Jack-up, movable drilling platforms are employed for offshore oil and gas drilling, and may also be used in drilling injection wells. This type of platform has pontons and a substructure in the form of collapsible legs. The platforms normally have a main deck where the drilling rig is located, and often also include an accommodation module, hoisting cranes, a helicopter deck and necessary processing equipment for handling oil and gas which flows out of the well during drilling.

During operation the platform is moved to a drilling field where the legs are unfolded, or more correctly, the platform is jacked up along the legs. One or more wells are then drilled with the drilling rig. If several wells are drille, which is usually the case, the drilling rig is pushed or pulled into a new position on the main deck for drilling a new well. This makes it possible to drill several wells without moving the platform, but the number of positions for drilling wells is naturally limited by the size of the main deck. If more wells require to be drille, the platform has to be moved, which is a time- consuming and costly operation.

Since it is often desirable to drill more wells than is possible without moving the drilling platform, there is consequently a need for a drilling platform on which it is possible to drill more wells than from the known drilling platforms.

The object of the invention is to provide a jack-up, movable drilling platform where the drilling rig can be moved to a greater number of positions for drilling than is the case on known jack-up, movable drilling platforms.

The object is achieved according to the invention with a jack-up, movable drilling platform of the type mentioned in the introduction which is characterized by the features which are indicated in the claims.

The invention will now be explained in more detail in connection with a description of a specific embodiment, and with reference to the drawings, in which:

1g. 1 is an elevational view of a drilling platform according to the invention where an outrigger structure is located in a retracted position.

Fig. 2 is a top view of the drilling platform in fig. 1.

Fig. 3 is an elevational view of a drilling platform according to the invention where the outrigger structure is located in an extended position.

Fig. 4 is a top view of the drilling platform in fig. 3.

Fig. 5 illustrates a rail with a gripping notch for use in the invention.

Fig. 6 illustrates a jack for use in the invention.

Fig. 7 is a top view of a preferred embodiment of a drilling platform according to the invention with the outrigger structure in an extended position.

Fig. 8 is a translucent view of a part of the outrigger structure.

Fig. 9 is a cross section taken along intersecting line IX-IX in fig. 8.

Fig. 10 is a cross section taken along intersecting line X-X in fig. 8.

Fig. 11 is a cross section taken along intersecting line XI-XI in fig. 8.

Fig. 12 shows a detail of a guide in fig. 9.

Fig. 13 shows a detail of a guide in fig. 10.

Fig. 14 shows a detail of a guide in fig. 11.

Fig. 15 shows a guide viewed from above.

Figs. 1 and 2 are elevational view and a top view respectively of a jack-up, movable drilling platform according to the invention, comprising a deck 1, a drilling rig 2 and a substructure 3 in the form of three legs. By means of the drilling rig 2 wells can be drilled in the known manner for recovery of oil and gas or injection of gas or water. The drilling platform further comprises hoisting cranes 12, a helicopter deck 13, an accommodation module 14 and pontons 15. In addition the drilling platform inclues necessary not shown processing equipment for handling oil and gas which flows out of the well during drilling. The drilling rig 2 is located on and secured to an external portion of a telescopic outrigger structure 4, which in figs. 1 and 2 is shown

in a retracted position where the drilling rig 2 is located above or inside the deck 1.

Figs. 3 and 4 are an elevational view and a top view respectively of the same drilling platform where the telescopic outrigger structure 4 is shown in an extended position, and the drilling rig 2 is located outside the deck. The drilling rig 2 can thereby drill wells from a position which is located outside the deck 1, with the result that more wells can be drilled than if the drilling rig 2 had only been able to be moved within the confines of the deck 1.

The outrigger structure 4 consists of an inner arm 5 which is movably attache to the deck 1 for movement in a direction P 1, see figes. 3 and 4. In figes. 1 and 2, where the outrigger structure 4 is located in its retracted position, the inner arm 5 is located entirely above or inside the deck 1. In the outrigger structure's extended position illustrated in figes. 3 and 4 the inner arm 5 is located partly inside the deck 1, and partly outside, with an external portion 6 of the inner arm 5 projecting outwards and away from the deck 1.

The outrigger structure 4 further comprises an outer arm 7 which is movably attache to the inner arm 5 for movement in the same direction P 1. The outer arm 7 is movable between a retracted position illustrated in figs. 1 and 2 where, except for an external portion 8, it is located inside the inner arm 5, and an extended position illustrated in figes. 3 and 4 where it is located partly outside the inner arm 5 and projects away from the deck 1. The drilling rig 2 is securely attache to the outer arm's external portion 8, and is located in the position illustrated in figes. 1 and 2 inside the deck 1, while in the position illustrated in figes. 3 and 4 it is located furthest away from the drilling platform.

The outrigger structure 4 also comprises a telescopically movable pipe bridge 9 for transferring drill pipes and casings between the deck 1 and the drilling rig 2. The telescopic retraction and extension of the pipe bridge 9 accompanies the telescopic retraction and extension of the outrigger structure 4, in the direction P I. The pipe bridge 9 is thus shown in its retracted position in figs. 1 and 2, and in its extended position in figes. 3 and 4. The pipe bridge is located on top of the outrigger structure 4 and securely attache thereto, and apart from its telescopic construction is of a known type.

The outrigger structure 4 also inclues a telescopically movable gangway 10 for connection between the deck 1 and the drilling rig 2. The telescopic retraction and extension of the gangway 10 also accompanies the telescopic retraction and extension of the outrigger structure 4 in the direction P 1, and the gangway's retracted and extended positions consequently also conform with the corresponding positions of the outrigger structure. The gangway 10 is located on top of the outrigger structure 4 and is securely attache thereto.

In the illustrated embodiment the pipe bridge 9 and the gangway 10 are designed as a joint unit, but they may also be separate.

In connection with the pipe bridge and the gangway there are also illustrated guide rails 16, which will be described in more detail in connection with fig.

7.

Fig. 4 also illustrates two rails 28 in the deck 1, arrange in extension of the inner arm 5. The rail 28 is shown in closer detail in fig. 5, where it shows how it inclues gripping notches 17 for co-operation with jack attachment points.

Fig. 6 illustrates a jack 27. The jack is attache to the inner arm 5 at a jack point 32, and by means of a second jack point 33 grips the gripping notches 17. By alternately jacking up and moving the jack point 33 along the rail 28, an intermittent shifting of the inner arm 5 relative to the deck 1 is achieved.

By means of not shown corresponding jacks and gripping grooves an intermittent shifting of the outer arm 7 relative to the inner arm 5 is achieved.

Fig. 7 illustrates how the external portion 8 of the outer arm 7 comprises a rail system 11 for moving the drilling rig 2 in a direction P2 perpendicular to the inner arm's and the outer arm's direction of movement P 1. In comparison with an embodiment where the drilling rig is only movable in the direction P1, the avantage is achieved that the drilling rig 2 can be located in several positions, thereby making it possible to drill several wells without moving the drilling platform. By means of guide rails 16 the pipe bridge 9 is dispose movably in the direction P2 perpendicular to the inner arm's and the outer arm's direction of movement P1, thus enabling the pipe bridge 9 to accompany the drilling rig 2 as it moves in the direction P2 along the rail system 11. By means of the same guide rails 16 the gangway 10 is also dispose movably in the direction P2 perpendicular to the inner arm's and the

outer arm's direction of movement P1, thus enabling the gangway 10 to also accompany the drilling rig 8 as it moves along the rail system 11.

Fig. 8 is a translucent view of a part of the outrigger structure 4. This shows how the outer arm 7 comprises two beams which are provided partly inside two beams which form part of the inner arm 5. Fig. 8 illustrates the principle design of the outrigger structure 4, and thus guides for the beams, which will be discussed below, are not shown in fig. 8.

Figs. 9,10 and 11 are cross sections through the beams which form part of the inner arm 5 and the outer arm 7, viewed along intersecting lines IX-IX, X-X and XI-XI respectively in fig. 8. These figures illustrate how the beams which form part of the inner arm 5 have an open, box-shaped cross section with a lower flange 35, while the beam which forms part of the outer arm 7 has an I-shaped cross section.

Fig. 9 illustrates lateral guides 20 which are attache to the deck and abut against the flange 35 on the beam which forms part of the inner arm 5, thus providing this beam with lateral support. It further illustrates how the lower edge of this beam is supporte by lower vertical guides 23 which absorb downwardly directe forces. The beam which forms part of the outer arm 7 is laterally supporte by lateral guides 25, and at the lower edge by vertical guides 24, both the lateral guides 25 and the vertical guides 24 being provided inside the beam which forms part of the inner arm 5.

Fig. 10 illustrates how the beam which forms part of the inner arm 5 in section X-X is supporte by upper vertical guides 21, which absorb upwardly directe forces. The lower vertical guides 23 for the beam which forms part of the inner arm 5 and the lateral guides 25 and the vertical guides 24 for the beam which forms part of the outer arm 7 are of the same type as in fig. 9.

Fig. 11 shows combine lateral guides and locks 22, which, apart from having the same function as the lateral guides 20, can also secure the beam which forms part of the inner arm 5, thus enabling the inner arm 5 to be locked in the desired position.

Fig. 12 shows the lateral guide 20 and the lower vertical guide 23 in closer detail, and illustrates how the lateral guide 20 and the lower vertical guide 23

are located with contact faces 36 and 34 respectively abutting against corresponding contact faces 37 and 38 respectively on the flange 35.

Fig. 13 shows the upper vertical guide 21 in fig. 10 in closer detail, and illustrates how it is located with a contact face 40 abutting against a corresponding contact face 39 on the flange 35. The lower vertical guide 23 is of the same type as illustrated in fig. 12.

Fig. 14 illustrates a detail of the combine lateral guide and lock 22 in fig.

11. It shows how it comprises a lock shoe 29, which may be hydraulically operated, and which abuts against the contact face 37 on the flange 11, holding it securely.

Fig. 15 shows a guide 20 viewed from above. It illustrates how this is provided with outwardly facing angled end sections 26, thus forming angled surfaces which, when the beam which forms part of the inner arm 5 is moved outwards or inwards on the deck 1, will guide end portions 30 of the flange 35 into position against the guide 20, thus guiding the inner arm 5 in the direction P I.

The beam which forms part of the outer arm 7 will be provided with guides and lock shoe corresponding to those described in the above and illustrated in figs. 12-15, in order to guide and to be able to secure the outer arm 7 relative to the inner arm 5. For both the inner arm and the outer arm the guides will be placed at predetermined intervals along the longitudinal direction of the inner arm and the outer arm respectively.

In an actual embodiment of the outrigger structure 4 the extent and direction of the forces acting on the inner arm's and the outer arm's different guides will have to be determined by an analysis of the actual design, and the choice of the type of guides and their sizing in the various positions along the beams which form part of the inner arm and the outer arm will have to be selected on this basis. Thus the position of the sections IX-IX, X-X and XI-XI should be regarde as exemplifications.