include rigid or semi rigid portions, such as a framework or plate, and optionally as a single piece or formed from multiple components.

The guide(s) may include flexible or resilient members, such as rope or cable arms, to connect to the guideline(s).

Connection to the guideline(s) may be by one or more releasable clamps or connectors, or may include one or more permanent connections.

Each guide may include multiple portions extending to each connect to a guideline. For example, each guide may a skeleton or framework, such as having multiple arms extending from a central portion, each arm arranged to permanently or releasably connect directly or indirectly to a guideline.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows problems associated with known subsea deployment systems.

Figure 2 shows a system according to an embodiment of the present invention with multiple guides spaced at intervals along guidelines between a vessel and a subsea installation.

Figure 3 shows additional problems associated with connecting service and control lines between a vessel and a subsea installation

Figure 4 shows an embodiment of the present invention with the provision of service and control lines connected between the vessel and the subsea installation.

Figures 5 and 6 show particular embodiments of the present invention.

Fig 7 shows details of a guide frame or 'spider' including means for handling of the mainline, guidelines and podlines according to an embodiment of the present invention.

Fig 8 shows the mainline guide detail of figure 7 at an enlarged scale.

Fig 9 shows the guideline guide of figure 7 at an enlarged scale. Fig 10 shows the podline clamp used in the embodiment shown in figure 7 at an enlarged scale.

Fig 1 1 shows a bottomline and corresponding guide according to an embodiment of the present invention.

Fig 12 shows a bottomline with corresponding sheave pulley and guide according to an embodiment of the present invention

DESCRIPTION OF PREFERRED EMBODIMENTS

Nomenclature

Guideline or Guidewire - cable proving guidance only.

Mainline or Wireline - cable used to lift tools and other parts such as a SID.

Podline - cable providing no guidance or lifting capability but to tether service hoses, data cables etc.

Spider - a particular cross-formed guide. Examples shown in the accompanying figures.

Subsea Intervention Device (SID) - device attached to the

Christmas tree and used to control the flow of oil/gas whilst intervention work is done. Intervention tools are lowered through the SID.

In Figure 1 , a vessel 1 is positioned over a subsea installation 2. A line 3 is lowered from the vessel. The line has a tool 4 at the distal end thereof. The tool can weigh approximately 50kg to 500kg or more. The line 3 may provide only a physical support for the tool or may also provide electrical signal connectivity between the tool and the vessel for sending and/or receiving instructions and data. Tension T is set up in the line as a result of the weight of the tool and also due to side currents C against the line. If the current is sufficiently strong, which can occur due to large currents and/or at increased water depths WD, the line 3 can be caused to drift. If this occurs when lowering the tool, it can be very difficult to position the tool at or close to the installation. Furthermore, if the tension is sufficiently high in the line, the line may break and the tool may be lost or difficult to retrieve. Water depths of between 300m and 2000m, and up to around 3000m are envisaged to be the operable depths where these problems occur.

In Figure 2, multiple guidelines 10, 1 1 connect the vessel to the subsea installation. One or more of these can be connected by permanent or releasable connections to the installation. Guidelines can be deployed from the vessel or platform from a reel or spool (not shown). The guidelines 10,1 1 support therebetween guides 12 spaced at intervals along the length of the guidelines. Each guide acts to guide. Spacing GS between adjacent guides can be selected to suit the prevailing conditions, including current C speed, current direction, wind speed and direction that might cause the vessel to drift, and water depth WD.

Each guide has the wireline 3 passing through it. Drift of the wireline is restricted by the guides. During deployment of the system, each guide may be attached to the guidelines as the guidelines are deployed, or may be pre-attached before deployment. Attachment may be permanent or releasable. Releasable attachment is preferred for adaptability of the system to suit prevailing conditions and for maintenance purposes. However it may be more cost and/or time efficient to have the system preassembled before deployment.

In Figure 3, there is shown service equipment supply 20 deployed to the seabed. Service connections are made between the supply 20 and the installation 2 via one or more umbilical connections 22. These can supply electrical power, electrical control and/or data, pressurised gas, hydraulic feed, etc. One or more connections are provided between the vessel and the supply 20. As is shown, during deployment of the supply 20, the connecting line(s) may drift due to the same forces that would affect the line 3 connecting the vessel with the installation. Consequently, this line or lines are prone to breakage or entanglement either with itself or with other lines or structures or even an ROV. Tension in the line(s) due to the current can exceed the strength of these line(s) (such as umbilical lines) resulting in breakage. Also, these umbilical lines can become entangled with the wireline where one drifts into the other.

Drift can also cause problems when trying to land the supply 20 (clump) next to or near to the installation, especially when the installation is a complex and/or large and/or delicate structure. Figure 4 shows an alternative embodiment of the present invention. Guidelines 30 are deployed from the vessel 1 and are connected between the vessel and the installation 2. The guidelines (wirelines) support guides 31 at spaced intervals. Service lines 32 are deployed connected to one or more of the guidelines. These service lines may be umbilical connections to supply power, control or data 33 to or from the installation or tool, and may provide a supply of lubricant or pressurised fluid, such as hydraulic fluid or compressed gas for operational purposes 32. For example, these may include a control fluid umbilical, lubrication (grease) umbilical or control signal (electrical or optical) or power umbilical. A support line 3 for the tool 4 is deployed through each of the guides 31 . The guides restrict drift of the line. The line 3 may provide support for the tool in order to deploy and retrieve the tool, but may also provide electrical power, control or data between the vessel and tool. The installation can be a subsea wellhead, which may include a Christmas tree, and may include structure or equipment connected to the wellhead that has been previously deployed.

Figures 5 and 6 show particular embodiments of the present invention. In figure 5, service umbilical lines 32,33 are deployed from reels 34,35. Heave, pitch, roll, yaw or drift of the vessel 1 (or other platform) are compensated for by a compensation system, which includes counterweights 36a-36d. Each weight is connected to a respective guideline. In at least one embodiment there are four guidelines, though more or less may be provided. The support line 38 for the tool 4 is deployed from a further reel 37. This also has its own compensation means. Each guideline is connected at a distal end thereof to the installation. In this arrangement, a square pattern is created with a guideline at each corner. Umbilical lines are run down diagonally opposing corners to evenly distribute their load forces. Guide frames 40 are spaced at intervals along the length of the guidelines. These include four opposed arms in the form of a cross. However, other arrangements are envisaged, such as twin armed, triple armed and other multiple arm arrangements, as well as plate and plate, panel or mesh arrangements. The guides are connected to the guidelines. In the embodiment shown, a pair of opposed arms are connected to diagonally opposite guidelines 41 ,42. The other arms 43,44 may be connected to their respective guidelines or may be free running i.e. the guideline may merely pass through an aperture in each respective arm. The guide 40 includes a central hub 45 for the arms. The hub includes an aperture 46 through which the wireline 3 passes. The hub, supported by the guide arms and retained in place by connection of at least some of the arms to the guidelines, restricts drift of the wireline and the tool.

Figure 6 shows a lubrication tool 4 which can be used to provide a dynamic seal, such as a grease seal, at a point on the wireline 3,38. This seal might be where the wireline passes into the installation 47. The seal can prevent fluid ingress from affecting electrical signals and connection. The dynamic seal allows for movement where a fixed seal, such as o-rings etc, would distort and cause leakage. The lubrication tool can be deployed or retrieved using a separate line to the wireline (which separate line can also be used to retrieve the tool if the wireline should break). The aperture 46 on each guide can be sufficiently large so as to allow passage of the lubrication tool. Podlines or service lines 48a,48b are attached to respective guidelines 36.1 , 36.2. The guideframe or spider is attached to the guidelines 36.1 , 36.2 via respective clamps 49a,49b.

Figure 7 shows an embodiment of an alternative arrangement for mounting the guide frame 40 to two of the guidelines 36.1 ,36.2 and for providing relative sliding guides 50a,50b allowing the guide frame to be guided and steadied by the two fixed guidewires 36.3,36.4 whilst the guideframe is lowered into position whilst attached to the other two guidewires 36.1 ,36.2. Two of the opposed arms 41 ,42 of the guide frame are fastened to their respective guidewire 36.1 ,36.2. In the embodiment shown, fastening is achieved by respective clamps 52a,52b utilising bolt fastened clamps. However, it will be appreciated that other fastening means can be employed within the spirit and scope of the present invention. For example, sheaving, wedges, convoluted or labyrinth path fasteners. The sliding guides 50a,50b can be opened to allow the respective guideline 36.3,36.4 to pass therethrough and then closed up and fastened using fastening means 53a,53b. Likewise, the central aperture 45 can be provided with an opening means 45a to allow the wireline 3,38 to pass through the aperture or be removed from the aperture. Alternative arrangements are considered to fall within the scope of the present invention, such as a spiral path ring. Figure 8 shows a partial view of an embodiment of a retainer device to facilitate retaining the wireline within the central guide aperture 45 or releasing it therefrom. In this embodiment, the central guide is not solid all the way around, rather, has an opening 45a with the opposed ends of the guide incorporating a pair of facing flanges or plates 55a,55b defining a slot therebetween. The wireline (not shown) can be passed through the slot of the opening and into the aperture of the guide. A filler 56, in this embodiment in the form of a plate 57 is then inserted into the slot and retained in place by a fastener 58 in the form of a bolt 58a and nut 58b passing through both of the flanges/plates 55a,55b and the keeper 56 therebetween. This arrangement prevents the wireline from coming transversely/laterally out of the guide 45 until the retainer is released. A locating device, such as a pin arrangement 58 on the keeper and corresponding recesses 59 on the flanges helps to locate the keeper in place and prevent the keeper falling out when the fastener is removed. The keeper can then be freely lifted out of position when required.

Figure 9 shows an embodiment of a guideline retainer of a guideline guide 50a,50b at a distal end of one of the arms 43,44 of the guide frame. It will be appreciated that one or more of the other arms (not shown) may have a corresponding guideline guide depending on the configuration used. Similar to the central guide, this guideline guide includes a slot 60 between two facing flanges or plates 61 a,61 b. The slot allows the guideline to be inserted or removed from the guideline guide. The slot is closed off by a keeper plate 62 in a similar fashion to the retainer of the central guide. This keeper has a support pin arrangement 63 and corresponding recesses 64 on the flanges of the guide 50. a fastener 65 retains the keeper in place.

Figure 10 reveals a fastener 52a,52b,70 for removably attaching the guide frame arm 41 ,42 to a guideline 36.1 ,36.2 per figure 7. The fastener includes a fixed portion 71 and a movable portion 72. In this embodiment the movable portion is pivoted via a pivot 73 to the fixed portion. Alternative arrangements are envisaged, such as removable fasteners, such as bolts or pins, or interlocking projection and slot arrangement. With the guideline placed between the two portions, the fastener is closed and tightened such that the guideline is clamped therebetween and the guide frame arm is attached in place. A releasable fastener 74 arrangement, such as a bolt and nut can be used to close and tighten the fastener 52a,52b,70.

Figure 1 1 shows another embodiment of a guideframe 80. This embodiment includes a bottom guide 81 on the frame/spider 80 through which passes a bottomline 82. Additionally, on a lowermost spider (not shown) there is also releasably or permanently attached to it underneath a sheave pulley (not shown). The bottomline 82 can pass through the sheave pulley (for example as shown at the dotted portion of the bottomline 82 in figure 1 1 ). The bottomline 82 can be attached to a tool at the surface and used to guide the tool down through the guides without the need to use an ROV. The bottom guide 81 guides the bottomline 82 and prevents that line becoming entangled with the tool and the other lines at the bottom. Other guide frames may include a bottom guide.

In figure 12, the bottomline 82 passes through the bottom guide 81 and around a bottom pulley 83. The bottom pulley in this embodiment is attached to the lowermost guide frame, assists the tool to travel centrally through the aperture 46 of the guide 45. This helps to prevent the wireline and tool otherwise getting stuck during travel in either an upwards or downwards direction. The guide 81 is attached to an additional guide arm 81 a which also supports a bracket 83a for the pulley wheel 83b.

Deployment Example (embodiment using 4-guidewires, SID, Podlines)

Lower first guideline and, using a remotely operated vehicle (ROV), latch the guideline onto the Christmas tree.

Lower second guideline and, using the ROV, latch that onto Christmas tree.

If tangling of guidelines occurs or is likely, the ROV takes this second guideline down from the surface to the Christmas tree.

On the vessel, attach two podlines and mainline to the SID.

Lower this assembly though the moon pool of the vessel using the mainline to support the assembly. Three winches might be used, one for each cable, and each independently controlled to balance the run out of the cables one-to-another.

At spaced intervals of cable lowering, such as approximately every 10m, the winches are stopped and a standard podline clamp is attached to secure each of the umbilicals to their respective podline. When attached the winches are restarted and another length of cable (e.g. 10m of cable) is run out.

At a required point, say the point of the first 200m, and at spaced intervals thereafter, say every 200m thereafter, of the cables being lowered into the water, the winches are stopped and a guide frame or spider is typically attached to the podline cables by, for example:

sliding the mainline through the central slot in the spider and closing the gap with a filler piece and bolts;

sliding the guidelines through the guidelines slots in the spider and replacing the filler piece and bolts; and

Locating the podlines on the opened spider podline clamps and closing and locking the clamps to grip the spider to the podlines.

The term 'spider' is used to describe the multi arm/leg guide frame. Restarting the winches.

The above procedure is continued until the SID assembly is above the

Christmas tree.

The SID is then:

1. guided onto the Christmas tree;

2. the tension on the main line released;

3. the SID is connected to the Christmas tree; and

4. the mainline released and brought back to the surface. The first selected tool is attached to the mainline and lowered through the water.

During the ROVs decent the ROV is available to guide the tool through the central ring of each spider (see following alternative embodiment).

The tool is finally guided into the SID by the ROV.

After using the tool the mainline is operated and the tool winched on deck, usually without the assistance of any ROV.

On deck, the first tool is removed and a tool second tool is attached to the mainline. This tool is lowered through the water and it approaches a spider, the ROV guides the tool through the central ring of the spider. It may be necessary to stop and restart the mainline winch to enable this to be accomplished.

In practice, the ROV can only descend very slowly, relative to the speed of the winch lowering a tool and thus the deployment of a second or subsequent tool is dependent entirely on the descent speed of the ROV. Additionally each time the ROV is required to guide the tool through the central ring of the spider, there is always the possibility that the ROV itself will become entangled in the guidelines and/or podlines.

Another embodiment includes a further guiding feature on the spider though which passes a bottomline. Additionally, on the lowermost spider there is also attached to it underneath a sheave pulley which is used as follows:

Either at Step 3, additionally attach the bottomline to the SID, or alternatively, at Step 6 additionally attach the bottomline to the first spider to be deployed (lowermost spider) after first passing the bottomline over a sheave pulley.

After the tool as been used, and prior to Step 12, the tool is winched upwards through the lowermost pulley, and the bottom line attached to the bottom of the tool.

The tool, with the bottomline attached, is winched onto the deck.

An alternative tool can be attached to the mainline and the bottomline.

Depending on circumstances, the tool can be either lowered or pulled downwards and, due to the attached bottomline, the tool as it descends can be guided through the central spider hole - thus dispensing with the need to use an ROV.

A further benefit of the using a bottom line is that when buoyancy effects on the tool are present, the tool can be pulled positively downwards by the bottomline which is attached to it, rather than relying entirely on the weight of the tool to enable descent of the tool through the water.

Similar deployment techniques would be adapted for use with a single cable.

Many subsea oil/gas installations include several wellheads arranged close to one another which are quite often template drilled in a rectangular array. The oil/gas from each well is then piped to a central manifold. In such cases, it would be convenient to "bunny hop" from Christmas tree to Christmas tree without the necessity of pulling all the guidelines, podlines and any SID to the surface and then having to redeploy them. One or more embodiments of the present invention enables this to done: Unlocking the SID from the first Christmas tree.

Attaching the mainline to the SID.

Lifting the SID upwards to a safe height above the well installations.

Detaching one guideline from the first Christmas tree and attaching it to the second Christmas tree.

Detaching the second guideline from the first Christmas tree and attaching it to the second Christmas tree.

Repositioning the vessel and tensioning the guidelines.

Lowering the SID and reconnecting it as described earlier.

Repeating this procedure as often as required.

In the above procedure the podlines are not disconnected from the SID - which gives efficiency and time saving benefits.

In addition, at the end of the intervention work the equipment can be retrieved on board the vessel by reversing each of the steps of the deployment.

Claims

CLAIMS:

1. A method facilitating deployment or retrieval of equipment between a vessel or platform and a subsea installation, the method including;

2. A method according to claim 1 including utilising multiple guidelines.

3. A method according to any one of the preceding claims, including releasably attaching the guideline(s) to the installation.

4. A method according to any one of the preceding claims, including releasably attaching one or more of the guides to one or more guidelines.

5. A method according to claim 4, wherein releasable attachment is effected during deployment of the guideline(s).

6. A method according to any one of the preceding claims, wherein during deployment and/or retrieval, the equipment may be guided through the guide(s) by a remotely operated vehicle (ROV), manned submersible and/or one or more divers.

7. A method according to any one of the preceding claims, wherein multiple guides are provided at spaced intervals along the guideline(s).

8. A method according to any one of the preceding claims, wherein the guideline(s) and/or guide(s) support one or more service connections between the vessel/platform and the subsea installation.

9. A method according to any one of the preceding claims, wherein the service connections are one or more control fluid umbilical connections, electrical power, communications and/or electrical control umbilical connections.

10. A method according to any one of the preceding claims, including an arrangement to compensate for heave, pitch, yaw, roll or drift of the vessel or platform.

1 1 . A method according to claim 10, wherein one or more counterweights are attached the guideline(s) at the vessel or platform to allow further guideline to be deployed or retrieved with movement of the vessel or platform.

12. A method according to any one of the preceding claims wherein the guide(s) are rigid or semi rigid means, such as a framework or plate, and optionally single piece or formed from multiple components.

13. A method according to claim 12, wherein each guide includes multiple portions extending to each connect to a guideline.

14. A method according to claim 12 or 13, wherein the guide is a skeleton or framework having multiple arms extending from a central portion, each arm arranged to permanently or releasably connect directly or indirectly to a guideline.

15. A system to facilitate deployment or retrieval of equipment between a vessel or platform and a subsea installation, including;

at least one guide member connected to the guideline; and

16. A system according to claim 15 including multiple guidelines.

17. A system according to any one of claims 15 to 16, including one or more releasably attachable connectors to connect the guideline(s) to the installation.

18. A system according to any one of claims 15 to 17, including releasable attachments to attach one or more of the guides to one or more guidelines.

19. A system according to any one of claims 15 to 18, wherein multiple guides at spaced intervals along the guideline(s).

20. A system according to any one of claims 15 to 19, wherein the guideline(s) and/or guide(s) support one or more service connections between the vessel/platform and the subsea installation.

21 . A system according to any one of claims 15 to 20, wherein the service connections are one or more control fluid umbilical connections, electrical power, communications and/or electrical control umbilical connections.

22. A system according to any one of claims 15 to 21 , including an arrangement to compensate for heave, pitch, yaw, roll or drift of the vessel or platform.

23. A system according to claim 22, wherein one or more counterweights are attached the guideline(s) at the vessel or platform to allow further guideline to be deployed or retrieved with movement of the vessel or platform.

24. A system according to any one of claims 15 to 23, wherein the guide(s) are rigid or semi rigid, such as a framework or plate, and optionally single piece or formed from multiple components.

25. A system according to claim 24, wherein each guide includes multiple portions extending to each connect to a guideline.

26. A system according to claim 24 or 25, wherein the guide is a skeleton or framework having multiple arms extending from a central portion, each arm arranged to permanently or releasably connect directly or indirectly to a guideline.

27. A system according to any one of claims 24 to 26, wherein at least one of the guides includes a bottom line guide.