Subsea support apparatus for supporting drive means, and driving apparatus incorporating such support apparatus

Abstract

 A driving apparatus (2) for driving pipes (4) into the sea bed is disclosed. The driving apparatus has support arms (20) supporting a drill tower (16) for driving pipes into the sea bed, and a body (6) for supporting a plurality of pipes in cassettes (24). A pipe feeding mechanism feeds pipes to the drill tower (16) and the apparatus is controlled from a vessel located at a sea surface.

Description

[0001] The present invention relates to a support apparatus for supporting drive means for driving a plurality of elongate members into a sea floor, and relates particularly, but not exclusively, to an apparatus for supporting drilling or coring apparatus. The invention also relates to driving apparatus incorporating such support apparatus.

[0002] In drilling or coring operations on the seabed, for example in oil exploration and production, drilling is carried out by means a drill string extending from a semi-submersible vessel located on the sea surface, the drill string extending from the seabed to the vessel. This arrangement has the drawback of being very expensive to implement.

[0003] Preferred embodiments of the present invention seek to overcome the above disadvantage of the prior art.

[0004] According to an aspect of the present invention, there is provided a support apparatus for supporting drive means for driving a plurality of elongate members into a sea floor, the support apparatus comprising:-

a body adapted to support a plurality of said elongate members;

support means provided on said body for supporting said drive means such that a position of said drive means is adjustable relative to said body;

feeding means for feeding a plurality of said elongate members to said drive means; and

control means for enabling control of said support apparatus from a vessel located at a sea surface.

[0005] By providing feeding means for feeding a plurality of elongate members to drive means and control means for enabling control of the support apparatus from a vessel located at a sea surface, this provides the advantage of avoiding the use of a semi-submersible vessel, thereby significantly reducing the cost of drilling or coring operations.

[0006] The feeding means may be adapted to (i) simultaneously feed a plurality of said elongate members, located in position relative to each other by means of locating means, with at least part of said locating means to at least one first location on said body and to (ii) sequentially feed a plurality of said elongate members from at least part of said locating means at at least one said first location to said drive means.

[0007] This provides the advantage of increasing the efficiency of operation of the apparatus, by minimising the distance through which the elongate members must be individually moved.

[0008] The support apparatus may further comprise manipulator means for unloading at least part of said locating means from said body.

[0009] This provides the advantage of enabling the support apparatus to be refilled with elongate members, thereby enabling the apparatus to operate for longer periods and thereby further reducing costs.

[0010] The support apparatus may further comprise at least one engaging portion for engaging lifting means to enable lifting of the support apparatus, wherein said feeding means is adapted to feed a plurality of said elongate members through at least one aperture below said engaging portion in use.

[0011] This provides the advantage of enabling the engaging portion to be located above the centre of gravity of the support apparatus while enabling elongate members to be fed from the rear of the body to the front of the body.

[0012] The support apparatus may further comprise moving means for moving the body relative to the sea floor.

[0013] This provides the advantage of improving fine control of the position of the apparatus, thereby minimising the risk of damage to drilling or coring installations.

[0014] The moving means may comprise at least one track.

[0015] At least part of said moving means may be adjustable in position in a direction transverse to a direction of movement of the support apparatus.

[0016] This provides the advantage of enabling the dimensions of the support apparatus to be minimised to enable it to pass through an aperture in a vessel at a sea surface.

[0017] At least one said track may be adjustable in position relative to said body.

[0018] According to another aspect of the present invention, there is provided a driving apparatus for driving a plurality of elongate members into a sea floor, the driving apparatus comprising:-

a support apparatus as defined above; and

drive means for driving a plurality of elongate members into the sea floor and supported by said support means such that a position of said drive means relative to said body is adjustable.

[0019] The drive means may be pivotable about at least one axis relative to said body.

[0020] At least one said axis may be substantially parallel to a direction of travel of the driving apparatus.

[0021] At least one said axis may be transverse to a direction of travel of said driving apparatus.

[0022] The drive means may comprise drilling apparatus.

[0023] The drive means may comprise coring apparatus.

[0024] A preferred embodiment of the present invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which:-

Figure 1 is a side view of a driving apparatus embodying the present invention with a drill tower thereof in a raised position;

Figure 2 is a side view of the driving apparatus of Figure 1 with the drill tower thereof in a lowered position;

Figure 3 is a side view of an arrangement comprising the driving apparatus of Figure 1 with the drill tower thereof engaging a well control module in a drilling operation;

Figure 4 is a front view of the arrangement of Figure 3;

Figure 5 is a top view of the arrangement of Figure 3; and

Figure 6 is a detailed view of part of the arrangement of Figure 4;

Figure 7 is a side view of part of the apparatus of Figure 1 showing details of a pipe feeding mechanism; and

Figure 8 is a plan view of the pipe feeding mechanism of Figure 7.

[0025] Referring to Figure 1, a driving apparatus 2 for driving elongate members in the form of hollow pipes 4 into the seabed as part of a drilling or coring operation has a body 6 supported on moving means in the form of a pair of tracks 8 mounted around axles 10 and controlled by hydraulic power units 12 (Figure 5). As shown in greater detail in Figures 4 and 6, the tracks 8 are moveable on the axles 10 relative to the body 6 between respective extended positions 12 and retracted positions 14.

[0026] A drill tower 16 having a drill motor 18 is supported by support means in the form of support arms 20 such that the position of the drill tower 16 is adjustable relative to the body 6. This enables the drill tower 16 to be located on top of a well control module 38 (Figure 3) or blow out preventer in the case of drilling operations, or directly on the sea bed (Figure 2) in the case of coring operations. The drill tower 16 is also pivotable about an axis 22 (Figure 5) generally parallel to a direction of travel of the driving apparatus 2.

[0027] The pipes 4 are arranged in locating means in the form of cassettes 24 supported on the body 6, and the body 6 has a frame 26 supporting a detachable lift point 28 located generally above the centre of gravity of the driving apparatus 2 for enabling deployment of the driving apparatus 2 from a vessel (not shown) located at the sea surface. The frame 26 defines an aperture 30 (Figure 4) for enabling the cassettes 24 to be fed through the aperture 30 by a cassette feeding mechanism (not shown) from a position 32 at a rear of the body 6 to a position 34 at the front of the body 6. Feeding means in the form of a pipe feeding mechanism 40 (Figures 7 and 8) feeds individual pipes 4 laterally into the drill tower 16. Manipulator means in the form of a manipulator arm 36 unloads empty pipe cassettes 24 from the body 6 and arranges the cassettes 24 on a suitable support (not shown) on the seabed adjacent the body 6 which limits the extent to which the empty cassettes 24 become embedded in the sea bed prior to subsequent removal. The drill motor 18 of the drill tower 16 sequentially drives the pipes 4 into the seabed through well control module 38 (Figure 3) or blow out preventer in the case of drilling operations, or directly into the sea bed (Figure 2) in the case of coring operations. Operation of the driving apparatus 2 is controlled from the vessel (not shown) at the sea surface by means of an umbilical cable (not shown).

[0028] Referring to Figures 7 and 8, the pipe feeding mechanism 40 includes a pair of cassette unload arms 42 for retracting a pipe 4 from a cassette 24 at position 34 and rotating through generally 180 degrees about pivot axis 44, and releasing the pipe 4 to a drill tower loading arm 46 for feeding the pipe 4 into the drill tower 16.

[0029] The deployment, operation and recovery of the driving apparatus 2 will now be described.

[0030] In order to deploy the driving apparatus 2 from the surface vessel to the seabed, the tracks 8 of the driving apparatus 2 are initially withdrawn to their retracted positions 14 as shown in Figure 6 to minimise the width of the driving apparatus 2. At the same time, the drill tower 16 is in its raised position as shown in Figure 1, in order to minimise the length of the apparatus 2, thereby minimising the dimensions of the aperture (known as a moon pool) on the surface vessel necessary for deploying the driving apparatus 2 through sea ice to the seabed.

[0031] The driving apparatus 2 is then lowered, by means of a support cable (not shown) attached to the lift point 28, to the seabed where it is located a sufficient distance from the well control module 38 to minimise the risk of damage to the well control module 38 as a result of movement of the drive apparatus 2 while it is being lowered to the seabed. Before the tracks 8 of the driving apparatus 2 come into contact with the seabed, they are moved outwardly of the body 6 by means of the hydraulic power units 12 to their extended positions 12 as shown in Figure 4 and the driving apparatus 2 is then moved by means of its tracks 8 to a position adjacent the well control module 38. The drill tower 16 is then lowered into engagement with the well control module 38 by means of the manipulator arm 36.

[0032] When the drill tower 16 has been brought into engagement with the well control module 38, individual pipes 4 are removed from the cassette 24 in the front position 34 by means of the pipe feeding mechanism 40 and fed sequentially and laterally into the drill tower 16. The hydraulic power units 12 drive the drill motor 18, which urges the pipes 4 downwards through the well control module 38 or directly into the sea bed. Pipes 4 are sequentially driven into the seabed in this manner until the cassette 24 in the front position 34 is emptied, and the manipulator arm 36 then unloads the empty cassette 24 from the body 6 and arranges it on a suitable support (not shown) on the seabed adjacent the body 6 for subsequent retrieval. The cassettes 24 are then fed forwards relative to the body 6 so that the place of the empty cassette 24 is occupied by a full cassette 24, and the process continued. The position 32 vacated by the rearmost cassette 24 can then be refilled with a full cassette 24.

[0033] When the drilling or coring operation is complete, the manipulator arm 36 replaces the empty cassettes 24 on the body 6 of the driving apparatus 2 for retrieval to the surface vessel.

[0034] It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims.

Claims

1. A support apparatus for supporting drive means for driving a plurality of elongate members into a sea floor, the support apparatus comprising:-

a body adapted to support a plurality of said elongate members;

support means provided on said body for supporting said drive means such that a position of said drive means is adjustable relative to said body;

feeding means for feeding a plurality of said elongate members to said drive means; and

control means for enabling control of said support apparatus from a vessel located at a sea surface.

2. A support apparatus according to claim 1, wherein said feeding means is adapted to (i) simultaneously feed a plurality of said elongate members, located in position relative to each other by means of locating means, with at least part of said locating means to at least one first location on said body and to (ii) sequentially feed a plurality of said elongate members from at least part of said locating means at at least one said first location to said drive means.

3. A support apparatus according to claim 2, further comprising manipulator means for unloading at least part of said locating means from said body.

4. A support apparatus according to any one of the preceding claims, further comprising at least one engaging portion for engaging lifting means to enable lifting of the support apparatus, wherein said feeding means is adapted to feed a plurality of said elongate members through at least one aperture below said engaging portion in use.

5. A support apparatus according to any one of the preceding claims, further comprising moving means for moving the body relative to the sea floor.

6. A support apparatus according to claim 5, wherein said moving means comprises at least one track.

7. A support apparatus according to claim 5 or 6, wherein at least part of said moving means is adjustable in position in a direction transverse to a direction of movement of the support apparatus.

8. A support apparatus according to claims 6 and 7, wherein at least one said track is adjustable in position relative to said body.

9. A driving apparatus for driving a plurality of elongate members into a sea floor, the driving apparatus comprising:-

a support apparatus according to any one of the preceding claims; and

drive means for driving a plurality of elongate members into the sea floor and supported by said support means such that a position of said drive means relative to said body is adjustable.

10. A driving apparatus according to claim 9, wherein said drive means is pivotable about at least one axis relative to said body.

11. A driving apparatus according to claim 10, wherein at least one said axis is substantially parallel to a direction of travel of the driving apparatus.

12. A driving apparatus according to claim 10 or 11, wherein at least one said axis is transverse to a direction of travel of said driving apparatus.

13. A driving apparatus according to any one of claims 9 to 12, wherein the drive means comprises drilling apparatus.

14. A driving apparatus according to any one of claims 9 to 12, wherein the drive means comprises coring apparatus.

Drawing