WO2012038583A1

WO2012038583A1 - Method and apparatus for down-the-hole drilling

Info

Publication number: WO2012038583A1
Application number: PCT/FI2011/050587
Authority: WO
Inventors: Kai Gylling
Original assignee: Atlas Copco Rotex Oy AB
Current assignee: Tercope Finland Oy
Priority date: 2010-09-23
Filing date: 2011-06-20
Publication date: 2012-03-29
Anticipated expiration: 2013-03-23
Also published as: FI20105983A0

Abstract

The invention relates to a method and an apparatus for down-the-hole drilling, the drilling being carried out by an apparatus having a drilling device consisting of a casing part (2) and a drilling unit (3), inside thereof. The drilling unit includes; first drilling means (4) for drilling a centre hole and second drilling means (5) for reaming the centre hole for the casing (2). The first drilling means and the second drilling means (4, 5) are releasably coupled to each other. The casing part (2) is arranged to be drawn into the hole by the first and/or second drilling means (4, 5). A flushing medium is led by means of essentially radially (r) extending grooves (6a; 6a2) in the drilling surfaces (P1, P2) of both the first and the second drilling means (4, 5), to an outer periphery of the second drilling means (5), and further inside the casing (2) through an inlet opening assembly (6bx) that is placed in a longitudinal direction after the first and second drilling means (4, 5).

Description

Method and apparatus for down-the-hole drilling

The invention relates to a method and apparatus for down-the-hole drilling according to the preambles of the independent claims .

A way to carry out earth drilling in a more developed manner compared to prior art is formerly known e.g. from Finnish Patent No. 95618. A drilling head of a drilling unit of the drilling apparatus presented in this patent, existing inside a casing part or in other words in a so called casing pipe, is formed of a first frame part and an annular second frame part, in the drilling surfaces of which there has been arranged drilling organs, such as drill bits or like, of the first and second drilling means or in other words of a center drill or a pilot and a reamer. In this solution, the first drilling means that is the first frame part forming the pilot, is being released from the second frame part forming the reamer, in order to pull the same alone off from a drilled hole after the drilling situation. In the solution in question, the second organs of the flushing means for removal of drilling waste being generated are arranged to lead drilling waste by means of an assembly, which connects the said drilling means together for a drilling situation unro- tatively in respect with each other and in both directions longitudinally, which is in other words carried out as an advantageous embodiment by loosening grooves, belonging to a bayonet coupling, placed longitudinally in the outer periphery of the first frame part.

The drilling apparatus enabled by the patent mentioned above has been proven efficient and also to be easily modified according to different drilling purposes during the multiyear experience in practice. Regarding the same, however, possibilities for further improvement especially for placement and wear fatigue of the first and second drilling means' drilling organs, such as e.g. of the drill bits, have been found out, because the flushing medium and the drilling waste being generated are led straight inside the casing part from the drilling unit's drilling surface, or in other words with return flow holes and longitudinal flow ducts situated in radial direction between the pilot and the reamer. It is an aim of the method and apparatus according to the present invention to achieve a decisive improvement in the functioning of especially the type of a drilling apparatus described above and thus to raise essentially the level of prior art. In order to carry out this aim, the method and apparatus according to the invention are mainly characterized by what has been presented in the characterizing parts of the independent claims related thereto.

As the most important advantages of the method and apparatus according to the invention may be mentioned simplicity and efficiency of the constructions and operating principles enabled by the same first of all thanks to the fact that the functioning of the drilling apparatus that has already been found technically very well functionable may further be enhanced by enabling the positioning of the drilling organs, such as the drill bits, in an optimized manner also in connection with the coupling surface between the pilot and the reamer. In addition, the leading of the flushing medium on the drilling surface of the drilling means continuously in a radial direction from the import openings from the pilot's drilling surface to the reamer' s outer periphery significantly enhances the flushing of the reamer's drilling organs especially, when the flushing medium may drift to them as efficiently as to the pilot's drilling organs, which is advantageously carried out by radial guide grooves in the pilot's and reamer's drilling surfaces. Therefore, thanks to the enhanced flushing of the reamer's drilling organs, it is possible to significantly increase their drilling efficiency and operating time.

Other advantageous embodiments of the method and apparatus according to the invention have been presented in the dependent claims related thereto. In the following description the invention is illustrated in detail with reference to the appended drawings, in which, in figure 1

is shown a longitudinal cross-sectional view of one advantageous construction presenting prior art, in which the flushing medium and the drilling waste are led inside the casing part from between the first and second dril- ling means through flow ducts passing in longitudinal direction, in figure 2

is shown a longitudinal cross-sectional view of a flushing flow taking place in connection with an advantageous drilling device applying the method according to the invention, in figure 3

is shown an advantageous flushing flow principle that is an alternative or a complementing implementation with respect to the one shown in figure 2, in figures 4a and 4b

are shown a flushing flow arrangement in a front view from the point of view of the drilling unit's drilling surface presenting prior art, and as a corresponding view, a flushing flow arrangement being carried out according to the invention, and in figures 5 and 6

are shown two advantageous alternative or with respect to one another complementing extra flow arrangements being applied in the invention .

The invention relates first of all to a method for down-the-hole drilling, the drilling being carried out by an apparatus, having a drilling device 1 that consists of a casing part 2 and a drilling unit 3 that exists at least during a drilling situation essentially inside thereof. The drilling unit includes; first drilling means 4 at a drilling head I thereof for drilling a center hole and second drilling means 5 for reaming the center hole for the casing part 2, whereby the essentially rotationally symmetrical first drilling means and the second drilling means 4, 5 are coupled mutually first of all in a power transmitting manner in order to carry out cooperation thereof at least during a drilling situation for a rotational motion w4, a feeding motion z4 and/or a hammering motion t4 and on the other hand removably in order to enable removal of the first drilling means from a drilled hole and, whereby the casing part 2 is arranged to be drawn into the hole to be drilled by the first and/or the second dril- ling means; and a flushing flow arrangement 6, whereby a flushing medium is first of all fed by first flushing means 6a for drilling and on the other hand the flushing medium and drilling waste getting generated is removed by second flushing means 6b inside the casing part 2. The flushing medium is led at least partly in connection with the drilling surfaces Pi, P2 of both the first and the second drilling means 4, 5 essentially radially r to an outer periphery of the second dril- ling means 5, in order to lead the flushing medium and the drilling waste inside the casing part 2 through an inlet opening assembly 6bx that is placed in a longitudinal direction s after the first and the second dril- ling means 4, 5.

In the manner described above, an effective flushing is made possible, firstly, over the whole drilling unit's drilling head I, ie. along the first and second dril- ling means, ie. the pilot's and reamer's drilling surfaces PI, P2, and secondly, further along the reamer's side surfaces before the flushing medium and the drilling waste are led inside the casing part 2 to be led further on to the ground. In this way, both optimized placing of the drilling organs, such as the drill bits, and optimized flushing of the reamer's drill bits are made possible, which is to be seen when the solution presenting prior art as shown in figures 1 and 4a is compared to the pictures according to the invention presented e.g. in figures 2, 3 and 4b.

The method according to the invention is being exploited advantageously when operating with a drilling apparatus, in which the drilling head I of the drilling device's 1 drilling unit 3 is formed of a first frame part 4a and a second frame part 5a, wherein the drilling surfaces PI, P2 formed of end surfaces of the above frame parts are provided with drilling organs of the first and the second drilling means 4, 5, such as an integrated drilling part, separate drilling pieces, bits or like and, whereby a casing shoe 8 is exploited in order to couple the drilling unit 3 at an end of the casing part 2, the casing shoe being coupled with the drilling unit 3 by a joint assembly L enabling rotative motion of the casing shoe and limiting its longitudinal movement. In this case, the flushing medium and the drilling waste are being led as an advantageous embodiment according to the principle, shown e.g. in figure 2, inside casing part 2 through one or more inlet openings 6bxl in the casing shoe 8.

Furthermore, as an alternative or as a complementing implementation to the one presented especially in figure 2, according to the advantageous embodiment presented in figure 3, the flushing medium and the drilling waste are being led inside the casing part 2 through one or more inlet openings 6bx2 existing therein.

Furthermore, as an advantageous embodiment with reference to figures 2, 3, 4b, 5 and 6, the flushing medium is led through one or more import openings 6a; 6al that exist on a drilling surface PI of the first drilling means 4, such as the first frame part 4a, to the outer periphery of the second drilling means 5, such as the second frame part 5a, by means of one or more essentially radially directed r and uninterruptedly continuing guide grooves 6a; 6a2 that exist on the drilling surfaces PI, P2 of the first and the second drilling means.

Furthermore, as an advantageous embodiment with reference to e.g. figures 2 and 3, the flushing medium and the drilling waste are being led by one or more flow grooves 6b; 6bl passing essentially longitudinally s on a side surface of the second drilling means 5, such as the second frame part 5a, toward the inlet opening assembly 6bx.

The invention also relates to an apparatus for down- the-hole drilling as presented above, the apparatus having a drilling device 1 that consists of a casing part 2 and a drilling unit 3 that exists at least during a drilling situation essentially inside thereof. The drilling unit includes; first drilling means 4, such as a pilot, and second drilling means 5, such as a reamer, whereby the essentially rotationally symmet- rical first drilling means and the second drilling means 4, 5 are coupled mutually by means of a coupling assembly (which has not been presented in detail in the drawings) first of all in a power transmitting manner in order to carry out cooperation thereof at least during a drilling situation for a rotational motion w4, a feeding motion z4 and/or a hammering motion t4 and on the other hand removably in order to enable removal of the first drilling means from a drilled hole and, whereby the casing part 2 is arranged to be drawn into the hole to be drilled by the first and/or second drilling means; and a flushing flow arrangement 6 first of all in order to feed a flushing medium for drilling by first flushing means 6a and on the other hand in order to remove the flushing medium and drilling waste getting generated by second flushing means 6b inside the casing part 2. In longitudinal direction s after the first and the second drilling means 4, 5 is arranged an inlet opening assembly 6bx for leading of the flushing medium, being led essentially radially r at least partly in connection with the drilling surfaces PI, P2 of both the first and the second drilling means 4, 5 to an outer periphery of the second drilling means 5, and the drilling waste inside the casing part 2.

As an advantageous embodiment of the apparatus, the drilling head I of the drilling device's 1 drilling unit 3 is formed of a first frame part 4a and a second frame part 5a, wherein the drilling surfaces PI, P2 formed of end surfaces of the above frame parts are provided with drilling organs of the first and the second drilling means 4, 5, such as an integrated drilling part, separate drilling pieces, bits or like and, whereby the drilling unit 3 is coupled by a casing shoe 8 at an end of the casing part 2, the casing shoe being coupled with the drilling unit 3 by a joint assembly L enabling rotative motion of the casing shoe and limiting its longitudinal movement. Especially with reference to the advantageous embodiment presented in figure 2, the inlet opening assembly 6bx comprises one or more inlet openings 6bxl in the casing shoe 8 for leading of the flushing medium and the drilling waste inside the casing part 2.

Furthermore as an advantageous embodiment with reference to figure 3, the inlet opening assembly 6bx comprises one or more inlet openings 6bx2 in the casing part 2 for leading of the flushing medium and the drilling waste inside the casing part 2.

Furthermore, according to the advantageous embodiment presented in figure 4b, the drilling surfaces PI, P2 of the first and the second drilling means 4, 5 are provided with essentially radially directed r and uninterruptedly continuing guide grooves 6a; 6a2 in order to lead the flushing medium from one or more import openings 6a; 6al that exist on the drilling surface PI of the first drilling means 4 to the outer periphery of the second drilling means 5.

Furthermore, with reference to figures 2, 3, 4, 5, and 6, a side surface of the second drilling means 5, such as the second frame part 5a, is provided with one or more flow grooves 6b; 6bl passing thereon essentially longitudinally s for leading of the flushing medium and the drilling waste toward the inlet opening assembly 6bx.

Furthermore, especially with reference to figures 5 and 6, when the method and the apparatus according to the invention are applied, an extra flow arrangement 6by may be exploited that on the principle presented e.g. in figure 5 leads a part of the flushing medium straight inside the casing part 2 with one or more extra flow grooves 6byl situated inside the pilot in order to e.g. keep the inlet openings 6bxl in the ca- sing shoe 8 open. Furthermore, in addition to or in lieu of the above, especially with the principle presented in figure 6, the drifting of the flushing medium and the drilling waste inside the casing part 2 may also be arranged partially from the drilling surface with an extra flow groove 6by2 that is led through from inside the pilot or traditionally from between the pilot and the reamer (which, however, has not been presented in the drawings) . The implementations ex- plained above are necessary especially in such drilling locations, where the controlling of the amount of the flushing medium led into the ground is necessary.

It is clear that the invention is not limited to the embodiments presented or described above, but instead it can be modified within the basic idea of the invention according to the needs at any given time. It is thus clear that the constructions of the drilling heads being illustrated in the appended drawings may vary in practice very much merely when being carried out with differing diameters. Instead of the type of embodiments shown e.g. in figures 2 and 3, it is naturally possible to use as the drilling device also other drilling devices that are applicable for the same purpose, in which a casing part without a casing shoe or by transmission thereof is being exploited in connection with the drilling, so that it is most advantageously not rotated when being drawn into the ground. It is not that significant for the method and the apparatus according to the invention, either, how the first and second drilling means are coupled to work, so that most heterogeneous solutions can be exploited as the power transmission assemblies between the same starting from a screw joint locking, which is possible especially thanks to the flushing flow working regardless of the coupling arrangement.

Claims

Claims :

1. Method for down-the-hole drilling, the drilling being carried out by an apparatus, having a dril- ling device (1) that consists of a casing part (2) and a drilling unit (3) that exists at least during a drilling situation essentially inside thereof, which unit includes: first drilling means (4) at a drilling head (I) thereof for drilling a center hole and second dril- ling means (5) for reaming the center hole for the casing part (2), whereby the essentially rotationally symmetrical first drilling means and the second drilling means (4, 5) are coupled mutually first of all in a power transmitting manner in order to carry out coo- peration thereof at least during a drilling situation for a rotational motion (w4), a feeding motion (z4) and/or a hammering motion (t4) and on the other hand removably in order to enable removal of the first drilling means from a drilled hole, whereby the casing part (2) is arranged to be drawn into the hole to be drilled by the first and/or second drilling means; and a flushing flow arrangement (6), whereby a flushing medium is first of all fed by first flushing means (6a) for drilling and on the other hand the flushing medium and drilling waste getting generated is removed by second flushing means (6b) inside the casing part (2) and, whereby the flushing medium is led essentially radially (r) to an outer periphery of the second drilling means (5), in order to lead the flushing medium and the drilling waste inside the casing part (2) through an inlet opening assembly (6bx) that is placed in a longitudinal direction (s) after the first and the second drilling means (4, 5), characterized in that, the flushing medium is led through one or more import openings (6a; 6al) that exist on a drilling surface

(PI) of the first drilling means (4) to the outer periphery of the second drilling means (5) by means of one or more essentially radially directed (r) and unin- terruptedly continuing guide grooves (6a; 6a2) that exist on drilling surfaces (PI, P2) of the first and the second drilling means.

2. Method according to claim 1, when operating with a drilling apparatus, in which the drilling head (I) of the drilling device's (1) drilling unit (3) is formed of a first frame part (4a) and a second frame part (5a), wherein the drilling surfaces (PI, P2) formed of end surfaces of the above frame parts are provided with drilling organs of the first and the second drilling means (4, 5), such as an integrated drilling part, separate drilling pieces, bits or like and, whereby a casing shoe (8) is exploited in order to couple the drilling unit (3) at an end of the casing part (2), the casing shoe being coupled with the drilling unit (3) by a joint assembly (L) enabling rotative motion of the casing shoe and limiting its longitudinal movement, characterized in that, the flushing medium and the drilling waste are being led inside the casing part (2) through one or more inlet openings (6bxl) in the casing shoe (8 ) .

3. Method according to claim 1 or 2, characterized in that, the flushing medium and the drilling waste are being led inside the casing part (2) through one or more inlet openings (6bx2) existing therein.

4. Method according to any of the preceding claims 1-3, characterized in that, the flushing medium and the drilling waste are being led by one or more flow grooves (6b; 6bl) passing essentially longitudinally (s) on a side surface of the second drilling means (5), such as the second frame part (5a), toward the inlet opening assembly (6bx).

5. Apparatus for down-the-hole drilling, the apparatus, having a drilling device (1) that consists of a casing part (2) and a drilling unit (3) that exists at least during a drilling situation essentially inside thereof, which unit includes: first drilling means (4) at a drilling head (I) thereof for drilling a center hole and second drilling means (5) for reaming the center hole for the casing part (2), whereby the essentially rotationally symmetrical first drilling means and the second drilling means (4, 5) are coupled mutually b y means of a coupling assembly first of all in a power transmitting manner in order to carry out cooperation thereof at least during a drilling situation for a rotational motion (w4), a feeding motion (z4) and/or a hammering motion (t4) and on the other hand removably in order to enable removal of the first dril- ling means from a drilled hole and, whereby the casing part (2) is arranged to be drawn into the hole to be drilled by the first and/or second drilling means; and a flushing flow arrangement (6) first of all in order to feed a flushing medium for drilling by first flushing means (6a) and on the other hand in order to remove the flushing medium and drilling waste getting generated by second flushing means (6b) inside the casing part (2), whereby in a longitudinal direction s after the first and the second drilling means (4, 5) is arranged an inlet opening assembly (6bx) for leading of the flushing medium, being led radially (r) to an outer periphery of the second drilling means (5) , and the drilling waste inside the casing part (2), characterized in that, the drilling surfaces (PI, P2) of the first and the second drilling means (4, 5) are provided with essentially radially directed (r) and uninterruptedly continuing guide grooves (6a; 6a2) in order to lead the flushing medium from one or more import openings (6a; 6al) that exist on the drilling surface (PI) of the first drilling means (4) to the outer periphery of the second drilling means (5) .

6. Apparatus according to claim 5, in which the drilling head (I) of the drilling device's (1) drilling unit (3) is formed of a first frame part (4a) and a second frame part (5a), wherein the drilling surfaces (PI, P2) formed of end surfaces of the above frame parts are provided with drilling organs of the first and the second drilling means (4, 5), such as an integrated drilling part, separate drilling pieces, bits or like and, whereby the drilling unit (3) is coupled by a casing shoe (8) at an end of the casing part (2), the casing shoe being coupled with the drilling unit (3) by a joint assembly (L) enabling rotative motion of the casing shoe and limiting its longitudinal movement, characterized in that, the inlet opening assembly (6bx) comprises one or more inlet openings (6bxl) in the casing shoe (8) for leading of the flushing medium and the drilling waste inside the casing part (2).

7. Method according to claim 5 or 6, character i- zed in that, the inlet opening assembly (6bx) comprises one or more inlet openings (6bx2) in the casing part (2) for leading of the flushing medium and the drilling waste inside the casing part (2) .

8. Method according to any of the preceding claims 5-7, characterized in that, a side surface of the second drilling means (5), such as the second frame part (5a), is provided with one or more flow grooves (6b; 6bl) passing thereon essentially longitudinally (s) for leading of the flushing medium and the drilling waste toward the inlet opening assembly (6bx) .