MX2008010296A - Crane assisted pipe lay - Google Patents

Abstract

The present invention relates to a method for laying a pipeline using a vessel (1) comprising a crane (2) comprising the following steps lifting a new pipe section (8) using the crane, placing a new pipe section on an existing pipeline (9), lining up the new pipe section with respect to the existing pipeline, welding the new section to the existing section, lowering the joined new section and the existing pipe, supporting the joined new section so that the crane is free to lift another new section. The invention further relates to a pipe-laying vessel for carrying out such method.

Description

PROOF OF TUBE ASSISTED WITH CRANE DESCRIPTIVE MEMORY The present invention relates to a method for laying a pipe using a boat and a crane. The invention also relates to a boat for laying pipes. In the maritime industry there is a need for underwater pipelines. These subsea pipelines can be provided by joining pipe sections in a substantially vertical position to form a pipeline that is lowered from a vessel to a subsea bottom part, for example, the bottom of the sea. In such a tube laying method, which is commonly referred to as a J-laying method, a plurality of tube sections welded together forming a part of the pipe are hung down from a boat in a substantially vertical direction in where an upper end of the most recently joined pipe section is to be welded to a lower end of a new pipe section that is aligned on said upper end. The new pipe sections that are to be joined to the catenary of the section of pipe that hangs from the boat can be on a scale of 24 to 120 meters. The joining of the new section requires an installation to hold the pipe section during welding and to lower the connected pipe section to make it possible to join other pipe sections.

This installation, in the J-lay method, generally a J-lay tower is large and generally requires a considerable amount of space on the roof. Not all boats have this space available and other equipment has to be omitted in the case of the pipe laying installation for example a J-lay tower is required to have enough space in the deck available to place such a facility. In addition, the required position of the pipe laying facility, for example in the bow or stern of the boat, may also be a preferred position for other boat equipment such as cranes. In such a case it may be desired to have two pipe laying installations and the crane in substantially the same position on the roof, which is generally only possible when exchanging the pipe laying installation and the crane when one of both is required. The other installation has to be temporarily stored anywhere, for example on the deck of the boat. This invention provides a method for laying pipes on the seabed and a pipe laying vessel configured to lay pipes on the seabed. This invention provides a method for laying a pipe at the bottom of the sea in which a crane is used, the method comprises the steps of: raising a new pipe section using the crane, placing a new pipe section in an existing pipe, align the new section of tube with respect to the existing tube, weld the new section to the existing tube, lower the new section together and the existing tube, support, for example by means of clamp, the new section joined so that the crane is free to raise another new section. When using a crane to support an upper end of the new pipe section, one or more of these actions can be carried out without the need to separate the equipment to hold the new pipe section and / or the existing pipe. For example, a tower, such as a J-lay tower to hold the new tube section during alignment and welding can be omitted. Also an upper clamp block or tensioner may not be required anymore when the crane takes the task of these parts. Therefore, when using the crane for one or more actions, separate and relatively expensive systems can be omitted for these actions and the deck space is kept free for other purposes. In particular, the crane can be placed in a preferred position since the presence of a complete J-lay tower is no longer required. In one embodiment, the crane is used to hold the new tube section during the welding step. The crane can support the new pipe section during the joining of this pipe section with another section of pipe, in particular the upper pipe section of a catenary of pipe sections previously joined to form a pipe to be laid on the pipe. bottom of the sea.

In one embodiment, the crane is used to lower the pipe including the new welded section. After welding, the crane can hold the upper end of the newly joined tube section. The existing pipe can be supported by a clamp device placed on the boat. To lower the pipe to make it possible to join a new section of pipe, the pipe can be lowered using the crane. The crane can lower the upper end of the newly joined tube section after the clamping device has withdrawn the clamping force so that the movement of the pipe with respect to the clamping device is possible. When the crane has lowered the pipe to the desired position, the clamp device can embrace the upper end of the newly attached pipe section with which it holds the pipe. In the following, the crane can release the pipe and is free to be used for another action, for example to take a new section of pipe to be joined to the pipe. In one embodiment, the crane can be used to abandon and recover the pipe. In the case where it is desired to leave the pipeline, for example due to weather conditions, the pipeline may be abandoned when using the crane. This can be advantageous in particular in this invention since the crane can support the pipe during a considerable part of the pipe laying process. When the crane already holds the pipeline, the abandonment can be carried out in an efficient way. When pipe laying can be continued, for example when climatic conditions have improved, the pipeline can be recovered by means of the crane. In one embodiment, the crane can be used to move the entire pipeline from the vessel for pipe laying to its final suspension location in a production and / or storage facility. This may be advantageous in this invention since the crane may be connected to the pipe during the completion of pipe laying activities. In one embodiment, the crane holds the upper end of a new tube section from the moment the tube section rises from its storage location on the cover until it is huddled into the suspension clamp after it has been welded to the existing pipeline. In one embodiment, all the aforementioned actions are carried out by means of the crane. However, it is also possible that some of these actions are carried out through other devices. The invention provides a tube laying vessel comprising: a crane, a pipe installation frame, a suspension bracket for supporting an existing pipe, and a welding station, where the crane is adapted to perform one or more of the following actions: lift and load a new pipe section into the pipe installation frame, hold the new pipe section during welding and lower the pipe including the new welded section . The crane is placed in the vessel preferably relatively close to the location where the pipe hangs from the boat so that the crane can perform the actions that are carried out on vessels for conventional pipe laying by means of a laying tower of pipe is in particular a J-lay tower. The pipe laying is preferably carried out according to a J-laying method in which the new pipe sections are joined to the existing pipe in a substantially vertical position or close to the vertical. In an alternative mode, the crane to be used for pipe laying can be placed in another vessel. The absence of a pipe laying tower makes it possible to place other equipment on the deck of the vessel for pipe laying, since this space is not taken by means of the crane on another vessel. The pipe installation frame is a frame which is configured to stabilize or guide at least a part of a new pipe section. In addition, the pipe installation frame may carry one or more units of equipment for laying the pipes such as a pipe clamp. suspension and / or a welding station. In one embodiment, dimensions of pipe installation frame are substantially smaller than a conventional pipe laying tower, whereby in particular vertical dimension of pipe installation frame may be less than length of a pipe section. that is going to join existing pipeline. pipe installation frame may for example carry welding station, suspension bracket and / or an alignment device to align a lower end of a pipe section with upper end of existing pipe before attaching e ends by means of a suitable type of welding or o joining method to join tube and pipe section. In one embodiment, pipe installation frame can be tilted so that angle of a pipe section to be connected to existing pipe can be adjusted and placed in line with orientation of existing pipe. In an alternative embodiment, o means such as a sleeper are provided to adjust angle of pipe from for example a substantially vertical position in pipe installation frame at an angle in line with catenary to sea floor. pipe installation frame may comprise one or more rollers or o guiding devices for stabilizing and / or guiding position of pipe section. welding station is provided to make it possible to weld one end of a new pipe section to existing pipe. welding can be any welding procedure known in art. In one embodiment, vessel may comprise an alignment device for aligning new section with existing pipeline. With such an alignment device it can be made easier to align new pipe section supported by a crane with respect to upper end of existing pipe which can be supported by means of suspension clamp. In one mode, crane is configured to abandon and recover pipe. Since crane is adapted to support one end of a section of pipe, crane can be used in case an abandonment and recovery procedure is desired for example caused by bad wea conditions. crane can be used to lay pipe on seabed or to lift it from seabed. In one embodiment, crane is configured to move entire pipeline from vessel for pipe laying to a suspension location in a production and / or storage facility. O characteristics and advantages of method and boat for laying a tube according to invention are fur explained in attached drawings in which: Figure 1 shows an embodiment of invention according to a first method; Figure 2 shows an embodiment of invention according to a second method; Figures 3a-3e show different stages of a method for laying pipes according to an embodiment of invention; and Figure 4 shows tube laying vessel of Figure 1 used for an abandonment or transfer procedure. Figure 1 shows a boat for laying of tube 1 according to invention. vessel 1 is configured to lay tubes on seabed. vessel 1 comprises a crane 2, a pipe installation frame 3, a welding station 4, and a suspension bracket 5. crane 2 is configured to elevate pipe sections to be joined in pipeline. example a storage location on cover in a substantially vertical position to pipe installation frame for placing a lower end of pipe section in vicinity of upper end of existing pipe. existing pipe forms a catenary at bottom of sea and comprises a number of tube sections previously attached to each o. existing pipe 9 can be supported by means of a suspension bracket 5. pipe installation frame 3 is provided to guide and stabilize pipe section 8. pipe installation frame 3 can carry the welding station 4 and the suspension bracket 5. The tubena 3 installation frame can also carry additional equipment required for pipe laying such as alignment devices, welding inspection stations, field joint lining station and similar. All the previous equipment can be mounted directly on the boat or in another construction. The pipe installation frame 3 can be inclined on a horizontal axis to make it possible for the inclination of the pipe installation frame 3 to be adapted to the starting angle a of the catenary towards the sea floor. This starting angle a is determined by the vertical weight in the pipe 9 suspended from the suspension bracket 5 and the horizontal thrust exerted on the pipe 9 by means of the pipe laying vessel 1. Since the pipe installation frame can be tilted, sleeper 6 can be omitted in this mode. The crane 2 comprises a crane block 7 having a pipe manipulator clamp for embracing an upper end of a pipe section 8. With this pipe manipulator clamp one end of the pipe section 8 can be embraced to raise the pipe section to a desired location or position. The crane 2 can be used to hold the pipe section during welding of the new pipe section 8 to the existing pipe 9. The crane can also be used to lift other objects that have to be lifted.

The tube sections 8 can, for example, be 24-120 meters long, preferably 48-96 meters long. Generally, the pipe installation frame 3 is smaller and can have a height of 5-40 meters, preferably 10-25 meters. Figure 2 shows an alternative embodiment of a tube laying method according to the invention. In this embodiment, the pipe installation frame 3 is not inclined and may not be tiltable. A sleeper 6 is used to support the transition curve of the pipe from the vertical directed pipe installation frame 3 to the starting angle a of the catenary to the sea floor. With respect to Figures 3a-3e, one embodiment of a tube laying method according to the invention will be described. Figure 3a shows how a new pipe section 8 to be joined to the existing pipe 9 moves with its lower end towards the upper end of the upper pipe section of the existing pipe 9 (as indicated with the arrow A). The existing pipe 9 is clamped in a suspension bracket 5 which in this case is located near the lower end of the installation frame 3. The pipe section 8 is supported according to the invention by means of the crane 2. One second step of loading the new tube section is shown in figure 3b. The new pipe section is stabilized by closing a part of the pipe frame so that the pipe section is kept within a space. The pipe installation frame 3 comprises a number of rollers 10 for guiding the tube section 8 to enable vertical movement of the tube section in this space. In Figure 3c it is shown that the new tube section 8 is lowered (arrow B) by means of the crane 2 towards the upper end of the existing pipe 9 held in the suspension bracket 5, and placed in an alignment device 1 1, for example a so-called external alignment tool. The new section 8 is further lowered in the alignment device 1 1, the upper part of the new section is preferably held by means of the crane 2 and is aligned so that the lower end of the new section 8 is placed substantially exactly at the upper end of the existing pipe 9 to enable welding. The accuracy of the alignment device 1 1 can generally be within a range of millimeters. The alignment device 1 1 can place the lower end of the new section with respect to the upper end of the existing pipe by means of translation and rotation. In a next step, shown in Figure 3d, the new section 8 is welded into the existing pipe in the welding station 4. Any suitable welding technique can be used to join the lower end of the pipe section 8 to the upper end of the existing pipe 9 Any other technique for joining the tube section 8 to the existing pipe 9 can also be used. During welding, the tube section 8 can be supported by means of the crane and / or the pipe installation frame. He Alignment device can be removed from the tube section 8 when the welding has been finished sufficiently. After welding, the weld can be checked with nondestructive examination (NDE). Also here the upper end of the new tube section can be supported by means of the crane. Figure 3e shows how, after inspection of the weld, the weld can be coated in a coating station 12. Since the coating station 12 is located lower than the welding station 4, the suspension bracket 5 it is opened and the existing pipe 9 and the new pipe section 8 are lowered (arrow C), preferably by means of the crane to bring the weld to the height substantially of the coating station 12. When the coating process is finished , the crane 2, which holds the upper end of the pipe section 8 can lower the existing pipe 9 including the new section 8 until the upper end of the new section is approximately located at the position of the upper end of the existing pipe during the welder. In this down position, the suspension bracket can be closed in such a way that the existing pipe and the new section are maintained by means of the suspension bracket. Thereafter, the crane 2 can release the upper end of the new section so that the crane is free to raise any other new section that can be placed in the pipe by the clamp. suspension in accordance with the steps described above by the first new section. During the pipe laying procedure as described above, it is also possible that the in-line structures are placed in the pipe and are lowered along with the pipe. While the crane is used to support an upper end of the pipe section 8 through the pipe laying process a complete J-laying tower can be omitted, including the equipment for lowering the pipe and the newly attached pipe section. The combination of the crane 2 and the pipe installation frame 3 requires less deck space than a crane and a conventional J-lay tower. As a result, the crane 2 can be placed in a more preferred position for other operations without the pipe installation frame interfering substantially with such operations, such would be the case when a conventional J-lay tower is present. In figure 4, it is shown how the crane 2 of the boat for laying of tube 1 can be used to abandon and / or retrieve a pipe 20. The same figure 4 can be used to show how a finished pipe is transferred from the boat for laying from tube 1 to a production and / or storage facility (not shown). The pipe 20 is supported by a cable 21 of the crane 2. The pipe 20 is supported by means of a crane block 22. The pipe can be provided by an abandon / recovery or vertical transfer head 23.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1 .- A method for laying a pipe using a boat (1) comprising a crane (2) comprising the following steps: raise a new pipe section (8) using the crane, place the new section of pipe in a pipe existing (9), align the new pipe section with respect to the existing pipe, weld the new pipe section to the existing pipe, lower the new bonded section and the existing pipe, support the new pipe section attached so that the crane is free to raise another new section, characterized in that a pipe installation frame (3) is used to guide and stabilize the new pipe section (8), and said crane (2) supports the new pipe section during the stage of welding and said crane is used to lower the new connected section and the existing pipe (9).

2. - The method according to claim 1, further characterized in that said crane (2) is further used for the abandonment and / or recovery of the pipe (20).

3. - The method according to claim 1, further characterized in that said crane (2) is also used to move the complete pipeline of the vessel for pipe laying (1) to its final suspension location in a production facility and / or storage.

4. - The boat for laying a tube (1) comprising: a crane (2), a pipe installation frame (3), a suspension bracket (5) to support an existing pipe and a welding station (4), characterized in that the crane (2) is adapted to perform the following actions: raise and load a new pipe section (8) into the pipe installation frame (3), hold the new pipe section during welding and lower the pipe including the new welded section.

5. The vessel (1) according to claim 4, further characterized in that the vertical dimension of the pipe installation frame (3) is shorter than the length of a new tube section (8) to be joined. .

6. - The vessel (1) according to claim 4, further characterized in that the crane (2) is adapted to leave and recover the pipe (20).

7. The vessel (1) according to claim 4, further characterized in that the crane (2) is adapted to move the entire pipeline from the vessel for pipe laying to its final suspension location in a production facility and / or storage.

8. - The boat (1) according to claim 4, further characterized in that the pipe installation frame (3) can be tilted.

9. - The vessel (1) according to claim 4, further characterized in that the vessel comprises a stringer (6).

10. - The vessel (1) according to claim 4, further characterized in that the vessel comprises an aligned device (1 1) to align the new section (8) with the existing pipe (9). eleven . - The boat (1) according to claim 4, further characterized in that the crane (2) comprises a tube handling clamp (7) to hold the upper end of a tube section (8). 12. - The vessel (1) according to claim 4, further characterized in that the pipe installation frame (3) comprises one or more rollers (10) to guide the pipe section (8). SUMMARY OF THE INVENTION The present invention relates to a method for laying a pipe using a boat (1) comprising a crane (2) comprising the following steps of raising a new section of pipe (8) using the crane, placing a new section of pipe in an existing pipe (9), align the new section of pipe with respect to the existing pipe, weld the new section to the existing section, lower the new section together and the existing pipe, support the new section together so that the crane is free to raise another new section; The invention also relates to a boat for laying a tube to carry out such a method. 9A P08 / 1220F