EP2737154B1

EP2737154B1 - Drilling device and method for using the same

Info

Publication number: EP2737154B1
Application number: EP13781335.8A
Authority: EP
Inventors: Sigurd Kjell Haughom
Original assignee: Norhard As
Current assignee: Norhard As
Priority date: 2012-04-23
Filing date: 2013-04-23
Publication date: 2016-10-19
Anticipated expiration: 2033-04-23
Also published as: NO334472B1; NO20120473A1; EP2737154A4; EP2737154A1; WO2013162377A1

Description

The present invention concerns a drilling device. More specifically the invention concerns a drilling device with a non-rotating drill string, the device comprising a drill bit connected to the distal end of the drill string, a drilling machine fixed to the drill string and arranged to be able to rotate the drill bit, and a back rig arranged to be able to run the drill string into and out of a borehole. The invention also concerns a method for using the device.
Drill strings in accordance with prior art consist of pipe sections with threaded connections. Fluid is supplied to the drill bit through a centric bore in the drill string. In addition to transmitting torque from a drilling motor, the drill string is also to transmit axial pushing force from a pushing device, a so-called back rig, from the surface and to the drill bit. Drill strings in accordance with prior art thus should have both high rigidity and low weight. As the drill string is screwed together from pipe sections with central bores for fluid transportation, the circulation of fluid must be discontinued upon insertion of each new pipe section. This may be very unfortunate for the drilling process as cuttings may get stuck in the borehole. Connecting and disconnecting pipe sections to/from the drill string is time consuming, and further requires expensive threaded connections between the pipe sections. Modern requirements for efficiency and directional control for drilling processes make more continuous processes and communication desirable.
The patent publication WO 2005/121494 A1 discloses a drilling device assigned to a non-rotating drill string assembled from pipe sections. The drill string is run into and out of a borehole by means of a back rig. A water hose is connected to the drill string to transport water therethrough to a drill bit powered by a drilling machine, while a cable for energy supply is connected to the outside of the drill string.
The patent publication WO 2011/046444 A1 discloses a drilling device where a drilling machine in a borehole is added drilling fluid, power and control signals through flexible lines or cables respectively, where the lines and cables may be coiled up on reels outside of the borehole.
The patent publication US 3301581 A discloses a drilling device, where a rotating drill string is assembled from pipe sections connected by means of bolt connections.
US 2677535 A discloses mine roof support beam with a wall drilling end, wherein the beam has an H shaped cross section.
The invention has for its object to remedy or reduce at least one of the drawbacks of prior art, or at least to provide a useful alternative to prior art.
The object is obtained by features given in the description below and in the subsequent patent claims.
In a first aspect, the invention concerns a drilling device with a non-rotating drill string, the device comprising:

a drill bit connected to the distal end of the drill string;
a drilling machine fixed to the drill string and arranged to be able to rotate the drill bit; and
a back rig arranged to be able to lead the drill string into and out of a borehole, characterized in the device further comprising;
a water hose arranged to be able to be run from outside and into the borehole together with the drill string along substantially the complete length of the drill string; and
a power- and signal-cable arranged to be able to be run from the outside and into the borehole together with the drill string.

In one embodiment, the drill string may be composed of steel sections. This may be standardized, commercially available steel profiles of per se known types, as for instance H-beams. Thus, drill strings may be provided without having to thread together pipe sections with centric bores. Drill strings with a non-circular section, may thus be provided, which will make possible a very effective and inexpensive connection of pipe sections.
In one embodiment, the steel sections may be connected by means of bolt connections. The bolt connections may be of per se known types.
The water hose may be wound up on a reel on the outside of the borehole. Thus a continuous water hose may easily be run into the borehole together with the drill string, without having to interrupt the water circulation upon insertion of new drill string sections to the drill string.
Furthermore, the cable for transferring power and/or communication to the drilling machines may also be wound up on a reel on the outside of the borehole. The two different reels may be arranged on opposite sides of the drill string.
In one embodiment, the device may comprise a locking device for fixing the drill string on insertion of new drill string sections to the drill string. This can be appropriate in order to ensure proper connection between subsequent drill string sections. The locking device may comprise a latch pawl connected to a hydraulic cylinder an arranged to be able to engage with holes or recesses in the drill string in order to keep it fixed.
The drill string may be provided with knobs for centring the drill string in the borehole. This may be especially appropriate for drill strings provided with a non-circular section centrally placed in the borehole.
In a second aspect, the invention concerns a method for drilling a borehole by means of a non-rotating drill string, the method comprising the following steps:

to rotate a drill bit connected to the distal end of the drill string, by means of a drilling machine;
to run the drill string into the borehole by means of a back rig, the method being characterized by further comprising the steps:
to run a water hose together with the drill string into the borehole from the outside along substantially the full length of the drill string; and
to run a power- and signal-cable together with the drill string into the borehole from the outside.

The method may further comprise to assemble the drill string by means of steel sections such as H-beams. The steel sections may, as mentioned above, be connected by means of bolt connections of per se known type.
One embodiment may further comprise to wind up the water hose on a reel on the outside of the borehole, and correspondingly wind up the cable for transferring power and signals on another reel, the two reels possibly being arranged on opposite sides of the drill string.
Use of an H-beam as a drill string section in the drill string on drilling of a borehole, is also described.
In the following an example of a preferred embodiment, which is illustrated in the accompanying drawing, is described, where:

Fig. 1: is a perspective view of a drilling device in accordance with the present invention;
Fig. 2: is a perspective view, and shown in a larger scale than in Figure 1, of details of the device in Figure 1;
Fig. 3: is a perspective view, and shown in a larger scale than in Figure 1, of further details of the device in Figure 1;
Fig. 4: is a perspective view, and shown in a larger scale than in Figure 1, of further details of the device in Figure 1; and
Fig. 5: is a perspective view, and shown in a larger scale than in Figure 1, of details of the device in Figure 1.

In the following, the reference numeral 1 indicates a rock formation in which a borehole 10 is being drilled by means of a drill bit 2 connected to the distal end of a drill string 8. A drilling machine 3, connected to the drill string 8, is arranged to be able to rotate the drill bit 2 in the borehole 10. The drill string 8 is in the embodiment shown formed by connected H-beam sections. Axial force to the drill bit 2, in a direction 26 indicated by an arrow in Figure 1, is transmitted from a back rig 28 outside of the borehole 10 via the drill string 8. The better view of the back rig is in Figure 5.
With reference to the figures 2 and 5, it can be seen that the back rig 28 is built up by steel structures 12, where the one end of the steel structures 12 is provided with an adapter 13 arranged to be able to be moved back and forth in a direction 29. The adapter 13 is provided with sliding plates 27 slidingly abutting the steel structures 12. The movement of the adapter 13 along the steel structures 12 is provided by a hydraulic cylinder 20 connected to the steel structures 12 spaced from the adapter 13.
The device also comprises a locking device 11 arranged to be able to keep the drill string 8 in a fixed position while new drill string sections are connected to the drill string 8, for example by means of bolt connections 19 as shown in detail in Figure 3. The locking device 11 comprises an outer steel structure 30 wherein a latching pawl 15 is pivotably supported around a bolt connection 16. The latching pawl is arranged to be able to be pivoted by a hydraulic cylinder 14. Furthermore, the distal end of the latching pawl 15 is provided with a locking knob 17 arranged to be able to engage with a hole 18 in the drill string 8, and thus keep the drill string 8 fixed. The locking knob 17 is withdrawn from the hole 18 to release the drill string 8.
As is best shown in Figure 4, the drill string 8 is provided with knobs 21 arranged to be able to center the drill string 8 in the borehole 10.
With reference to the Figures 2 and 4, it can be seen that a water hose 23 is wound up on a reel 4, while a power- and control-cable 24 is wound up on a reel 5. The reels 4, 5 are arranged on opposite sides of the drill string 8, below the locking device 11. The water hose 23 and the power- and control-cable 24 may thus be placed protected into a groove in the drill string 8. On the embodiment shown, the grooves are the natural, axially running recesses of the H-beam. Water, power and communication may thus be continuously transmitted to the drill bit 2 and the drilling machine 3, also on fastening of new drill string sections to the drill string 8. The water hose 23 and the power- and control-cable 24 may be connected to the drill string 8 by means of per se known connecting means.
As is best shown in Figure 4, the drill string 8 is provided with knobs 21 arranged to be able to center the drill string 8 in the borehole 10.
With reference to the Figures 2 and 4, it can be seen that a water hose 23 is wound up on a reel 4, while a power- and control-cable 24 is wound up on a reel 5. The reels 4, 5 are arranged on opposite sides of the drill string 8, below the locking device 11. The water hose 23 and the power- and control-cable 24 may thus be placed protected into a groove in the drill string 8. On the embodiment shown, the grooves are the natural, axially running recesses of the H-beam. Water, power and communication may thus be continuously transmitted to the drill bit 2 and the drilling machine 3, also on fastening of new drill string sections to the drill string 8. The water hose 23 and the power- and control-cable 24 may be connected to the drill string 8 by means of per se known connecting means.

Claims

A drilling device with a non-rotating drill string (8), the device comprising:
- a drill bit (2) connected to the distal end of the drill string (8);

- a drilling machine (3) fixed to the drill string (8) and arranged to be able to rotate the drill bit (2); and

- a back rig (28) arranged to be able to lead the drill string (8) into and out of a borehole (10), characterized in the device further comprising;

- a water hose (23) arranged to be able to be run from outside and into the borehole (10) together with the drill string (8) along substantially the complete length of the drill string (8); and

- a power- and signal-cable (24) arranged to be able to be run from outside and into the borehole (10) together with the drill string (8).
The device in accordance with claim 1, the drill string (8) being composed by steel sections shaped as H-beams.
The device in accordance with claim 2, where the steel sections are assembled by means of bolt connections.
The device in accordance with any one of the preceding claims, where the water hose (23) is supported by a reel (4) on the outside of the borehole (10).
The device in accordance with any one of the preceding claims, where the power- and signal-cable (24) is supported by a reel (5) on the outside of the borehole (10).
The device in accordance with any one of the preceding claims, the device comprising a locking device (11) for fixing the drill string (8) while inserting new drill string sections to the drill string (8).
The device in accordance with claim 6, the locking device (11) comprising a latch pawl (15) connected to a hydraulic cylinder (14).
The device in accordance with any one of the preceding claims, where the drill string (8) is provided with knobs (21) for centering of the drill string (8) in the borehole (10).
A method for drilling a borehole (10) by means of a non-rotating drill string (8), the method comprising the following steps:
- to rotate a drill bit (2) connected to the distal end of the drill string (8), by means of a drilling machine (3);

- to run the drill string (8) into the borehole (10) by means of a back rig (28), characterized by the method further comprising the steps:

- to run a water hose (23) together with the drill string (8) into the borehole (10) from the outside along substantially the full length of the drill string (8); and

- to run a power- and signal-cable together with the drill string (8) into the borehole (10) from the outside.
The method in accordance with claim 9, the method further comprising to assemble the drill string by means of steel sections like H-beams.
The method in accordance with claim 10, the method further comprising to assemble the steel sections by means of bolt connections.
The method in accordance with claim 9, 10 or 11, the method further comprising to wind up the water hose (23) and the power- and signal-cable (24) on reels (4, 5) outside of the borehole (10).
The method in accordance with any one of the claims 8-12, the method further comprising to fix the drill string (8) by means of a locking device (11) while inserting new sections to the drill string (8).
The method in accordance with any one of claims 8-14, the method further comprising to center the drill string (8) in the borehole (10) by means of knobs (21).