WO2013109147A2

WO2013109147A2 - Displaceable drilling rig comprising a drilling tower

Info

Publication number: WO2013109147A2
Application number: PCT/NL2013/050026
Authority: WO
Inventors: Arthur Alexander DE MUL; Diederick Bernardus Wijning; Joop Roodenburg
Original assignee: Itrec B.V.
Priority date: 2012-01-20
Filing date: 2013-01-18
Publication date: 2013-07-25
Also published as: WO2013109147A3

Abstract

The invention relates to a displaceable drilling rig comprising at least a drilling tower, wherein said drilling rig comprises a displacement system to displace the drilling rig with respect to a support surface in a substantially horizontal direction, wherein the displacement system comprises two or more displacement devices to displace the drilling rig, wherein each displacement device comprises: a displacement foot extendable and retractable in a substantially vertical direction between an extended position, in which the displacement foot is arranged on the support surface, and a retracted position, in which the displacement foot is free from the support surface, and wherein the displacement foot comprises a lift actuator to move the displacement foot between the retracted position and the extended position, wherein said displacement foot comprises a lower part and an upper part, wherein said lower part is configured to be placed on the support surface, and wherein said upper part is connected to the drilling rig, wherein said lower part is movable with respect to the upper part in at least one substantially horizontal direction, and wherein said displacement foot comprises one or more displacement actuators to move the lower part and the upper part with respect to each other in the at least one substantially horizontal direction.

Description

Displaceable drilling rig comprising a drilling tower Field of the invention

The present invention relates to a displaceable drilling rig comprising a drilling tower. More particularly, the invention relates to a drilling rig comprising a displacement system configured to displace the drilling rig. Further, the invention relates to a method to displace a drilling rig and a method to drill multiple drill holes in a well area.

Background of the invention Generally, there is a need for a drilling rig which can be displaced between different positions, for example a first and a second drilling location.

Skid systems are known to provide for such displacement. US 6,554,075 discloses such skid system. The drilling tower is arranged on skid elements which can be moved over a first set of two skid beams arranged in parallel in a first horizontal direction. The skid beams are placed on a second set of skid beams arranged in parallel in a second horizontal direction substantially perpendicular to the first horizontal direction.

The drilling tower can be displaced with respect to the first and second set of skid beams by sliding the skid elements over the first set of skid beams and/or by sliding the first set of skid beams over the second set of skid beams. The force required to make these sliding movements may be provided by one or more hydraulic actuators which push or pull the drilling tower over the first set of skid beams and/or the first set of skid beams over the second set of skid beams.

To use the skid system, the first set of skid beams and the second set of skid beams have to be arranged in a horizontal position. This may be time-consuming. Moreover, the actuators have to be properly aligned with the skid beams to make sure that the skid movements are carried out correctly.

Furthermore, the range of movement of the drill tower is limited by the length of the first and second set skid beams. The range of movement may be increased by increasing the length of the first and second set of ski beams. However, it may be very challenging to properly position and align the skid beams over a longer length.

A general object of the present invention is to provide a new and improved drilling rig that is easy to move and set up.

An object of the present invention is to provide a new and improved drilling rig and methods which allow to displace a drilling rig comprising at least a drilling tower over a support surface, for example from one drilling location to another drilling location.

A further object of the invention it provide a new and improved drilling rig which can be displaced over a support surface over relative long distances and in a reliable, quick and efficient manner.

Summary of invention

The invention provides a displaceable drilling rig comprising a drilling tower,

wherein said drilling rig comprises a displacement system to displace the drilling rig with respect to a support surface in a substantially horizontal direction, wherein the displacement system comprises two or more displacement devices to displace the drilling rig, wherein each displacement device comprises:

a displacement foot extendable and retractable in a substantially vertical direction between an extended position, in which the displacement foot is arranged on the support surface, and a retracted position, in which the displacement foot is free from the support surface, and wherein the displacement foot comprises a lift actuator to move the displacement foot between the retracted position and the extended position,

wherein said displacement foot comprises a lower part and an upper part, wherein said lower part is configured to be placed on the support surface, and wherein said upper part is connected to the drilling rig,

wherein said lower part is movable with respect to the upper part in at least one substantially horizontal direction, and wherein said displacement foot comprises one or more

displacement actuators to move the lower part and the upper part with respect to each other in the at least one substantially horizontal direction.

The drilling rig is a combination of parts of a drilling system connected to each other as a single rigid body. The drilling rig comprises at least a drilling tower. The displacement system makes it possible to displace the drilling rig and other parts of the drilling system rigidly connected to the drilling rig, without the need to disassemble the different parts of the drilling rig. During displacement of the drilling system, the drilling tower may be in the operational position, in which the drilling tower may extend in a substantially vertical direction.

The drilling rig comprises two or more displacement devices to displace the drilling rig over the support surface. Other devices may be provided to cooperate with the two or more displacement devices to displace the drilling rig. In practice, three or four displacement devices may be provided to support and displace the drilling rig.

The displacement foot is extendable and retractable in a substantially vertical direction between an extended position, in which the displacement foot is arranged on the support surface and supports the drilling rig, and a retracted position, in which the displacement foot is free from the support surface and the drilling rig is supported by other support means, for example support feet of the drilling rig. The other support means may also be formed by other displacement feet of the two or more displacement devices.

In an embodiment, the lift actuators of the two or more displacement devices together are capable to provide sufficient lifting force to lift the complete drilling rig, and the one or more displacement actuators of the two or more displacement devices are capable to provide sufficient force to move the complete drilling rig in the substantially horizontal direction. In such embodiment no further lifting or displacement means are required to lift and displace the drilling rig over the support surface. When the displacement foot is in the extended position, the drilling rig can be displaced by relative movement in the horizontal direction of the upper part with respect to the lower part. This movement can be relatively small. In the retracted position, the displacement foot is no longer arranged on the support surface and the lower part and the upper part can be brought back in their initial relative position without movement of the drilling rig with respect to the support surface. By repeating these horizontal relative movements of the upper part and lower part in the extended and retracted position of the displacement feet, the drilling rig can be moved step-wise over the support surface.

The distance that can be travelled with the displacement system is in principle unlimited. Only the support surface should be suitable to support the drilling rig. Rig mats or other support means may be placed on the earth to form a suitable support surface.

In another embodiment, the support surface may be formed by the ground. The support surface may also be an offshore platform or deck. The upper part of the displacement foot is connected to the remaining parts of the drilling rig to transfer the load of the drilling rig to the support surface, when the displacement foot is in the extended position.

In an embodiment, the drilling rig comprises a support frame and the upper part of the displacement foot is connected to the support frame to support the drilling rig. The support frame may be any object arranged between the drilling rig and the displacement foot constructed to transfer the gravity force from the drilling rig to the displacement foot. The support frame may be mounted on the displacement foot or on any other part of the drilling rig.

In an embodiment, the displacement device is part of a modular support and displacement device. In addition to a displacement device to displace the drilling rig, it also advantageous to have a number of support locations which provide for support to the drilling rig during the operation of the drilling rig. Advantageously, each of the displacement devices of the invention are integrated in a modular support and displacement device which can provide support during operation of the drilling system and is able to displace the drilling rig over the support surface. In an embodiment, the displacement foot is at least partially rotatable about its longitudinal axis to adapt the substantially horizontal direction to a desired direction of movement. It may be constructionally advantageous that the upper part and lower part can only move with respect to each other in a single horizontal direction. By rotation of at least part of the displacement foot this horizontal direction of movement may be adjusted to the desired direction of movement.

In an embodiment, the displacement foot is rotatable between two rotational positions at about 90 degrees with respect to each other. By making displacement steps in one or both of the two resulting perpendicular horizontal directions, the drilling rig can be moved to any desired location.

In an embodiment a turntable may be provided to make rotation of the displacement foot possible. Also other devices or constructions may be provided to make partially rotation of the displacement foot possible. An actuator may be provided to control the rotational position of the displacement foot. In an embodiment, the displacement device comprises a tilt adjustment device, capable of adjusting an orientation of the displacement foot to a non-horizontal support surface. The support surface on which the drilling system is supported may not be completely flat. A tilt adjustment device may be arranged in the displacement foot to adapt the orientation of the displacement foot. This tilt adjustment device may be a passive device which automatically adjusts the orientation of the displacement foot to the orientation of the support surface or an active device, which is actively controlled to adjust the position of the displacement foot to the orientation of the support surface.

In an embodiment, the upper part of the displacement foot is connected to a support frame to support the drilling rig, wherein the support frame carries one or more support feet configured to be arranged on the support surface when the displacement foot is in the retracted position and to be free from the support surface when the displacement foot is arranged in the extended position. The support feet can be used to support the drilling rig when the displacement feet are brought in the retracted position. The support feet may also be used, possibly in combination with the displacement feet, to provide support in the drilling rig during operation of the drilling rig.

In an embodiment, the one or more support feet are vertically displaceable with respect to the support frame in order to adjust a height and/or orientation of the support frame with respect to the support surface. By vertical adjustment of the support feet of the displacement system, the position and orientation of the support frames of the displacement devices can be adjusted for example to maintain the support frames of the several displacement devices in a constant relative position.

In an embodiment, an upper surface of the lower part comprises a slide surface over which the upper part can slide in the substantially horizontal direction. Sliding of the upper part over the lower part is a suitable construction to create the relative movement between the upper part and the lower part of the displacement foot, while at the same time the load of the drilling rig can be transferred between the upper part and the lower part.

In an alternative embodiment, other means may be provided to make a horizontal movement between the upper part and the lower part possible, whereby at the same time the load of the drilling rig may be transferred from the upper part to the lower part. For example one of the upper part and lower part may comprise a roller or gear wheel and the other part a surface or tooth rack over which the roller or gear wheel can roll.

In an embodiment, the displacement system comprises a control system to control the lift actuators and the one or more displacement actuators. It is desirable that the lift actuator and the one or more displacement actuators of each of the displacement devices are

simultaneously controlled so that the movements of the displacement feet on the different displacement devices, and in particular the horizontal movements of the drilling rig are carried out substantially simultaneously. A control system may be provided to control the In an embodiment, the control system may also be configured to control an actuator for adapting the rotational position of the displacement foot in order to control the direction of movement of the displacement system.

The invention further relates to a method to displace a drilling rig as claimed in claim 1 in a substantially horizontal direction, comprising the steps of:

a) lifting the drilling rig by vertically extending the displacement feet to a position such that the drilling rig is only supported by the displacement feet of the displacement devices, b) moving from an initial relative position between the upper parts and the lower parts the upper parts of the displacement feet in the substantially horizontally direction with respect to the lower parts to move the drilling rig over a substantially horizontal distance,

c) lowering the drilling rig by vertically retracting the displacement feet until the displacement feet are free from the support surface, and

d) moving the lower parts relative to the upper parts of the displacement feet back to the initial relative position, and

e) repeating steps a) to d) until the drilling rig has been moved over a desired horizontal distance.

In an embodiment, the method comprises the step of rotating the displacement feet at least partially to adapt the at least substantially horizontal direction to a desired direction of movement. The invention also relates to a method for drilling multiple drilling holes in a support surface at different drilling locations, comprising the steps of:

a) providing the drilling rig as claimed in claim 1 at a first drilling location

b) drilling a first hole at the first drilling location,

c) lifting the drilling rig by vertically extending the displacement feet to a position such that the drilling rig is only supported by the displacement feet of the displacement devices, d) moving from an initial relative position between the upper parts and the lower parts of the displacement feet, the upper parts of the displacement feet in the substantially horizontally direction with respect to the lower parts to move the drilling rig over a horizontal distance, e) lowering the drilling rig by vertically retracting the displacement feet until the displacement feet are free from the support surface, and

f) moving the lower parts relative to the upper parts of the displacement feet back to the initial relative position, and g) repeating steps c) to f) until the drilling rig has been moved to a second drilling location, and

h) drilling a second drilling hole at the second drilling location. In some applications of a drilling rig, it is desirable that a large number of drilling holes are drilled in a certain drilling area. The drilling rig of the invention is very suitable to be used in a method wherein multiple drilling locations should be drilled, for example in a drilling area for shale gas. In such drilling area a complete well pattern with multiple well pads may be drilled by the drilling rig without the need to disassemble or partly disassemble the drilling rig to transport the drilling rig between different drilling locations. The method for drilling multiple drilling holes may for instance be used for drilling multiple holes in well pads as described in co-pending US provisional patent application 61/491 ,047, the contents of which are herein incorporated by reference in its entirety. The method of the invention allows to displace the drilling rig over the complete well area both over well pads as between different well pads without the need to disassemble or partly disassemble the drilling rig.

In an embodiment, the method comprises repeating step g) and h) to move the drilling rig to further drilling locations and to drill further drilling holes at the further drilling locations. In an embodiment, the method comprises the step of rotating the displacement feet at least partially to adapt the at least substantially horizontal direction to a desired direction of movement.

Finally, the invention relates to a displacement device to displace a substantially vertically extending construction, such as a drilling tower or crane, in a substantially horizontal direction, comprising:

a displacement foot extendable and retractable in a substantially vertical direction between an extended position, in which the displacement foot is arranged on a support surface, and a retracted position, in which the displacement foot is free from the support surface, and wherein the displacement foot comprises a lift actuator to at least move the displacement foot from the retracted position towards the extended position to exert a lifting force on the construction,

wherein said displacement foot comprises a lower part and an upper part, wherein said lower part is configured to be placed on the support surface, and wherein said upper part comprises a support frame to support the construction,

wherein said lower part is movable with respect to the upper part in at least one substantially horizontal direction, and wherein said displacement foot comprises one or more displacement actuators to move the lower part and the upper part with respect to each other in the at least one substantially horizontal direction.

The invention may also be used to displace a substantially vertically extending construction, such as a drilling tower or crane. In some embodiments, multiple displacement devices, for example three or four displacement devices may be used to displace the construction.

The displacement devices may further be constructed as described herein with respect to the displacement device for a drilling rig.

Description of the drawings

Figure 1 shows a schematic top view of an embodiment of a drilling rig according to the invention;

Figure 2 shows a cross section of one of the support and displacement units of the drilling rig of Figure 1 ;

Figure 2a shows the displacement foot of Figure 2 in more detail;

Figures 3a-3d show different steps of a displacement of the drilling rig in side view;

Figures 4a-4d show different rotational positions of the displacement foot in top view;

Figures 5a-5c show different steps for adjusting the height and/or orientation of the support feet of the support and displacement unit; and

Figure 6 shows two support and displacement units in transport state.

Description of an embodiment of the invention

Figure 1 shows a top view of a displaceable drilling rig 1 according to the invention. The drilling rig 1 is composed of a number of modular components which can be transfigured between a working configuration as shown in Figure 1 and a compact transport state. In an embodiment the transportable drilling rig is a containerized drilling rig. In this embodiment the drilling tower unit and/or one or more of the other units, preferably the drilling tower units and the shared units, are containerized units, i.e. they can be transformed from a working configuration into a compact transport configuration. In the transport configuration a unit preferably has the size of an ISO freight container, preferably a 40 feet container, to facilitate transport by train or truck. Advantageously, the base of the unit is designed as part of an ISO freight container and has ISO freight container corner fittings. In an embodiment, the drilling tower units are constructed in a way similar to the drilling tower disclosed in patent publication US 7 255 180, which is incorporated herein by reference in its entirety.

In an embodiment, the drilling rig comprises a tubular handling apparatus for the drilling tower unit that is constructed in a way similar to the tubular handling apparatus disclosed in patent publication US 7 255 180, which is incorporated herein by reference in its enirety.

The drilling rig 1 comprises a drilling tower unit 2 having drilling equipment to drill a drill hole in the earth, a mud unit 3 configured to provide the drilling tower unit 2 with drilling mud, a draw works unit 4 comprising one or more winches to be used in conjunction with the drilling tower unit 1. The drilling tower unit 2, the mud unit 3, and the draw works unit 4 are connected to each other to form an integrated drilling rig.

In other embodiments, some parts of the drilling system may not form part of the drilling rig, but may be separately supported on the ground. For example, the mud unit or draw works units may be separate shared units which are used for two drilling rigs, each drilling rig having a drilling tower. In such embodiment one or both of the drilling rigs may be provided with a displacement system as described herein.

The drilling rig 1 further comprises a displacement system, comprising four support and displacement units 5. Two support and displacement units 5 are arranged at opposite sides of the drilling tower unit 2. These two support and displacement units 5 support two outrigger arms 6 which are pivotable mounted on the drilling tower unit 5.

Two further support and displacement units 5 are arranged at opposite sides of the mud unit 3 and the draw works 4. A support arm unit 7 is provided between the between the mud unit 3 and the draw works 4. The two further support and displacement units 5 support two further outrigger arms 8 extending outwards from the support arm unit 7.

The support and displacement units 5 are provided to support the drilling rig, and, when desired to displace the drilling rig 1 in a substantially horizontally direction.

Figure 2 shows a cross-section of one of the support and displacement units 5 arranged next to the drillling tower unit 1. The other support and displacement units 5 are constructed substantially the same. Figure 2a shows the displacement foot of Figure 2 in more detail; The support and displacement unit 5 comprises a displacement foot 10 extendable and retractable in a substantially vertical direction between an extended position, in which the displacement foot is arranged on the support surface 11 , and a retracted position, in which the displacement foot 10 is free from the support surface 11. In Figure 2, the displacement foot 10 is shown in the retracted position. In the shown embodiment the support surface 11 is formed by a rig mat 12. The rig mat 12 may for example have a thickness in the range of 5 - 15 cm. The support surface 11 may also be any other suitable support surface to support the support and displacement unit 5. For example, in some embodiments the support surface may be formed by the ground.

The displacement foot 1 1 comprises a hydraulic lift actuator 13 arranged vertically configured to move the displacement foot 11 between the retracted position and the extended position.

The support and displacement device 5 comprises a support frame 14 configured to support the outrigger arm 6 of the drilling tower unit 2. The support frame 14 comprises a beam structure 15 carrying a number of support feet 16, and a displacement foot housing 17. The displacement foot housing 17 comprises a cylindrical body having an outwardly extending flange. The outrigger arm 6 is provided with a cylindrical end part 6a enclosing partially the displacement foot housing 17. The cylindrical part 6a of the outrigger arm 6 is supported on the flange of the displacement foot housing 17 and connected thereto with a number of bolts.

Between the beam structure 15 and the displacement foot housing 17 an elastic element 18, for example a ring of relative elastic material is arranged to allow some tilting between the beam structure 15 and the displacement foot housing 17. To adapt the height and/or orientation of the support feet 16 to the height and/or orientation of the support surface, each support foot 16 is connected to a screw spindle 19 rotatably arranged in a screw hole in the beam structure 15. By rotating the screw spindle 19 with respect to the screw hole, the relative position of the screw spindle 19 with respect to the beam structure 15 can be changed. Nuts 20 are provided to fix the screw spindle in a relative position with respect to the beam structure 15. By adapting the relative height between the different support feet 16 and the beam structure 15, the height and/or orientation of the support frame 14 with respect to the support surface 1 1 , when the support frame 14 is supported by the support feet 16, can be adjusted. Any other system to adapt the relative height of the support feet 16 with respect to the beam structure 15 may also be applied.

When the displacement foot 10 is in the retracted position, the displacement foot 10 is free from the support surface 1 1 as the outrigger arm 6 is supported by the support feet 16 arranged on the support surface 1 1. When the displacement foot 10 is brought into the extended position, the displacement foot 10 will lift the support feet 16 from the support surface. In the latter position, the relative position of the support feet 16 with respect to the beam structure 15 can easily be adjusted by rotation of the screw spindle 17 with respect to the beam structure 15.

The displacement foot 10 comprises an upper part comprising the hydraulic lift actuator 13 and an upper slide element 23, and a lower part comprising a lower slide element 24, a foot element 29 and a turntable 30. The lower part, in the shown embodiment foot element 29, is configured to be arranged on the support surface 1 1 when the displacement foot 10 is in the extended position. The terms lower and upper are used to indicate that in this extended position of the displacement foot 10, the lower part extends at least partially below the upper part so that it can be positioned on the support surface 11. In the retracted position of the displacement foot 10 the upper part may be at the same level as the lower part or even extend below the lower part.

The hydraulic lift actuator 13 comprises a cylinder 21 and a piston 22. The cylinder 21 of the lift actuator 13 is arranged in and fixed to the displacement foot housing 17. The piston 22 of the lift actuator 13 extends downwardly. The lower end of the piston comprises an at least partially ball shaped piston end 22a which is arranged in an opening at the upper side of an upper slide element 23. The surface of the opening at the upper side of the slide element 23 is complementary to the surface of the partially ball shaped end 22. This makes a tilting and/or rotation of the upper slide element 23 with respect to the piston end 22 possible.

The upper slide element 23 is arranged on a lower slide element 24. The lower surface of the upper slide element 24 is configured to slide in a substantially horizontal direction H over an upper surface of the lower slide element 24. Two horizontally arranged hydraulic

displacement actuators 25 are provided to control relative movement of the upper slide element 23 and the lower slide element 24. Each of the two displacement actuators 25 comprises a cylinder 26 mounted on the lower slide element 24 and a piston 27 connected to the upper slide element 23. To facilitate the sliding of the upper slide element 23 and the lower slide element 24 with respect to each other low friction material may be provided on one or both of the sliding surfaces of the upper slide element 23 and the lower slide element 24. For example, a slide pad 28 having low friction properties may be arranged on the upper side of the lower slide element 24.

The lower slide element 24 is mounted on a foot element 29. The foot element 29 is configured to be placed on the support surface 1 1. The lower surface of the foot element 29 has a relative large surface area to distribute the load of the drilling rig 1 over a large surface. A turntable 30 is provided between the lower slide element 24 and the foot element 29 to make rotation of the lower slide element 24 with respect to the foot element 29 possible.

By moving the displacement actuators 25 between a retracted position and an extended position, the upper slide element 23 can be moved with respect to the lower slide element 24 in the horizontal direction H.

The support and displacement units 5 provide the possibility to displace the drilling rig 1 , as now will be explained. A control system may be provided to control the movements of the lift actuators 13 and the displacement actuators 25 in order to move the drilling rig from a first location to a second location, for example a first drilling location and a second drilling location.

The support feet 16 at the side of the drilling tower unit 2 are provided with arms 31 having a pin 32. The pin 32 is arranged in a slot 33 provided in a slot element 34 on the drilling tower unit 2. The support and displacement units 5 are connected to the drilling tower unit 3 at three connections, as for example is shown in Figure 1. A first connection is formed by the outrigger arm 6 and two further connections are formed by pins 32 and slot 33.

The connection between pin 32 and slot 33 ensures that the support and displacement unit 5 remains in a proper orientation with respect to the drilling tower unit 2, in particular when the drilling rig 1 is moved sidewards, i.e. to the left or the right in Figure 2. At the same time, the slot 33 which runs substantially vertically, allows vertical movement of the pin 32 with respect to the slot 33 which makes vertical movement of the support and displacement unit 5 with respect to the drilling tower unit 2 possible.

Any other means to provide further connections between the drilling tower unit 2 and the support and displacement units 5 may also be applied. Similar further connections are provided to make a connection between the support and displacement units 5 and the mud unit 3 and the draw works unit 4. Figures 3a-3d shows the steps for displacement of the drilling rig 1. In Figures 3a-3d a schematic side view of the support and displacement units 5 next to the drilling tower unit 2 is shown. During displacement of the drilling rig 1 normally all four support and displacement units 5, as shown in Figure 1 , will make simultaneously the same movements to displace the drilling rig 1 in the desired direction.

In Figure 3a, the displacement feet 10 are shown in an intermediate position between the retracted and extended position such that both the displacement feet 10 and the support feet 16 are arranged on the support surface 1 1. This intermediate position can be used during normal operation of the drilling rig 1 to support the drilling rig 1 in combination with the support feet 16. To displace the drilling rig 1 in the horizontal direction, the displacement feet 10 of the support and displacement units 5 may be moved to the extended position as shown in Figure 3b. In this extended position of the displacement feet 10, the drilling rig 1 is completely carried by the displacement feet 10. From the position shown in Figure 3b, the drilling rig 1 can be completely displaced with respect to the support surface 1 1 by, in this case, pushing the upper slide element 23 with respect to the lower slide element 24 in the horizontal direction. During this sliding movement of the upper slide element 23 over the lower slide element 24 the weight of the drilling rig 1 is still completely supported by the displacement feet 10.

Figure 3c shows the drilling tower unit 1 at the end of the sliding movement in the horizontal direction, i.e. after the displacement actuators 25 have been moved from the retracted position to the extended position. The drilling rig 1 has been moved in the horizontal direction over a displacement distance. This displacement distance may for example be smaller than 1 meter or even smaller than 0,5 meter, for instance about 0,3 meters.

Once the sliding movement is finished, the displacement feet 10 can be retracted to the retracted position as shown in Figure 3d. In the retracted position the drilling rig 1 is supported on the support surface 11 by the support feet 16, and the displacement foot 10 will be free from the support surface 1 1. As the displacement foot 10 is no longer placed on the support surface 1 1 , the lower slide element 24 can be moved with respect to the upper slide element 23 without this having any effect on the position on the drilling rig 1 This makes it possible to move the lower slide element 24 to the initial relative position between the upper slide element 23 and the lower slide element 24 as shown in Figure 3a, by retracting the pistons 26 of the displacement actuators 25 to the retracted position.

When the upper slide element 23 and the lower slide element 24 are in the initial relative position, the displacement feet 10 can be brought into the intermediate position as shown in Figure 3a.

However, it may be desirable to displace the drilling rig 1 over a horizontal distance larger than the displacement distance. In that case the steps described above in relation to Figures 3a-3d may be repeated until the desired distance has been travelled by the drilling rig by taking multiple steps with the displacement distance of the sliding movement. If desirable, the length of the sliding movement can be adapted to move the drilling rig 1 over a desired distance. For example, when the desired displacement is not equal to an integer multiple of the displacement distance, the length of one or more of the steps may be adapted to adjust the displaced distance to the desired distance.

Figures 4a-4d show in top view different rotational positions of the displacement foot 10. Figures 4a and 4b show the rotational position of the combination of upper slide element 23 and lower slide element 24 to move the drilling rig 1 in forward and backward direction, corresponding to direction x in Figure 1. In Figures 4c and 4d the combination of upper slide element 23 and lower slide element 24 is rotated over 90 degrees. In this rotational position the displacement foot 10 may move the drilling rig 1 in sideward direction, corresponding to direction y in Figure 1.

It is remarked that since the foot element 29 is too large to rotate in the available space between the support feet 16, the foot element 29 is maintained in the same orientation. Since a turntable 30 is provided between the lower slide element 24 and the foot element 29, the lower slide element 24 can be rotated with respect to the foot element 29. When sufficient space is available to rotate the foot element 29 together with the lower slide element 24, the foot element 29 and the lower slide element 24 may be provided as a single part without a turntable or other rotation element placed therebetween.

The rotation of the upper slide element 23 and the lower slide element 24 with respect to the lift actuator 13 and the foot element 29 can be carried out manually, or an actuator can be provided to perform this movement.

In Figures 4a and 4c the displacement actuators 25 are shown in the retracted position; the upper slide element 23 is positioned at one side of the slide pad 28. In Figures 4b and 4d the displacement actuators 25 are shown in the extended position and, as a result, the upper slide element 23 is positioned at the other side of the slide pad 28.

By repeating movements of the displacement actuators 25 from the retracted to the extended position, when the lift actuator 13 is in one of the retracted position and the extended position, and between the extended position and the retracted position, when the lift actuator 13 is in the other of the extended position and retracted position, the drilling rig 1 can be moved, in dependence of the rotational position of the combination of upper slide element 23 and the lower slide element 24, in the x-direction or y-direction.

As long as the support surface 11 is suitable for displacement of the drilling rig 1 , the drilling rig 1 can be moved over an unlimited range to any desired location.

Figures 5a-5c show the steps to adjust the position of the support frame 14 with respect to the support feet 16 in case the position of orientation of the support surface 1 1 at the locations of the support and displacement units 5 is not the same. When moving the drilling rig with respect to the support surface 1 1 the height and/or orientation of the support surface 1 1 with respect to a support and displacement unit 5 may change.

However, it is of importance that the relative position and orientation of the support and displacement units 5 remains substantially the same. Otherwise the drilling rig 1 may not properly be supported. For example, the support feet 16 of one of the displacement units 5 may not be properly positioned on the support surface 1 1 with the result that the drilling rig 1 may tilt during operation, or the drilling rig 1 may be supported in a tilted position, which may result in toppling over of the drilling tower. Figure 5a shows the drilling rig after being moved to another position, for example a new drilling location. The support and displacement unit 5 at the right side of the drawing is placed on a relative low support surface 1 1 with a small slope. As a result, the support frame 14 is located at a relative low and angled position with respect to a desired position, in this example the same height and orientation as the support and displacement device 5 at the left side of the drawing. This is undesirable as the support locations of the drilling tower unit 2 are not at the same level. Operation of the drilling tower in such skew position may be very dangerous.

To adjust the position of the support frame 14, the position of the support feet 16 may be adjusted by rotation of the screw spindles 19. Before the screw spindles 19 are rotated the support feet 16 are lifted from the ground by extending the displacement foot 5 to the extended position. It is remarked that the lower slide element 24 of the displacement foot 10 is properly aligned with the support surface 11 as the tilt adjustment of the displacement foot 10 has corrected for the sloped support surface 11.

Figure 5b shows how the support feet are lifted from the support surface 1 1 by bringing the displacement foot to the extended position. Since the support feet 16 are free from the support surface 1 1 , the spindle can easily be repositioned by rotation of the screw spindles 19. Before rotation of the screw spindles 19, the screw spindles 19 are unlocked by unscrewing the nuts and after rotation the screw spindles 19 are again fixed in their position by screwing the nuts 20 in their locking position against the beam structure 15.

The extended position of the displacement foot 1 1 is preferably selected such that when the support feet 16 are moved downwardly until they reach the support surface 11 , they are properly positioned with respect to the support frame 14. The resulting position and orientation of the support frame after repositioning of the support feet 16 is shown in Figure 5c.

In other embodiments the support feet 16 are repositioned to the desired position, while still being free from the support surface 1 1. After proper positioning of the support feet 16 the displacement foot 11 can be brought back to the position shown in Figure 5c wherein both the displacement foot 11 and the support feet 16 are arranged on the support surface 1 1 to provide support to the drilling rig during operation of the drilling system.

The support and displacement units 5 of the invention are preferably containerized units which are part of a modular drilling system which is configurable from a number of container size construction elements. Figure 6 shows how two support and displacement units 5 arranged on top of each other may have the size of a standard container of about 8 feet (about 2,44 meters) in width W and about 9 feet and 6 inches (about 2,89 meters) in height H. The support and displacement units 5 may have a length of 20 feet (about 6 meters).

1 drilling rig

2 drilling tower unit

3 mud unit

4 draw works

5 support and displacement unit

6 outrigger arm

6a cylindrical part

7 support arm unit

8 further outrigger arm

10 displacement foot

1 1 support surface

12 rig mat

13 lift actuator

14 support frame

15 beam structure

16 support foot

17 displacement foot housing

18 elastic element

9 screw spindle

20 nut

21 cylinder

22 piston

22a piston end

23 upper slide element

24 lower slide element

25 displacement actuators

26 cylinder

27 piston

28 slide pad

29 foot element

30 turntable

31 arm

32 pin

33 slot

34 slot element

Claims

1. Displaceable drilling rig comprising at least a drilling tower,

2. The drilling rig as claimed in claim 1 , wherein the displacement device is part of a modular support and displacement device.

3. The drilling rig as claimed in claim 1 or 2, wherein the displacement foot is at least partially rotatable about its longitudinal axis to adapt the substantially horizontal direction to a desired direction of movement.

4. The drilling rig as claimed in claim 3, wherein the displacement foot comprises a turntable which allows at least partially rotation of the displacement foot.

5. The drilling rig as claimed in any of the preceding claims, wherein the displacement device comprises a tilt adjustment device, capable of adjusting an orientation of the displacement foot to a non-horizontal support surface.

6. The drilling rig as claimed in any of the preceding claims, wherein the upper part of the displacement foot is connected to a support frame to support the drilling rig, wherein the support frame carries one or more support feet configured to be arranged on the support surface when the displacement foot is in the retracted position and to be free from the support surface when the displacement foot is arranged in the extended position.

7. The drilling rig as claimed in claim 6, wherein the one or more support feet are vertically displaceable with respect to the support frame in order to adjust a height and/or orientation of the support frame with respect to the support surface.

8. The drilling rig as claimed in claim 7, wherein each of the one or more support feet are mounted on the support frame with a screw spindle, wherein the position of the screw spindle with respect to the support frame can be locked by one or more nuts arranged on the screw spindle.

9. The drilling rig as claimed in any of the preceding claims, wherein an upper surface of the lower part comprises a slide surface over which the upper part can slide in the substantially horizontal direction.

10. The drilling rig as claimed in claim 9, wherein the lower part comprises a foot element and a lower slide element, wherein the lower slide element is provided with the slide surface and the foot element is configured to be placed on the support surface, wherein a turntable is provided between the foot element and the lower slide element to allow rotation there between.

1 1. The drilling rig as claimed in any of the preceding claims, wherein the upper part of the displacement foot comprises the lift actuator.

12. The drilling rig as claimed in any of the preceding claims, wherein the upper part is connected to a support frame to support the drilling rig, and wherein the upper part comprises a first part and a second part, wherein the first part is connected to the support frame and comprises the lift actuator and an at least partially ball shaped end and wherein the one or more displacement actuators are arranged between the second part and the lower part and wherein the second part comprises a bearing surface to support the at least partially ball shaped end.

13. The drilling rig as claimed in claim 12, wherein an upper surface of the lower part comprises a slide pad and wherein the second part comprises a slide surface configured to slide over the slide pad in the substantially horizontal direction.

14. The drilling rig as claimed in claim 13, wherein the one or more displacement actuators comprise two hydraulic actuators arranged in parallel at opposite sides of the slide pad and each comprising a cylinder and a piston, and wherein the cylinders are mounted on the lower part and the pistons are connected to the second part

15. The drilling rig as claimed in any of the preceding claims, wherein the linear actuator and the one or more displacement actuators are hydraulic actuators.

16. The drilling rig as claimed in any of the preceding claims, wherein the lift actuators of the two or more displacement devices together are capable to provide sufficient lifting force to lift the complete drilling rig, and wherein the one or more displacement actuators of the two or more displacement devices are capable to provide sufficient force to move the complete drilling rig in the substantially horizontal direction.

17. The drilling rig as claimed in any of the preceding claims, wherein the displacement system comprises four modular support and displacement devices.

18. The drilling rig as claimed in any of the preceding claims, wherein the displacement system comprises a control system to control the lift actuators and the displacement actuators.

19. The drilling rig as claimed in any of the preceding claims, further comprising a mud unit, a power unit, a control unit, and/or a draw works unit.

20. A method to displace a drilling rig as claimed in claim 1 in a substantially horizontal direction, comprising the steps of:

d) moving the lower parts relative to the upper parts of the displacement feet back to the initial relative position, and e) repeating steps a) to d) until the drilling rig has been moved over a desired horizontal distance.

21. The method of claim 20, comprising the step of:

- rotating the displacement feet at least partially to adapt the at least substantially horizontal direction to a desired direction of movement.

22. Method for drilling multiple drilling holes in a support surface at different drilling locations, comprising the steps of:

b) drilling a first hole at the first drilling location,

f) moving the lower parts relative to the upper parts of the displacement feet back to the initial relative position, and

g) repeating steps c) to f) until the drilling rig has been moved to a second drilling location, and

h) drilling a second drilling hole at the second drilling location.

23. The method of claim 22, comprising repeating step g) and h) to move the drilling rig to further drilling locations and to drill further drilling holes at the further drilling locations.

24. The method of claim 22 or 23, comprising the step of:

rotating the displacement feet at least partially to adapt the at least substantially horizontal direction to a desired direction of movement.

25. Displacement device to displace a substantially vertically extending construction, such as a drilling tower or crane, in a substantially horizontal direction, comprising: