WO2013050411A2

WO2013050411A2 - Underwater vehicle docking station

Info

Publication number: WO2013050411A2
Application number: PCT/EP2012/069522
Authority: WO
Inventors: Marcus FURUHOLMEN
Original assignee: Aker Subsea As
Priority date: 2011-10-03
Filing date: 2012-10-03
Publication date: 2013-04-11
Also published as: NO20111340A1; WO2013050411A3

Abstract

A subsea well template (1, 1') comprising one or more well slots (3, 3'). One or more of the well slot(s) is provided with an underwater vehicle docking station (21).

Description

Underwater vehicle docking station

The present invention relates to an underwater vehicle docking station and a subsea well template provided with such an underwater vehicle docking station. It also relates to a method of installing an underwater vehicle docking station.

Background

It is known to dock an underwater vehicle, such as a remotely operated vehicle (ROV) and an autonomous underwater vehicle (AUV) in a docking station arranged on the seabed. When arranged in a docking station, the vehicle may charge its batteries and may also communicate with an operator or associated equipment. Thus, the docking station needs a power supply and communication channels for communication with the operator. Moreover it also needs a communication interface to the vehicle itself as well as power supply interface to the vehicle.

Patent application publication GB 2453645 describes an AUV docking station arranged on the seabed. The docking station is lowered down to the seabed by a supply ship, with or without the AUV mounted in the docking station. US patent application publication US2002040783 shows a plurality of well templates having one well slot each (cf. Fig. 1 ). Each of the well slots is provided with well equipment, i. e. a Xmas tree (30). Close to one well slot there is shown a docking station. Patent application publication GB2210838 also describes an underwater vehicle (ROV 8) and a docking station (garage structure 10). This docking station is suspended in a lifting cable (1 1 ).

As the seabed is often soft and muddy, one needs large foundation structures in order to deploy subsea equipment on the seabed. One may for instance use a suction anchor. Also, in areas where there is trawling, protection structures are required in order to protect the subsea equipment from damage. Protection structures are also required for dropped object protection. It is an object of the present invention to provide an underwater vehicle docking station without addition of large and costly structures.

The invention

According to a first aspect of the present invention there is provided a subsea well template which comprises one or more well slots. According to the invention, one or more of the well slot(s) is provided with an underwater vehicle docking station. Preferably the one or more well slots is/are provided with a wellbay insert (WBI) which provides interface support for subsea equipment including a Xmas tree and a blowout preventer, as well as interface support for drilling. The wellbay insert(s) are provided with guide posts and/or guide post supports, which guide posts are adapted to guide equipment down into the well slot. Furthermore, the underwater vehicle docking station is advantageously arranged on one of the one or more wellbay inserts.

In one embodiment the underwater vehicle docking station comprises a plurality of guiding elements adapted to guide the underwater vehicle docking station when lowered onto the wellbay insert. The guiding elements will then engage with guide posts that extend up from the wellbay insert. One may of course arrange more than one vehicle docking station on the subsea well template, for instance two. In such an embodiment one could imagine arranging one docking station on top of the other. The two docking stations could then be guided on the same guide posts.

The underwater vehicle docking station can be connected to a subsea production control system through a communication interface and a power interface. The interface may be a combined power and communication interface, or a separate power interface and a separate communication interface.

In a further embodiment, the well template is a satellite template comprising only one well slot and one associated wellbay insert. According to a second aspect of the present invention, there is provided an underwater vehicle docking station which is adapted to receive an underwater vehicle. According to the second aspect of the present invention, the docking station comprises guiding elements which are adapted to engage with upwardly extending guide posts.

In an embodiment of the second aspect of the invention, the guiding elements are adapted to engage with guide posts of a standardized size wellbay insert. According to a third aspect of the present invention, there is provided a method of installing an underwater vehicle docking station on the seabed. The method comprises lowering the underwater vehicle docking station on a suspension string through a body of water towards the seabed. According to the third aspect of the invention, the method further comprises

b) aligning the underwater vehicle docking station with a plurality of guide posts extending upwards from a wellbay insert; and

c) lowering the underwater vehicle docking station further and landing it onto the wellbay insert while guiding elements of the underwater vehicle docking station are in engagement with the guide posts.

When the docking station has been landed on the wellbay insert, the suspension string, such as a lifting cable, can be detached from the docking station.

According to an embodiment of the third aspect of the invention, the wellbay insert is arranged on a well slot of a subsea well template. The subsea well template may comprise a plurality of well slots.

The well template is a subsea structure provided with one or a plurality of wellbay inserts (WBI). The well template may for instance comprise four well slots and an associated manifold. In such an embodiment, each of the four well slots is typically provided with a wellbay insert (WBI), through which the operator may drill a subsea well. The WBI also works as a guiding element and interface for blowout preventers (BOP) and Xmas trees. According to the invention, a spare well slot may be provided with an underwater vehicle docking station, which advantageously can be landed on the WBI of the spare well slot in question. A wellbay insert is often also referred to in the art as a production guide base or a permanent guide base (PGB). Example of embodiment

Having described the invention in general terms above, a more detailed example of embodiment will be given in the following with reference to the drawings, in which Fig. 1 is a perspective view showing a known well template provided with

wellbay inserts (WBI);

Fig. 2 is a perspective principle view of a wellbay insert provided with four guide posts and a docking station being lowered onto the WBI, as well as an AUV;

Fig. 3 is a side view of the elements shown in Fig. 2;

Fig. 4 is a perspective view of a second embodiment according to the invention;

Fig. 5 is a principle top view of a well template with four well slots of which one is provided with an underwater vehicle docking station; and

Fig. 6 is a principle top view of two well templates each having one well slot, of which one of them is provided with an underwater vehicle docking station.

Fig. 1 shows a traditional well template 1 having four well slots 3 which each is provided with a wellbay insert 5 (WBI). Between two pairs of well slots 3 there is arranged a manifold 4. Each WBI 5 has four upwardly extending guide posts 7 and a centrally arranged guide funnel 9 for landing of a Xmas tree or a blowout preventer. When the well has been drilled, a conductor casing extends into the seabed down from the guide funnel 9 (see Fig. 2 and Fig. 3).

Fig. 2 and Fig. 3 show a wellbay insert 5 in more detail, without the surrounding well template 1 . Also shown is an AUV docking station 21 and an AUV 31 . In this embodiment the AUV docking station 21 has the shape of a rectangular box with an open end 23 which is adapted to receive the AUV 31 . As is indicated in Fig. 2, the AUV docking station 21 is adapted to be guided down onto the WBI 5 on four guide posts 7. The guide posts 7 extend up from the wellbay insert 5 and are typically arranged with a standardized mutual distance. Typically the wellbay insert 5 may be designed according to the ISO 13628-4 standard, in which the four guide posts 7 are arranged at each corner of a square having sides of 2586 mm.

When lowering the AUV docking station 21 onto the WBI 5, the four guide posts 7 will be inserted into four guiding elements in the form of guiding sleeves 25 which are attached to the main body of the AUV docking station 21 . Thus, when lowering the AUV docking station 21 down on the guide posts 7 and onto the WBI 5, the operator can install the AUV docking station 21 in a predetermined and known position on the well slot 3 of the well template 1 . Aligning the docking station 21 with the guide posts 7 may be performed with an ROV. Lowering the AUV docking station 21 may be done by means of a lifting cable (not shown). Once the AUV docking station 21 is installed on the WBI 5, the lifting cable can be detached from the docking station.

A person skilled in the art should appreciate that in stead of four guide posts 7, there could also be arranged another number of guide posts 7, such as two. It is preferred that at least two guide posts 7 are used in order to ensure correct orientation of the AUV docking station 21 .

When installing the AUV docking station 21 to the WBI 5, it may advantageously be connected to a power supply interface and communication interface (not shown) of the well template 1 . Such interfaces are typically present for potential future installation of a Xmas tree along with associated equipment. For instance, an underwater vehicle may connect the AUV docking station 21 to the said interfaces by means of one or more jumpers. The equipment to which the AUV docking station 21 is connected will typically be arranged on the manifold 4. When the AUV docking station 21 is installed on the WBI 5 of a spare well slot 3, the AUV 31 can hover into the AUV docking station 21 through the open end 23 and connect to docking station power and communication interfaces (not shown). Such interfaces may for instance be inductive couplers. In another embodiment of the present invention, the well template 1 ' exhibits only one well slot 3' (a satellite template). Such an embodiment is shown in Fig. 4. As with the embodiment described with reference to Fig. 1 , the well slot 3' is provided with guide posts 7' and a wellbay insert 5', and is in the same manner suited to receive a docking station 21 as described above with reference to Fig. 2 and Fig. 3.

In yet an embodiment the docking station 21 is landed on a wellbay insert 5 which is not arranged in association with a well template. The equipment shown in Fig. 4 could thus in principle also illustrate a wellbay insert 5 which is not arranged in a well template. The framework surrounding the wellbay insert 5 could thus be an appropriate framework adapted to support the wellbay insert 5 on the seabed. For instance, the wellbay insert 5 could be installed on the seabed on the upper portion of a suction anchor, which is known to the person skilled in the art.

Fig. 5 and Fig. 6 schematically illustrate a possible power distribution for the embodiments shown in Fig. 1 and 4, respectively. Fig. 5 shows a schematic example of the electric distribution on a well template 1 having four well slots 3. An umbilical 41 leads to an umbilical termination head 43 on the well template 1 . A jumper is extended from the umbilical termination head 43 to a subsea router module 45 arranged on the manifold 4. From the subsea router module 45, four electric jumpers 47 distribute power and communication channels to each of four subsea control modules 49. At the three well slots 3 provided with Xmas trees 57, the subsea control modules 49 are arranged to the Xmas trees 57. One of the well slots 3 is provided with the AUV docking station 21 , as described above. The AUV docking station 21 is also provided with a subsea control module 49, which is connected to the subsea router module 45 by means of its associated jumper 47. The connection between the subsea control modules 49 and the subsea router module 45 can preferably be established by using an ROV (not shown) to connect the said jumpers 47. The jumpers will typically be equipped with wet-mate connectors, as is known to the person skilled in the art. In this way, the AUV docking station 21 is connected to a subsea production control system.

An AUV 31 is schematically indicated and is about to hover into the AUV docking station 21 .

Fig. 6 shows another principle example of electric distribution. In this

embodiment, an umbilical 41 leads to the subsea router module 53, similar to the subsea router module 45 shown in Fig. 5. From the subsea router module 53, two electric jumpers 55 lead to two separate well templates 1 '. Each well template 1 ' has only one well slot 3'. One of the well templates 1 ' is provided with a Xmas tree 57, whereas the other is provided with the AUV docking station 21 , as described above. The Xmas tree 57 and the AUV docking station 21 are provided with a subsea control module 49', to which the electric jumpers 55 connects.

For satellite embodiments, as the one described with reference to Fig. 6, the WBI is typically called a "production guidebase" or an "integrated guidebase". It will be understood by the person skilled in the art, that the docking station landed on the WBI 5 can be any kind of docking station for an underwater vehicle, and not only for an AUV as shown in the example above.

In stead of the rectangular box-shaped structure of the AUV docking station 21 described in the embodiment above, the docking station may be designed in another way. For instance, it may be without any top cover, as the well slot 3 where it is landed may be protected by the hatches and structure of the well template 1 .

Claims

1 . A subsea well template (1 , 1 ') comprising one or more well slots (3, 3'),

characterized in that one or more of the well slot(s) is provided with an underwater vehicle docking station (21 ).

2. A subsea well template according to claim 1 , characterized in that the one or more well slots (3) is/are provided with a wellbay insert (5) which provides interface support for subsea equipment including a Xmas tree and a blowout preventer, as well as interface support for drilling, which wellbay insert(s) (5) are provided with guide posts (7, T) and/or guide post supports, and that the underwater vehicle docking station (21 ) is arranged on one of the one or more wellbay inserts (5).

3. A subsea well template according to claim 2, characterized in that the underwater vehicle docking station (21 ) comprises a plurality of guiding elements (25) adapted to guide the underwater vehicle docking station (21 ) when lowered onto the wellbay insert (5), as the guiding elements (25) engage with guide posts (7) that extend up from the wellbay insert (5).

4. A subsea well template according to one of the preceding claims, characterized in that the underwater vehicle docking station (21 ) is connected to a subsea production control system through a communication interface and a power interface.

5. A subsea well template according to one of the preceding claims, characterized in that the well template is a satellite template (1 ') comprising only one well slot (3') and one associated wellbay insert (5').

6. An underwater vehicle docking station (21 ), adapted to receive an underwater vehicle (31 ), characterized in that it comprises guiding elements (25) which are adapted to engage with upwardly extending guide posts (7).

7. An underwater vehicle docking station (21 ) according to claim 6, c\ that the guiding elements (25) are adapted to engage with guide posts (7) of a standardized size wellbay insert (5).

8. A method of installing an underwater vehicle docking station (21 ) on the seabed, comprising

a) lowering the underwater vehicle docking station (21 ) on a suspension string through a body of water towards the seabed;

characterized in that the method further comprises

b) aligning the underwater vehicle docking station (21 ) with a plurality of guide posts (7) extending upwards from a wellbay insert (5); and

c) lowering the underwater vehicle docking station (21 ) further and landing it onto the wellbay insert (5) while guiding elements (25) of the underwater vehicle docking station (21 ) are in engagement with the guide posts (7).

9. A method according to claim 8, characterized in that the wellbay insert (5) is arranged on a well slot of a subsea well template (1 , 1 ').

10. A method according to claim 9, characterized in that the subsea well template (1 ) comprises a plurality of well slots (3).