EP2300682A1

EP2300682A1 - Method and drilling apparatus for drilling

Info

Publication number: EP2300682A1
Application number: EP09769412A
Authority: EP
Inventors: Antti Virjula; Kai Gylling
Original assignee: Atlas Copco Rotex Oy AB
Current assignee: Tercope Finland Oy
Priority date: 2008-06-26
Filing date: 2009-06-10
Publication date: 2011-03-30
Also published as: WO2009156569A1; EP2300682A4; FI20085643A0

Abstract

The invention relates to a method for drilling and a drilling apparatus operating according to the method. The drilling apparatus have a drilling device (1) that, comprises a casing part (2) and an drilling unit (3), in the drilling head (I) of which there are first drilling means (4) for drilling a center hole and second drilling means (5) for reaming of the center hole for the casing part (2). During the drilling situation the first drilling means (4) are coupled power- transmittedly and in order to enable removal of the same from a hole removably with the second drilling means (5). The first drilling means (4) driving the second drilling means (5) during the drilling situation and the second drilling means (5), being rotatable in respect with the casing part (2) that is to be drawn into the hole to be drilled without a rotative motion thereof, are coupled with each other immovably for a cooperating rotating motion (w4), feeding motion (z4) and/or hammering motion (t4) thereof by means of a coupling mechanism (X) that is movable into a locking position (XI) and a releasing position (XII).

Description

Method and drilling apparatus for drilling

The invention relates to a method for drilling, being carried out by a drilling apparatus, having a drilling device that comprises a casing part and an at least during a drilling situation essentially inside thereof existing drilling unit. In the drilling head of the drilling unit there are at least first drilling means for drilling a center hole and second drilling means for reaming of the center hole for the casing part by means of a drill surface, continuing essentially uniformly radially, when viewed in a cross section perpendicular to the longitudinal direction of the drilling unit. The drilling unit comprises furthermore a flushing flow arrangement for flushing of drilling waste being generated by feeding flushing medium by a first flow assembly for the drilling and by removing drilling waste being generated by a second flow assembly essentially inside the casing part. At least during the drilling situation the first drilling means are coupled power-transmittedly and in order to enable removal of the same from a hole removably with the second drilling means. Furthermore the casing part is arranged to be drawn into the hole to be drilled by the first and/or the second drilling means.

For example in patent document FI 75650 there has been presented a boring tool, which is meant for boring and/or hammer drilling, to be used in connection with a drill rod unit placed inside a core pipe. The boring tool to be attached at the front end of the drill rod unit has a center drill, being provided with a cutting unit, and an eccentric reaming drill, being placed behind the center drill, the reaming drill having also a cutting unit. The reaming drill moves with respect to the center drill between a drilling position, in which it is positioned to the side in front of the core pipe, and a return position, in which it is withdrawn in radial direction inside the core pipe. Deviating from earlier solutions, in which the center drill is in most cases provided with four cutting parts directed radially and being made of hard metal, the reamer for its part comprising either one or two radially directed cutting parts made of hard metal, in the solution according to the document in question, the cutting parts are replaced by bit parts being arranged in a certain manner. With the solution presented in the document such constructions of the center drill and the reaming drill have been desired that the operating time of the boring tool will be as long as possible.

It is characteristic for use of the type of drilling apparatuses described above that the hole to be drilled to the ground is reamed by an eccentrically operating reaming drill. This leads to most differing kinds of problems. First of all the drilling motion of the reaming drill taking place eccentrically causes high torsion stress to the drill rod unit. In this case it is not possible to take optimally advantage of the operating efficiency of the drilling device due to high breakage risk of the drill rod unit, particularly breaking off thereof. On the other hand, a problem in practice in a drilling situation is often the returning of the reaming drill to its return position, which is due to ground substance, being collected between the reaming drill and the center drill. In order to get the reaming drill back to its return position, usually a repeated back and forth movement of the drilling device is required. Naturally when e.g. a too high operating efficiency is being used or when the materials of the drilling device parts have a lowered fatigue resistance, there is a high risk for breakage of the drill rod unit.

On the other hand e.g. in Finnish patent number 94891 there has been presented a boring tool, which has two or three blocks moving in respect with each other at a same plane, forming a drill bit of the boring tool. The boring tool in question can be used as described above in a way that in a drilling situation the bit blocks are in an ejected position, in which case the bit parts placed therein drill a hole that is essentially greater than the casing part. After the drilling situation the casing part can be left in the hole and the drill rod unit inside the same with its bit blocks can be removed as a whole from the hole by moving the bit blocks with respect to each other in a way that they get withdrawn to a shape that is smaller than the free internal diameter of the casing part. In the solution in question, the bit blocks are arranged movable in respect with each other by coupling each one thereof by a single guiding pin with a guide part supporting the bit blocks, which pins depending on the rotation direction of the guide part bring about protrusion of the bit blocks or the same coming together in cooperation with guide grooves in the guide part.

In the patent in question several differing solutions have been presented in order to couple these guiding pins with the bit blocks . The biggest problem in practice of this type of solutions is, however, the high stresses directed to the guiding pins, in which case particularly when drilling stony ground, the durability of the guide pins is under heavy strain, because very high torsion stresses as well as torque loads are directed thereto. This is why the functionality of the guiding pins particularly in drilling to be performed under demanding circumstances is very unreliable, because when drilling e.g. rock a continuous fatigue load is directed to the pins, which furthermore weakens tensile properties thereof in longer lasting use. The biggest problem related to the asymmetric reaming drills or reamers of the type described above is that the drill surface of the drilling means thereof is radially non-uniform, when viewed in a cross section perpendicular to the longitudinal direction of the drill unit, which causes continuous strokes and strain both to the structures of the drill unit as well as to the operating apparatus driving the same, requiring an unnecessarily high operating efficiency. Furthermore the operating time of this type of drill bits remains always shorter than the same of so called symmetrical ring drill bits.

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. The drilling head of the drilling unit of the drilling apparatus according to this patent, 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 the pilot and the 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 off from the 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 belonging to the counterpart surface arrangement, which connects the said drilling means together for a drilling situation unrotatively in respect with each other and in both directions longitudinally, which, in other words, is being 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 solution in question has got very good feedback from professionals in the field and a very big market share both domestically and abroad. The good success of the solution in question is based on the totally new construction in its time, which enables transmitting of flushing medium to the drilling surface and removing of same therefrom advantageously so that other structures of the drilling apparatus are not weakened, being the case with earlier solutions. As a version developed from the structure according to the patent mentioned above, also drilling apparatuses have been used, in which the reamer comprises a ring drill bit that is free from the casing part and/or from casing shoe placed at the end thereof, but which can be coupled with the center drill or the pilot on a quick locking principle, such as by a bayonet locking, whereby in this solution also only the pilot is removed from the hole after the drilling.

Also for the part of this kind of a solution, having a symmetrical reamer, there has been found a need for further development particularly for the part of the merely mechanical coupling between the pilot and the reamer e.g. due to the fact that, when drilling is being continued after the ground pipe drilling, the internal dimensions of the parts that are left in the ground with the ground pipe must be as big as possible. In drilling units being carried out with fixed projections, there is thus a need to make the coupling projections as small as possible, which makes faster wearing out thereof and increases risk for breakage.

The method and the drilling apparatus exploiting the same according to this invention are aimed to achieve a decisive improvement in the problems described above and thus to raise substantially the level of prior art. To bring about this aim, the method and the drilling apparatus according to the invention are primarily characterized by what has been presented in the characterizing parts of the independent claims related to the same.

As the most important advantages of the method and the drilling apparatus exploiting the same, simplicity and operating reliability thereof and equipment applicable for the same may be mentioned first of all thanks to the fact that in connection therewith already existing drilling apparatus structures can be exploited that have been found effective already in practice, whereby, when taking advantage of the invention in connection therewith, driving of the second drilling means during a drilling situation by the first drilling means is enabled and thus also pulling of the casing part into the hole to be drilled without its rotation motion. Thanks to this, the energy consumption in drilling is optimal because energy does not get wasted during drilling for rotating of the casing part. An advantage of the drilling apparatus taking advantage of the method according to the invention, is thus the simplicity and efficiency of the structures of the parts belonging to the same as well as of its use, by virtue of which particularly e.g. unnecessarily massive drilling apparatus structures can be avoided. This together with the rotationally symmetrical reamer makes possible for its part also an optimum dimensioning of the capacity of the operating unit driving the drilling apparatus. Thanks to the coupling mechanism being exploited in the invention, the total wall thickness of the second drilling means or the reamer can be exploited merely for power transmission, which enables use of larger pass through diameters structurally and, what is the most important thing, with stronger structures with a view to mechanics of materials. Advantageous embodiments of the method and the drilling apparatus according to the invention have been presented in the dependent claims related thereto.

In the following description the invention is being described in detail with reference to the enclosed drawings, in which

in figure 1 is shown as a longitudinal cross section an advantageous solution according to prior art, in which there has been exploited symmetrical second drilling means or a so called ring reamer,

in figure 2 is shown as a partial cross section a drilling unit of an advantageous drilling apparatus exploiting the method according to the invention,

in figure 3 is shown a first frame part being exploited in the embodiment shown in figure 2, the coupling mechanism thereof being in a locking position,

in figure 4 is shown the embodiment according to figure 2, in which the coupling mechanism is in a release position,

in figure 5 is shown putting together of the implementation presented in figure 2 from the first and the second frame parts, and in figure 6 is shown the embodiment shown in figure 2 as a partially sectioned perspective view.

The invention relates to a method for drilling, being carried out by a drilling apparatus, having a drilling device 1 that comprises a casing part 2 and an at least during a drilling situation essentially inside thereof existing drilling unit 3, in the drilling head I of which there are at least first drilling means 4 for drilling a center hole and second drilling means 5 for reaming of the center hole for the casing part 2 by means of a drill surface, continuing essentially uniformly radially, when viewed in a cross section perpendicular to the longitudinal direction s of the drilling unit. The drilling unit comprises furthermore a flushing flow arrangement 6 for flushing of drilling waste being generated by feeding flushing medium by a first flow assembly βa for the drilling and by removing drilling waste being generated by a second flow assembly 6 essentially inside the casing part 2. At least during the drilling situation the first drilling means 4 ^'are coupled power-transmittedly and in order to enable removal of the same from a hole removably with the second drilling means 5. Furthermore the casing part 2 is arranged to be drawn into the hole to be drilled by the first and/or the second drilling means. The first drilling means 4 driving the second drilling means 5 during the drilling situation and the second drilling means 5, being rotatable in respect with the casing part 2 that is to be drawn into the hole to be drilled without a rotative motion thereof, are coupled with each other immovably for a cooperating rotating motion w4, feeding motion z4 and/or hammering motion t4 thereof by means of a coupling mechanism X that is movable into a locking position XI and a releasing position XII. The method is being applied advantageously when operating with a drilling apparatus, the drilling device's 1 drilling head I of the drilling unit 3 consisting of a first frame part 4a and a second frame part 5a, both of the above being essentially rotationally symmetrical, whereby at the drilling surfaces of the frame parts there are arranged e.g. as shown in figure 1 drilling organs 10a, 10b, such as an integrated drilling part, separate drilling pieces, bits or the like, of the first and second drilling means 4, 5. Correspondingly the flushing medium and/or the drilling waste is being led inside the drilling unit 3, such as between the said frame parts 4a, 5a, through a space between the first frame part 4a and the casing part 2 and/or in a corresponding manner. The coupling mechanism X comprises advantageously a recess- projection assembly Xl, X2 between the first and the second frame parts 4a, 5a, whereby the projection assembly Xl thereof is being moved by means of mechanically, electrically and/or pressure medium operated actuator means X3 essentially in a radial direction r into a locking position XI inside the recess assembly X2.

Furthermore as an advantageous embodiment the method is being exploited when using a drilling apparatus, in which the drilling unit 3 is coupled e.g. on the principle, shown in figures 1 or 2 with the end of the casing part 2 by a casing shoe 8, being connected to the drilling unit 3 by means of a joint assembly L that enables rotative motion of the casing shoe and limits its longitudinal movement.

The locking between the drilling means 4, 5 is achieved particularly with reference to figures 3 - 5 by moving the projection assembly Xl in connection with the first drilling means 4, such as in the first frame part 4a inside the recess assembly X2 in connection with the second drilling means 5, such as in the second frame part 5a, which results a composition e.g. according to figures 2 and 6 (it should be noted that the guide hole XI 'of the coupling mechanism in the first frame part 4a is shown empty in figure 2) .

The invention relates also to a drilling apparatus as described above, the drilling unit 3 thereof being provided with a coupling mechanism X that is movable into a locking position XI and a releasing position XII in order to couple the first drilling means 4 driving the second drilling means 5 during the drilling situation and the second drilling means 5, being rotatable in respect with the casing part 2 that is to be drawn into the hole to be drilled without a rotative motion thereof, with each other immovably for a cooperating rotating motion w4, feeding motion z4 and/or hammering motion t4 thereof.

A drilling head I of the drilling device' s 1 drilling unit 3 belonging to the drilling apparatus consists advantageously of a composition described above, whereby a coupling mechanism X being provided therewith comprises a recess-projection assembly Xl, X2 between the first and the second frame parts 4a, 5a, whereby the projection assembly Xl thereof is arranged movable as shown e.g. in figures 3 and 4 essentially in a radial direction r. As an advantageous embodiment of the drilling apparatus according to the invention, the moving parts of the coupling mechanism X, such as the projection assembly Xl is arranged essentially in connection with the first drilling means 4, such as the first frame part 4a.

Particularly with reference to the advantageous implementation shown in figure 3, the moving part belonging to the coupling mechanism X, such as the projection assembly Xl comprises one or more locking pins or like, being placed preferably symmetrically in the first frame part 4a, the pin being limitedly movable in its direction of motion r. In this case a locking pin is coupled with a guide hole Xl' in the first frame part in a way that a widened base part in connection with a widening in the guide hole limit the protrusion of the locking pin.

Furthermore as an advantageous embodiment the coupling mechanism X is arranged at least partly operable by mechanical actuator means X3, such as by eccentric arrangements within the first frame part 4a or correspondingly. In this connection it is possible to couple the eccentric arrangement to operate in an ordinary manner as such e.g. in a way that the eccentric arrangement inside the first frame part 4a gets placed in a position enabling a locking position

XI of the locking pin/pins by rotating the drilling unit 3 in an opposite direction with respect to its normal drilling direction w4.

Furthermore as an advantageous alternative or complementing embodiment with respect to the above, the coupling mechanism X is arranged operable by pressure medium operated actuator means X3, such as by assemblies coupled with the flushing medium and/or hammering medium system of the drilling unit 3 or correspondingly, and/or at least partly operable by electrically operated actuator means X3.

It is obvious that the invention is not limited to those embodiments, being presented or described above, but instead it can be modified within the basic idea of the invention according to embodiments at any given time. So, e.g. deviating from the down the hole drill shown in figure 1, the drill unit can also operate on so called reverse circulation e.g. for sampling drilling, whereby the flushing medium is lead from the edges of the drill unit to an exhaust channel at its center. It is naturally possible to arrange the profile of the coupling mechanism' s movable part most applicable for the purpose at any given time e.g. by using a locking pin having e.g. a rectangular or polygonal cross section and/or that is rounded by its end or conical. Naturally it is correspondingly possible to arrange the movable part of the coupling mechanism to be partly pressure medium and/or electrically operated in order to get it locked at its locking position so that the reverse motion of the locking pin or pins is carried out mechanically e.g. spring operated etc.

Claims

Claims :

1. Method for drilling, being carried out by a drilling apparatus, having a drilling device (1) that comprises a casing part (2) and an at least during a drilling situation essentially inside thereof existing drilling unit (3) , in the drilling head (I) of which there are at least first drilling means (4) for drilling a center hole and second drilling means (5) for reaming of the center hole for the casing part (2) by means of a drill surface, continuing essentially uniformly radially, when viewed in a cross section perpendicular to the longitudinal direction (s) of the drilling unit, as well as a flushing flow arrangement (6) for flushing of drilling waste being generated by feeding flushing medium by a first flow assembly (βa) for the drilling and by removing drilling waste being generated by a second flow assembly (6) essentially inside the casing part (2), whereby at least during the drilling situation the first drilling means (4) are coupled power-transmittedly and in order to enable removal of the same from a hole removably with the second drilling means (5), and whereby the casing part (2) is arranged to be drawn into the hole to be drilled by the first and/or the second drilling means, characterized in that the first drilling means (4) driving the second drilling means (5) during the drilling situation and the second drilling means (5), being rotatable in respect with the casing part (2) that is to be drawn into the hole to be drilled without a rotative motion thereof, are coupled with each other immovably for a cooperating rotating motion (w4), feeding motion (z4) and/or hammering motion (t4) thereof by means of a coupling mechanism (X) that is movable into a locking position (XI) and a releasing position (XII) .

2. Method according to claim 1 when operating with a drilling apparatus, the drilling device's (1) drilling head (I) of the drilling unit (3) consisting of a first frame part (4a) and a second frame part (5a), both of the above being essentially rotationally symmetrical, whereby at the drilling surfaces of the frame parts there are arranged drilling organs (10a, 10b) , such as an integrated drilling part, separate drilling pieces, bits or the like, of the first and second drilling means (4, 5) and, whereby the flushing medium and/or the drilling waste is being led inside the drilling unit (3), such as between the said frame parts (4a, 5a), through a space between the first frame part (4a) and the casing part (2) and/or in a corresponding manner, and/or whereby a casing shoe (8) is being exploited in order to couple the drilling unit (3) with the end of the casing part (2), the casing shoe being connected to the drilling unit (3) by means of a joint assembly (L) that enables a rotative motion of the casing shoe and limits its longitudinal movement, characterized in that the coupling mechanism

(X) comprises a recess-projection assembly (Xl, X2 ) between the first and the second frame parts (4a, 5a), whereby the projection assembly (Xl) thereof is being moved by means of mechanically, electrically and/or pressure medium operated actuator means (X3) essentially in a radial direction (r) into a locking position (XI) inside the recess assembly (X2).

3. Method according to claim 1 or 2, characterized in that the locking between the drilling means (4, 5) is achieved by moving the projection assembly (Xl) in connection with the first drilling means (4), such as in the first frame part (4a) inside the recess assembly (X2) in connection with the second drilling means (5), such as in the second frame part (5a) .

4. Drilling apparatus, having a drilling device

(1) that comprises a casing part (2) and an at least during a drilling situation essentially inside thereof existing drilling unit (3), in the drilling head (I) of which there are at least first drilling means (4) for drilling a center hole and second drilling means (5) for reaming of the center hole for the casing part (2) by means of a drill surface, continuing essentially uniformly radially, when viewed in a cross section perpendicular to the longitudinal direction (s) of the drilling unit, as well as a flushing flow arrangement (6) for flushing of drilling waste being generated by feeding flushing medium by a first flow assembly (6a) for the drilling and by removing drilling waste being generated by a second flow assembly (6) essentially inside the casing part (2), whereby at least during the drilling situation the first drilling means (4) are coupled power-transmittedly and in order to enable removal of the same from a hole removably with the second drilling means (5) , and whereby the casing part

(2) is arranged to be drawn into the hole to be drilled by the first and/or the second drilling means, characterized in that the drilling unit (3) is provided with a coupling mechanism (X) that is movable into a locking position (XI) and a releasing position (XII) in order to couple the first drilling means (4) driving the second drilling means (5) during the drilling situation and the second drilling means (5), being rotatable in respect with the casing part (2) that is to be drawn into the hole to be drilled without a rotative motion thereof, with each other immovably for a cooperating rotating motion (w4), feeding motion (z4) and/or hammering motion (t4) thereof.

5. Drilling apparatus according to claim 4, the drilling device's (1) drilling head (I) of the drilling unit (3) consisting of a first frame part (4a) and a second frame part (5a), both of the above being essentially rotationally symmetrical, whereby at the drilling surfaces of the frame parts there are arranged drilling organs (10a, 10b) , such as an integrated drilling part, separate drilling pieces, bits or the like, of the first and second drilling means (4, 5) and, whereby the flushing medium and/or the drilling waste may be led inside the drilling unit (3), such as between the said frame parts (4a, 5a) , through a space between the first frame part (4a) and the casing part (2) and/or in a corresponding manner, and/or whereby the drilling unit (3) is coupled with the end of the casing part (2) by a casing shoe (8), being connected to the drilling unit (3) by means of a joint assembly (L) that enables a rotative motion of the casing shoe and limits its longitudinal movement, characterized in that the coupling mechanism (X) comprises a recess- projection assembly (Xl, X2) between the first and the second frame parts (4a, 5a), whereby the projection assembly (Xl) thereof is arranged movable essentially in a radial direction (r) .

6. Drilling apparatus according to claim 4 or 5, characterized in that the moving parts of the coupling mechanism (X), such as the projection assembly (Xl) is arranged essentially in connection with the first drilling means (4), such as the first frame part (4a).

7. Drilling apparatus according to any of the preceding claims 4-6, characterized in that the moving part belonging to the coupling mechanism (X) , such as the projection assembly (Xl) comprises one or more locking pins or like, being placed preferably symmetrically in the first frame part (4a) , the pin being limitedly movable in its direction of motion (r) .

8. Drilling apparatus according to any of the preceding claims 4-7, characterized in that the coupling mechanism (X) is arranged at least partly operable by mechanical actuator means (X3) , such as by eccentrical arrangements within the first frame part (4a) or correspondingly.

9. Drilling apparatus according to any of the preceding claims 4-8, characterized in that the coupling mechanism (X) is arranged operable by pressure medium operated actuator means (X3) , such as by assemblies coupled with the flushing medium and/or hammering medium system of the drilling unit (3) or correspondingly.

10. Drilling apparatus according to any of the preceding claims 4-8, characterized in that the coupling mechanism (X) is arranged at least partly operable by electrically operated actuator means (X3) .