UNDERWATER DRILLING APPARATUS AND METHOD FOR CREATING A CASED BOREHOLE UNDERWATER

Abstract

The invention relates to an underwater drilling apparatus comprising a lowerable platform configured for setting down on a waterbody bottom, at least one support tube axially displaceable and rotatably mounted on the platform, at least one tubular drive arranged on the platform and configured for rotationally driving the support tube, in order to rotationally introduce the support tube into the waterbody bottom, and an in-hole drilling rig arranged in the support tube, wherein the in-hole drilling rig comprises: a rig base body, at least one clamping device for bracing and securing the in-hole drilling rig in the support tube, and a drill head which is axially displaceably and is rotatably mounted on the rig base body and can be rotationally driven by means of a drill drive. According to the invention, it is provided that, when the support tube is rotationally driven, the in-hole drilling rig is arranged in the support tube and is axially clamped thereto.

Claims

1. An underwater drilling apparatus for creating a cased borehole under water, comprising a lowerable platform configured for setting down on a waterbody bottom, at least one support tube axially displaceable and rotatably mounted on the platform, at least one tubular drive arranged on the platform and configured for rotationally driving the support tube, in order to rotationally introduce the support tube into the waterbody bottom, at least one in-hole drilling rig arranged in the support tube, wherein the in-hole drilling rig comprises: a rig base body, at least one clamping device for bracing and securing the in-hole drilling rig in the support tube, a drill drive on the rig base body, and a drill head which is axially displaceable and rotatably mounted on the rig base body and can be rotationally driven by means of the drill drive, wherein when rotationally driving the support tube, the in-hole drilling rig is arranged in the support tube and is axially clamped thereto.

2. The underwater drilling apparatus according to claim 1, wherein, in order to form the tubular drive at the platform, a collet device for clamping the support tube on its outer side is arranged to be rotatably or pivotably and axially movable, wherein a torque of the tubular drive can be transmitted to the support tube.

3. The underwater drilling apparatus according to claim 1, wherein the tubular drive is configured for transmitting a continuous rotary motion to the support tube.

4. The underwater drilling apparatus according to claim 1, wherein the tubular drive is configured for transmitting an oscillating rotary motion to the support tube.

5. The underwater drilling apparatus according to claim 1, wherein the in-hole drilling rig comprises an axial feed device with which the drill head is axially displaceable relative to the rig base body.

6. The underwater drilling apparatus according to claim 5, wherein the feed device comprises at least one hydraulic feed cylinder.

7. The underwater drilling apparatus according to claim 1, wherein at least one supply line is connected to the in-hole drilling rig at an upper portion of the rig base body.

8. The underwater drilling apparatus according to claim 1, wherein two or more support tubes are rotatably and axially displaceably mounted on the platform.

9. The underwater drilling apparatus according to claim 1, wherein at least one upper clamping device is arranged on the rig base body and at least one lower clamping device is arranged on the drill head.

10. The underwater drilling apparatus according to claim 9, wherein when the support tube is rotationally driven, the at least one lower clamping device on the drill head is radially extended and the drill head is clamped to the support tube and the at least one lower clamping device on the rig base body is radially retracted and is released from the support tube.

11. The underwater drilling apparatus according to claim 1, wherein the platform at the waterbody bottom comprises a supply device connected to an overwater supply unit via at least one main supply line, and the at least one tubular drive and the at least one in-hole drilling rig are connected to the supply device of the platform for energy supply, in particular via supply lines.

12. A method for creating a cased borehole under water with an underwater drilling apparatus according to claim 1, wherein at least one support tube is arranged on a platform of the underwater drilling apparatus, at least one in-hole drilling rig is arranged in the at least one support tube, the platform is lowered onto a waterbody bottom, the at least one support tube is rotationally driven via a tubular drive at the platform and is drilled into the waterbody bottom, prior and/or subsequent to the drilling of the support tube, the drill head of the in-hole drilling rig arranged in the support tube is rotationally driven and is drilled into the waterbody bottom to create the borehole, while the support tube is held on the platform in a rotationally fixed manner, and when the support tube is rotationally driven, the in-hole drilling rig remains in the support tube and is axially clamped thereto.

Description

[0029] The invention is further described below with reference to preferred exemplary embodiments, which are shown schematically in the accompanying drawings. The drawings show:

[0030] FIG. 1 a perspective view of an in-hole drilling rig according to the invention with the drill head retracted;

[0031] FIG. 2 a side view of the in-hole drilling rig in the state of FIG. 1;

[0032] FIG. 3 a perspective view of the in-hole drilling rig of FIGS. 1 and 2 with the drill head extended;

[0033] FIG. 4 a side view of the in-hole drilling rig in the state of FIG. 3; and

[0034] FIG. 5 a side view of a platform for forming the underwater drilling apparatus according to the invention.

[0035] In FIGS. 1 to 4, an exemplary embodiment of an in-hole drilling rig 10 for forming an underwater drilling apparatus 100 according to the invention is shown. The in-hole drilling rig 10 comprises a framework-like rig base body 12 comprising a first annular frame portion 14. On the upper side of this plate-like first frame portion 14, a drill drive 40 is arranged, which, in the illustrated exemplary embodiment, is formed by three hydraulic rotary drives 42 arranged to be uniformly distributed around a longitudinal or drilling axis of the in-hole drilling rig 10.

[0036] The clamping device 50 is attached to the lower side of the first frame portion 14, which is configured for radially bracing and fixing the in-hole drilling rig 10 relative to a wall of a support tube and/or a drill hole. In the illustrated exemplary embodiment, the annular clamping device 50 comprises six non-visible and radially directed clamping cylinders, on the outer side of which plunger-like clamping plates 52 are attached. The clamping cylinders having the clamping plates 52 are uniformly distributed around the longitudinal or drilling axis of the in-hole drilling rig 10.

[0037] An upper frame portion 15 is arranged at the upper end of the frame 12. Between the upper frame portion 15 and the first frame portion 14 therebelow, a plate-shaped ring-like intermediate portion 16 is arranged, which is connected via vertically directed connecting struts 18 on the one hand to the first frame portion 14 and on the other hand upwardly to the upper frame portion 15.

[0038] A connecting device 28 for a cable suspension of the in-hole drilling rig 10 is arranged centrally on an upper side of the upper frame portion 15, and two line feeds 29 are arranged laterally thereon. The line feeds 29 serve on the one hand for feeding a hydraulic hose line and on the other hand for feeding and holding a drilling slurry discharge line.

[0039] Further feeds for compressed air for an air lifting method as well as of electrical power and data lines as well as further supply lines may be provided.

[0040] Control components 19 may be arranged on the plate-like intermediate portion 16. Overall, the upper region of the rig base body 12 may have a modular structure with the first frame portion 14, the upper frame portion 15 and the intermediate portion 16, so that the in-hole drilling rig 10 may be adapted in a simple manner to different drill hole sizes and application areas.

[0041] Below the clamping device 50 on the first frame portion 14, the feed device 70 with hydraulic feed cylinders 72 is arranged. The feed cylinders 72 are fastened to the first frame portion 14 with their cylinder housings. By means of the extendable cylinder piston, the feed cylinders 72 on the other hand are hinged to a second annular, plate-like second frame portion 20. The annular second frame portion 20 is fastened to an outer surface of a tubular bearing sleeve 24, in which a tubular drill string 38, only partially visible in FIGS. 3 and 4, is mounted to be rotatable but axially fixed. A drill head 30 is fastened to the lower end of the drill string 38. The drill head 30 comprises a central pilot tip 32 and radially directed removal elements 34, which are configured for removing soil material. The second frame portion 20 is mounted to be axially adjustable relative to the first frame portion 14.

[0042] At an upper end region of the tubular drill string 38, a drive shaft 44 of the drill drive 40 extends into the tubular drill string 38. The drive shaft 44 comprises outer, axially extending drive strips 46, which cooperate with corresponding inner drive strips on the inner side of the tubular drill string 38 for torque transmission. Via the drive shaft 44, the drill string 38 is rotationally driven with the drill head 30 so that the latter can remove soil material.

[0043] In FIGS. 1 and 2, the in-hole drilling rig 10 is shown in a state in which the drill head 30 is axially retracted. In this state, the in-hole drilling rig 10 can be fixed in the drill hole via the clamping device 50 by radial extension of the clamping plates 52 against a support tube. Subsequently, with the drill head 30 rotating, the feed device 70 can be actuated, wherein the feed cylinders 72 extend downward. Thereby, the second frame portion 20 having the bearing sleeve 24 and the drill head 30 mounted thereon can be moved downward to cause a corresponding advance during drilling. Alternatively, the drill head 30 and/or in-hole drilling rig may be braced or fixed in place when the support tube 8 is turned in.

[0044] When a maximum extension length of the feed cylinders 72 of the feed device 70 is reached, which is shown in FIGS. 3 and 4, the bracing by the clamping device 50 can be released by retracting the clamping plates 52. The upper region of the rig base body 12 may be guided along downward by retracting the feed cylinders 72 and slackening a suspension cable fastened to the connecting device 28 until the axially retracted state according to FIGS. 1 and 2 is reached again. Now, after the rig base body 12 has been clamped again by means of the clamping device 50, a further drilling step may be carried out. Alternatively, the clamping plates 52 may be radially extended and remain fixed to the support tube 8. The support tube 8 can thus be turned into the ground and guided along. The feed cylinders 72 may be retracted during this process.

[0045] Soil material produced during drilling may be discharged through the frame 12 via the hollow drill string 38, the hollow drive shaft 44 by means of a suction pump 36 as a conveying device 35 and transported away to outside of the drill hole via a partially shown conveying line 37. The second frame portion 20 having the bearing sleeve 24 may comprise a third frame portion 27, which may be mounted to be linearly displaceable via linear guides 26 which are fixedly attached to the first frame portion 14 and directed downwards. The guides 26 may absorb torsional forces in the circumferential direction, so that the feed cylinders 72 are relieved of transverse forces.

[0046] As shown in FIG. 5, an underwater drilling apparatus 100 according to the invention comprises a lowerable platform 80 having a working stage 82, which is suspended from a cable arrangement 97 shown only in part, and which may be lowered and set down onto a waterbody bottom 5 via this cable arrangement 97 with adjustable feet 88.

[0047] As shown in FIG. 5, a plurality of support tubes 8 with in-hole drilling rigs 10 inserted therein may be arranged on the working stage 82, of which two in-hole drilling rigs 10 are visible in the side view in FIG. 5. Four in-hole drilling rigs 10 may be arranged at the corners of the working stage 82, which is configured as a geometric rectangle, or three in-hole drilling rigs 10 may be arranged at the corners of the working stage, which is configured as an equilateral triangle.

[0048] The in-hole drilling rigs 10 are formed substantially equal so as this is previously described.

[0049] The in-hole drilling rig 10 serves for introducing a support tube 8 into the waterbody bottom 5. A sleeve-like linear guide 84 and a tubular drive 85 for each in-hole drilling rig 10 or each drill hole are arranged on the working stage 82. The linear guide 84 guides the support tube 8 vertically displaceable on the working stage 2. The drilling unit 100 further comprises, for forming the tubular drive 85, a collet device 86 for securing in a rotationally fixed manner, rotating and/or axially displacing the support tube 8 on the working stage 82. This collet device 86 is arranged below the linear guide 84 on the working stage 82. The collet device 86 may be configured, for example, as a hydraulic clamping device and also comprises means for axially securing the support tube 8, i. e. means for securing it against displacement in the vertical direction. The collet device 86 may thus ensure that, for example, the support tube 8 maintains its rotational position but also its axial position relative to the working stage 82 during lowering of the working stage 82, but also during the drilling operation.

[0050] In order to produce a borehole into which the support tube 8 is introduced, the in-hole drilling rig 10 is inserted thereinto. At the lower end of the in-hole drilling rig 10, a drill head 30 configured as a full-face drill head or another suitable drill head which is equipped with roller bits, may be provided. The drill head 30 may protrude at the lower end of the support tube 8, so that the drill head 30 can clear soil material below the support tube 8. The support tube 8 may be pushed axially following the in-hole drilling rig 10 in a rotating manner via the collet device 86. When the support tube 8 is displaced, the in-hole drilling rig 10 may be braced in the support tube 8 and thus guided along with it. An energy supply may be provided via a main supply line 92 to a central supply device 90 on the working stage 82.