GB2228056A - Method and tool for remote replacement of a pipe module - Google Patents

Abstract

A tool used for diverless replacement of a pipe module (2) forming part of a pipeline system (5, 6) disposed on a bottom plate (1) located on the seabed comprises a supporting plate (29) and a telescopic frame (Figure 3) connectible thereto. The tool is lowered down and placed over the pipe module (2) which is to be replaced by means of a tool carrier. A coupling (33) on the tool engages a gripping head (28) on the pipe module. With the aid of screwdrivers on the tool, clamp couplings (11), connecting the pipe module to pipe ends of the pipeline system leading to said pipe module, are disconnected. The telescopic frame comprises two end plates (52, 53) which, by means of telescopic arms located therebetween, are capable of changing their intermediate distances with the aid of screw jacks. The end plates have internal slots which surround the push lugs on the pipe ends. After the clamp couplings have been disconnected, the pipe ends can be pushed apart by means of the end plates, the pipe module thus being disengaged from the pipeline system and, after the supporting plate and the telescopic frame have been disconnected, is capable of being raised to the surface with the tool carrier and the supporting plate for replacement. When a new pipe module is to be installed, the procedure is reversed. <IMAGE>

Description

METHOD AND TOOL FOR REMOTE REPLACEMENT OF A PIPE MODULE The present invention relates to a tool and method for diverless replacement of a pipe module (e.g. a pipe module which forms part of a bottom-based installation for the extraction of gas and oil). The requirement for diverless replacement is due to the fact that some underwater equipment is located at such great ocean depths that it is not possible for divers to work at such depths.

Installations and equipment on the seabed may, of course, be designed in many different ways and consist of many different components. However, a certain pattern can be traced on most installations used in oil and gas extraction. Common to many is that they comprise a bottom plate, a so-called Xmas tree" and an extensive pipe installation with valves etc.. For positioning of production, auxiliary and operating equipment of various kinds, so-called guide posts are also available, towards which the production and various tool carriers, tools and the like can be controlled from a surface-based production installation (e.g. a platform or ship).

Designs of tool carrier are disclosed, inter alia, in our GB-A-2211226 and in GB-A- filed on 6th February 1990.

When locating a bottom-based installation, it is often desirable to design the installation so as to satisfy certain future needs and so as to comprise spare or replacement facilities even from the start, i.e. when the installation is assembled at the surface or manufactured at the factory.

With a carefully prepared planning of the installation, future replacement, maintenance and alteration work can be carried out in a rational way. As mentioned, this invention relates to a tool for such replacement or main tenance and also to the actual method for carrying out the replacement or maintenance. However, the mode of operation of the tool pre-supposes that certain measures are taken during the manufacture of the bottom-based installation and that certain devices are included in which replacement or maintenance of certain pipe modules can be expected to be needed. By pipe modules in this connection is meant any of a plurality of different components, inter alia, such as straight pipe sections, valves included in a pipeline system, and sensors (e.g. for pressure or flow).

What constitutes the invention in its broadest aspect is set out in the following claim 1.

A tool for use in the method of the invention desirably has such a general design that it may be used with different types of tool carriers and different lowering and connection devices. In addition, as mentioned, certain conditions regarding the pipe installation and the pipe modules must be fulfilled.

One important condition is that the pipe modules have certain given standard lengths. The connections of the pipe modules to the pipeline system should be in the form of a flange for clamp connection pieces, i.e. as an annular or cone-shaped flange or the like. Further, the pipe ends connected to the pipe module should be formed with a corresponding clamp connection piece. The pipe module which is to be replaceable should be provided with a gripping head of some kind and desirably coacts with two guiding plates on the bottom plate.

The pipelines, not the pipe modules, are fixed to a bottom plate by means of a number of attachment devices.

These are provided at a certain distance from the coupling between the pipe modules and the pipes connected thereto.

The attachment and the rest of the pipe system are, however, designed so that the pipes can be pushed somewhat in the lateral direction through the respective attachment device. on that part of the pipe which is located between the attachment devices and the pipe modules, stop lugs can be welded. These stop lugs will make contact with the attachment devices when maximum permissible displacement of the tubes has been attained. On that part of the pipes which is located between the stop lugs and the pipe modules, pushing lugs can also be welded which act as attachment for a device for pushing the pipes apart. In the joint between a pipe module and a corresponding pipe, i.e. between the clamp connection pieces, a sealing gasket of some kind would normally be provided.

The bolted joint which retains a pipe module and an adjacent pipe end normally consists of a conventional pipe clamp coupling. Such a coupling consists of two halves which, from the point of view of installation, will be referred to later on in the description as the upper and the lower half, respectively. The halves are conveniently connected together by diametrically placed screws. When the halves are to be joined together, the clamp connection pieces of the pipe module and the pipe end are drawn towards each other due to the inner arcuate or conically shaped cross section area of the clamp coupling halves.

In order for the tool to fulfil its function, it should be capable of being positioned at the correct location. This has to be done with the aid of some kind of tool carrier, suitably according to the above-mentioned GB patent specifications. in that connection also guide posts positioned on the bottom plate can be used. The tool carrier can be provided in a suitable way with control devices for the positioning and lifting devices for the actual tool. Control signals, hydraulics, etc., can also be transferred, by way of the tool carrier, from surfacebased plant to the tool for its functioning. Two guiding supports below the pipe module can assist in the position ing.

A preferred tool for use in the method of the invention comprises two detachable parts, in the following called supporting plate and telescopic frame, respectively, which are both equipped for a variety of different functions.

The supporting plate is provided with fixing devices for connection with the tool carrier in question. It further comprises a hydraulic, lockable coupling fitting the gripping head of the pipe module. Hydraulic couplings are also provided to be able to connect and disconnect the telescopic frame to and from the supporting plate. The supporting plate is also provided with hydraulically driven screwdrivers for the screws of the clamp coupling and with a hydraulic motor for driving two reversible self-braking screw jacks mounted on the telescopic frame. Hydraulic coupling devices may be mounted on the supporting plate to be able to hold the upper clamp coupling halves when these are unscrewed from the lower clamp coupling halves.

The telescopic frame comprises two parallel telescopic arms, which both consist of a supporting beam on which are mounted grippers for engaging the supporting plate. Inside and mounted in each supporting beam are two identical telescopic beams extending outwardly from the supporting beams.

The telescopic beams, which extend from the same side of the supporting beams, are each connected in pairs to an end plate. On one of the end plates the above-mentioned selfbraking screw jacks are mounted. By means of worm gears inside the beams, these screw jacks are able to influence the distance between the parallel end plates. Otherwise, the end plates are formed as a U-formed yoke over the pipeline, the opening of the yoke being directed downwards.

The end plates are also provided inwardly, towards the pipeline, with slots which fit the above-mentioned pushing lugs.

The invention will now be further described, by way of example, with reference to the accompanying drawing, in which: Figure 1 shows a part of a pipe system on a seabed with a pipe module in the form of a valve, Figure 2 shows a supporting plate constituting part of a tool according to the invention, and Figure 3 shows a telescopic frame which also forms part of a tool according to the invention.

Figure 1 shows, mounted on a bottom plate 1, a part of an underwater pipeline system and a pipe module in the form of a valve 2 with clamp connection pieces 3 and 4.

The pipeline system is connected, by way of pipe ends 5 and 6, to the respective clamp connection pieces of the pipe module. The pipe ends are formed with clamp connection pieces, shown at 7. Between them is a sealing gasket 8. The pipe ends and the pipe modules are connected together with a clamp coupling, consisting of a lower half 9 and an upper half 10 (shown divided for clarity on the right). A screwed-together clamp coupling is shown on the left at 11 at the pipe module's connection with the pipe end 5.

The two lower coupling halves are each supported and guided in their positions with the aid of supports 12 and 13, respectively, retractably mounted on the bottom plate 1.

The clamp coupling 9, 10 shown in Figure 1 has two screws 14 and 15 and the clamp coupling 11 also has two corresponding screws 16 and 17. The screws are formed with extended screw heads exhibiting a conical tip.

In addition, each upper clamp coupling half is provided with a gripper 18, 19, respectively, which assists in forming a connection to a supporting plate shown in Figure 2, as will shortly be explained. The grippers 18, 19 are useful, but not essential.

The pipes leading to the pipe module each have an attachment device 20 and 21 securing them firmly to the plate 1. The pipe system and the attachments are formed such that the pipe ends and the pipelines can be displaced somewhat in the lateral direction relative to the plate 1.

This tolerance in lateral position is limited by a stop lug 22 and a stop lug (not shown), diametrically located in relation to stop lug 22, on one of the pipe ends making contact with the attachment device 20, and in the opposite direction by a stop lug 23 and a stop lug (not shown), diametrically located in relation to stop lug 23, on the other pipe end making contact with the attachment device 21.

Between the stop lugs 22, 23 and the respective clamp connection piece, each pipe end is provided with a number of pushing lugs. In the embodiment shown in Figure 1, three such pushing lugs are provided at each of two locations, although only two of the lugs (24, 25 and 26, 27) in each of these locations can be seen in Figure 1.

Figure 1 also shows that the pipe module (i.e. in the example shown the valve 2) has a gripping head 28.

The tool used to operate on the pipe module of Figure 1 consists of a supporting plate 29 shown in Figure 2 and a telescopic frame shown in Figure 3, both of which are provided with a number of devices to provide the required functioning of the tool.

Associated with the supporting plate 29 of the tool part shown in Figure 2 are a number of fixing devices directed towards a tool carrier (not shown). The fixing devices shown are three worm screws 30, 31 and 32. A hydraulic, lockable coupling 33 is also provided, which is adapted for engaging the pipe module in question (i.e. the gripping head 28 according to Figure 1). Hydraulic couplings for engaging gripping devices 46, 47 of the telescopic frame shown in Figure 3 are indicated at 34 and 35 in Figure 2.

Hydraulically operated screwdrivers for the screws of the clamp couplings 9, 10 and 11 are shown at 36, 37 and at 38, 39 in Figure 2.

A hydraulic motor for driving screw jacks on the telescopic frame is shown in Figure 2 at 40 and the connection of the motor to the telescopic frame is shown at 41.

If the upper clamp coupling halves are provided with grippers 18 and 19 as shown in Figure 1, the corresponding connection devices are provided at 42 and 43 on the supporting plate 29.

A preferred embodiment of the telescopic frame is shown in Figure 3. As mentioned it comprises two telescopic arms, which each include a respective supporting beam 44 or 45. A gripper 46 or 47 is connected to each supporting beam for connection with the supporting plate 29 by way of the hydraulic couplings 34 and 35 mounted on the plate.

Inside each supporting beam 44 and 45, two telescopic beams are located. Figure 3 shows telescopic beams 48 and 49 extending from the supporting beam 44 and a telescopic beam 50 extending from the supporting beam 45. A further telescopic beam 51 (not shown), corresponding to telescopic beam 48, is also provided, extending from the unseen end of the supporting beam 45.

The telescopic arms 49, 50 and 48, 51 are interconnected by means of two parallel end plates 52 and 53, which are perpendicular to the telescopic arms, the end plate 52 thus being connected to the telescopic beams 49 and 50 and the end plate 53 being connected to the telescopic beams 48 and 51.

To one of the end plates, in the example shown in Figure 3 the end plate 52, reversible self-braking screw jacks 54 and 55 are connected, one for each telescopic arm.

The telescopic drive, i.e. the displacement of the end plates towards and away from each other, respectively, takes place via the screw jacks using the hydraulic motor 40 and the coupling 41 shown in Figure 2 acting with the corresponding coupling 56 shown in Figure 3. This connection is so flexible that the end plate 52 is able to move somewhat relative to the supporting plate 29 without loss of a drive connection. The screw jacks are self-braking in the sense that they cannot be rotated by pressure applied to the end plates 52, 53, only by means of rotating the coupling 56. The end plates 52, 53 are internally provided with slots which are capable of surrounding the pushing lugs 24, 25 and 26, 27 on the pipe ends. Each end plate is also provided with supporting legs 57, 58 and 59, 60.

In addition to the tool described, the invention also comprises a method for replacement of a pipe module.

On the surface platform or corresponding ship belonging to the relevant production equipment, the tool, i.e.

the supporting plate 29 connected to the telescopic frame, is provided with a lockable coupling adapted to the gripping head on that pipe module which is to be replaced or acted on in some way. The tool is connected by means of the worms 30, 31 and 32 to an existing tool carrier. By means of this tool carrier the tool is lowered towards the seabed and is positioned against existing guide posts provided for that purpose. This causes the end plates 52, 53 of the tool with the respective internal slots to surround the pushing lugs of the pipe ends. The lockable hydraulic coupling 33 of the tool engages the gripping head 28 of the pipe module. The hydraulic screwdrivers 36, 37 and 38, 39 surround the screw heads of the screws 14, 15 and 16, 17, respectively.If the upper clamp coupling halves are provided with grippers 18 and 19, these are connected to the corresponding couplings 42 and 43 on the tool. The hydraulic motor 40 is connected to the screw jacks by means of the couplings 41 and 56.

First the hydraulic screwdrivers are activated, the screws 14-17 of the clamp couplings then being withdrawn.

The upper clamp coupling halves with screws are raised against the supporting plate and the lower clamp coupling halves are lowered by means of the supports 12 and 13 to such an extent that the clamp connection pieces 7 are free to move in the lateral direction. Then the screw jacks are activated, causing the end plates 52 and 53, by means of the internal slots and the push lugs 24, 25 and 26, 27 on the pipe ends, to disconnect the pipelines and push them apart until the stop lugs 22, 23 make contact with the attachment devices 20, 21 of the pipes. this causes the pipe module to become freely suspended from the tool. If the upper clamp coupling halves are not provided with grippers 18, 19 and the supporting plate 29 does not have corresponding coupling devices, the pipe ends can still be pushed apart, after the screws of the clamp couplings have been unscrewed.The upper clamp coupling halves will then be held in position in the lateral direction with the aid of the screwdrivers. However, they will be capable of being lifted against the supporting plate as the pipe ends are being pulled apart because of the confronting conical surfaces of the clamp connection pieces and the clamp coupling halves.

The supporting plate 29 is disengaged from the tele scopic frame by opening the couplings 34, 46 and 35, 47.

The frame is now standing on the bottom plate and is supported by the legs 57-60 of the end plates. Then the supporting plate 29 with the pipe module and the upper clamp coupling halves are lifted with the tool carrier up to the surface platform or to a surface-based ship for replacement or other action on the recovered pipe module.

After a repaired or replacement pipe module has been mounted in the supporting plate 29, this is lowered with the tool carrier towards the seabed and, with the aid of the previously used guide posts, the supporting plate is repositioned against the telescopic frame and the pipe ends.

To minimise the risk of the pipe module, the sealing gaskets 8 and the clamp connection pieces 7 being damaged in the positioning, the bottom plate 1 is provided with two guiding supports 61 and 62 (see Figure 1) with a V-shaped opening designed to locate the clamp connection pieces 3 and 4 of the pipe module. The clamp connection pieces are provided with guiding projections 63, 64 facing the bottom plate 1, which fit a respective slot at the bottom of each V-shaped slot. When the pipe module, after being lowered, comes into contact with the guiding supports, if it is not correctly positioned, it will slide on any of the V-shaped sides of the guiding supports 61, 62 and finally arrive at a position where the guiding projections 63, 64 are at the bottom of the V-slots. Now the supporting plate 29 can be connected with the telescopic frame resting on the bottom plate 1.

The screw jacks 54, 55 are then activated in such a direction that the end plates 52, 53 and, with these, the pipe ends of the pipe system are drawn towards the replaced pipe module so as to obtain good contact between the clamp connection pieces 7 of the pipe module and the clamp connection pieces of the pipe ends with an intermediate new sealing gasket 8.

If the upper clamp coupling halves have been raised towards the supporting plate by means of their own grippers and corresponding connection devices on the supporting plate, they are now lowered. The screwdrivers of the tool are then activated to connect together the lower and upper clamp coupling halves, thus ensuring good sealing between the pipe module and the pipe ends from the pipeline system leading to the pipe module.

If the upper clamp coupling halves have only been connected to the supporting plate by means of screwdrivers and the screws of the clamp couplings, they will now, after the clamp connection pieces have been joined together, be correctly positioned and the screwdrivers can be activated.

After having disconnected all the connections between the tool and the pipe module, clamp couplings, etc., the tool can be raised to the surface again with the aid of the tool carrier.

In other respects the tool is equipped with conventional control and operating devices for executing various orders and commands which, via the tool carrier and a control cable, come from a surface-based central operating unit.

Components such as couplings, screw jacks, screwdrivers, and so on, may, of course, be formed in many different ways within the scope of the invention.

Claims (11)

1. A method for the diverless replacement of a pipe module forming part of a pipeline system disposed on a bottom plate located on a seabed, which method comprises the steps of lowering a two-part tool having an upper part and a lower part down to the pipe module, securing the module to said upper part, using the tool to uncouple the module from adjacent regions of the pipeline system, using said lower part to move said regions of the pipeline system connected to said module apart relative to the bottom plate to thereby release the module, separating said two parts of the tool so that said upper part lifts the module while the lower part remains with the said regions of the pipeline system on the bottom plate, lifting the removed module for service or replacement, lowering a serviced or replaced module with the upper part of the tool back down to the lower part of the tool, inserting the serviced or replaced module between the moved apart regions of the pipeline system, moving said regions back into contact with the serviced or replaced module using the lower part of the tool, using the tool to recouple the serviced or replaced module to said adjacent regions, releasing said upper part from the serviced or replaced module, and lifting said two parts from the seabed.

2. A method according to claim 1, in which the bottom plate includes V-shaped grooves to correctly locate the serviced or replaced module between the moved-apart regions of the pipeline system.

3. A method according to claim 1 or claim 2, in which the upper part of the tool includes a motor for drivably connecting screw jacks on said lower part, which screw jacks effect the moving apart and moving together of the said regions.

4. A method according to any preceding claim, in which the pipe module is provided with a gripping head, to engage a lockable coupling on the upper part of the tool.

5. A method according to claim 2, in which the shaped grooves are provided with slots which fit guiding projections on the pipe module.

6. A method according to any preceding claim, in which the pipeline system with pipe ends facing the pipe module is secured to the bottom plate by means of attachment devices allowing the pipe ends to be displaced in the lateral direction, the pipe ends facing the pipe module being formed as clamp connection pieces, and the clamp connection pieces of the pipe ends are provided with stop lugs to limit the outward movement of the pipe ends.

7. A method according to any preceding claim, in which clamp connection pieces of the pipe ends, and pairwise associated clamp connection pieces of the pipe module are each surrounded by a clamp coupling provided with screws, each clamp coupling consisting of a lower half which has a support against the bottom plate, and an upper half which is provided with a gripper adapted to be engaged by said upper part of the tool.

8. A method according to any preceding claim, in which the lower part of the tool has end plates adapted to engage respective pushing lugs of the pipe ends and supporting legs on which it can rest on the bottom plate.

9. A method for the diverless replacement of a pipe module substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawing.

10. A tool for replacement of a pipe module forming part of a pipeline system disposed on a bottom plate located on the seabed, the tool comprising a supporting plate and a telescopic frame restable on the bottom plate, the supporting plate being provided with a lockable coupling for engaging a gripping head on the pipe module, a hydraulic motor for driving screw jacks on the telescopic frame, screwdrivers, connection devices between the supporting plate and the corresponding grippers on the telescopic frame, connection devices between the supporting plate and corresponding grippers on clamp couplings between the pipe module and pipe ends leading to said pipe module, a connection device between the hydraulic motor and the corresponding connection device on the screw jacks on the telescopic frame and connection devices on the tool carrier, the telescopic frame comprising two parallel end plates, between which there are two parallel telescopic arms arranged perpendicular to the end plates, each of said arms consisting of a supporting beam telescopically receiving two telescopic beams which are adapted to be operated by a respective one of the screw jacks, the supporting beams being provided with connection devices facing the supporting plate, and the interior of the end plates is provided with slots adapted to surround pushing lugs on the pipe ends, the end plates being further provided with supporting legs for resting on the bottom plate.

11. A tool for the diverless replacement of a pipe module substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawing.