AU6040500A

AU6040500A - A sleeve arrangement

Info

Publication number: AU6040500A
Application number: AU60405/00A
Authority: AU
Inventors: Lars Liw
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-07-02
Filing date: 2000-06-30
Publication date: 2001-01-22
Also published as: SE9902545D0; SE9902545L; NO20020009D0; SE516885C2; WO2001002695A1; NO20020009L; CA2377829A1

Description

WO 01/02695 PCT/SE00/01395 1 A sleeve arrangement The present invention relates to a sleeve arrangement according to the preamble of Patent Claim 1 and can be used for rock drills. This application 5 is concurrent with Swedish patent application No. 9902544-7. When rock is drilled to great depths, for example in diamond drilling, it is important that the various components in the drill should be configured such that the least possible wear occurs. A bore hole of this type can be very deep, so that wear and thermal influence upon the equipment subject the equipment to high 10 stresses. In order to be able to guide the drill in the desired direction, the drilling device is provided with a guide mechanism. This guide mechanism can be achieved through the use of an outer sleeve, which is non-rotating during drilling and has an inner rotary core barrel. In order to be able to lock the outer sleeve arrangement against the wall of the rock hole, guide sleeves, 15 as they are known, having extensible supporting units, are used. Guide sleeves can also have other fields of application, which are not described here. It is of extreme importance that this outer tube can be held in a locked radial 20 position during drilling, so that the guide mechanism reaches its full function. This is achieved according to EP 95 905 256.4, in which a sleeve device prevents an outer sleeve from rotating whilst an inner tube, a core barrel, rotates, at the same time as a sleeve arrangement has been arranged with lugs, or supporting units, which are mutually aligned in the axial 25 direction. That is to say, the sleeve arrangement is provided with a plurality of rings of lugs. These lugs, or supporting units, each have a protruding edge, which protruding edges are also placed one behind the other in the axial direction of the drilling device. In the drilling process, those edges which are placed above the lowest placed edges thereby follow behind in 30 grooves in the bore hole wall made by the lowermost edges. In this way, the sleeve arrangement is guided in the axial direction. At a distance below this WO 01/02695 PCT/SE00/01395 2 sleeve arrangement, a guide mechanism is arranged to enable the drill to be guided. The guide mechanism can comprise, for example, a section which laterally displaces the centre or an articulated section in the outer sleeve. 5 Guide sleeves can be arranged in various ways on the outer sleeve arrangement. According to EP 95 905 256.4, the guide cage is continually moved together with the core barrel as the drilling progresses. During the drilling, drilling fluid is fed under pressure from ground level through the interior of the drilling tubes down to the core barrel. This drilling fluid 10 pressure brings about an extension of the supporting units. The extensible supporting units according to the prior art are pushed out from the body of the guide cage by means of the excess pressure generated by the drilling fluid. For the achievement of a seal, according to the prior art an elastic stocking or the like is used inside the guide cage to produce a seal having a 15 function of the supporting units which is reflective of the water pressure. The invention according to EP 95 905 256.4 works very satisfactorily. In practical tests at great depths, it has been shown, however, that this elastic stocking is not always capable of withstanding the high temperature which occurs at great depths. In extreme cases, the temperature down in the bore 20 hole at great depth can be up to +130 degrees Celsius. In the absence of drilling liquid pressure, the supporting units are forced out somewhat against the rock wall owing to the fact that the elastic stocking is always bearing against the supporting units and presses these outwards. It has also been shown that, when the outer sleeve arrangement of the core barrel is raised, it 25 can happen that the supporting units are forced against the rock hole wall as the drilling equipment is raised. This means unnecessary wear on the said guide units and their lugs/edges. A drive shaft having a core barrel to which a cutter head is connected shall 30 be able to rotate inside the non-rotating outer sleeve. With suitable placement of the guide mechanism (for example a section of the outer sleeve WO 01/02695 PCT/SE00/01395 3 which laterally displaces the centre) beneath the sleeve arrangement according to the invention, the cutter head shall be able to be guided in the desired direction by a deflection of, for example, the section which laterally displaces the centre, that is to say the guide mechanism. The important thing 5 is that the sleeve arrangement, during drilling, can lock the outer sleeve against the bore hole, whereupon the guide mechanism, which is placed at a distance below the sleeve arrangement, can bring about a deflection of the core barrel and hence of the non-rotating outer tube, which will constantly be able to accompany the drilling device in the axial direction. It is 10 advantageous if the sleeve arrangement occupies as little space as possible. It is desirable for the drilling to continue in one stage up to the point at which the lowermost drilling tube, the core barrel, is filled with a drill core (also referred to as product or drilling sample) and therefore has to be raised 15 in order to be emptied. As described in the aforementioned accompanying Swedish patent application, the guide cage according to the present invention holds the guide mechanism in a radially fixed position during the actual drilling process. It is also desirable for the guide cage to be able to hold the non-rotating outer tube in a radially non-rotatable position, whilst the guide 20 cage is simultaneously able to be moved downwards in the bore hole as the drilling process proceeds. In the emptying of the core barrel, virtually all the drilling equipment, apart from the core barrel, is left in its position in the bore hole as the core barrel, encompassing a rock sample, etc., is raised to the ground surface using, for example, a wire-line method, as it is known. 25 It is desirable to maximize the measurement of the inner diameter in relation to that of the outer diameter, which measurement is dependent upon the diameter of the cutter head and the desired diameter of the bore hole. It is therefore desirable that the guide cage should comprise as few parts as 30 possible and that the supporting unit(s) should be able to engage directly in the wall of the bore hole. It is also desirable that the supporting unit(s) WO 01/02695 PCT/SE00/01395 4 should have a perfect seal against the body of the guide cage and that this seal should be heat-resistant. Another requirement is also that the supporting unit(s) should not press against the wall of the bore hole as the whole of the drilling device is raised. 5 A principal object of the invention is to produce a sleeve arrangement for the said guide mechanism, by means of which sleeve arrangement the drilling shall be able to proceed in constant alignment in the bore hole. The sleeve arrangement shall be able to be fixable in a direct-acting manner radially 10 against the wall of the rock hole in order thereby to be able to secure the non-rotating outer sleeve and, in the absence of drilling liquid pressure, to be able to be released easily without the supporting unit(s) lying with pressure upon the wall of the bore hole. 15 Another object of the invention is to produce a sleeve arrangement consisting of as few parts as possible, that is to say having as few supporting units as possible, but which simultaneously provides a satisfactory engagement in the wall of the bore hole in order to prevent rotation of the guide mechanism. In this way, reliability is increased and wear reduced. 20 A further object is to produce a sleeve arrangement which can tolerate the high temperature which is present at great depths. One object is also to produce a sleeve arrangement which can remain in the 25 bore hole together with the outer tube in a non-rotatable position, even as the core barrel is being raised. The above-stated principal object is achieved with a sleeve arrangement which has acquired the characteristics defined in Patent Claim 1. Further 30 solutions to the objects and characteristics of the invention are defined in the other patent claims.

WO 01/02695 PCT/SE00/01395 5 With a sleeve arrangement of this kind, the guide cage is realized such that it is fixed against the bore hole wall, without its supporting units bearing against the bore hole wall as the sleeve is raised, and can further be used 5 with a small number of parts in the arrangement. The supporting unit is brought into engagement under the direct action of the drilling liquid pressure and is provided with a heat-resistant sealing device, which results in the realization of an uncomplicated and reliable guide cage. 10 The invention is described in greater detail below on the basis of two illustrative embodiments and with reference to the appended drawings, in which Fig. 1 shows, in diagrammatic representation, a general perspective view 15 of the lower end of a drilling device for rock drilling according to the invention, with associated sleeve arrangement and guide mechanism, Fig. 2 shows, in diagrammatic representation, a longitudinal section through a section of the sleeve arrangement disposed on the drilling device in Fig. 1, 20 Fig. 3 shows, in diagrammatic representation, a cross section of the sleeve arrangement in Fig. 2 according to a first illustrative embodiment, Fig. 4 shows, in diagrammatic representation, an enlarged-scale cross section 25 of the sleeve arrangement in Fig. 2 according to a second illustrative embodiment, and Fig. 5 shows, in diagrammatic representation, a top view of a supporting unit in Figs 1-4 on an enlarged scale. 30 WO 01/02695 PCT/SE00/01395 6 As shown in Fig. 1, part of a drilling tube 11 is located in a bore hole 9. The principal parts of a rock drill can be said to be the drive mechanism (not shown), a number of drilling tubes 11 connectable to an outer sleeve device 5, and a core barrel 6 having a cutter head 4. The rock drill shown in the 5 figure is guidable. The core barrel 6 has the task of taking up bored-out material. The drilling tube 11 runs from the ground surface m. First, a guide instrument 15 is arranged on the drilling tube 11, which instrument 15 uses a placed cam 16 to detect a rotational position for the outer sleeve device 5 placed further down in the bore hole 9, which cam forces the outer sleeve 10 device 5 towards the bore hole wall 9, whereupon deviation occurs and hence the cutter head 4 placed at the lower end of the core barrel 6 is able to be guided. This cam 16 forms part of a guide mechanism 14. The cam 16 is exaggerated in size in the figure. After the guide instrument 15 there is a sleeve arrangement 1 according to the invention. At a distance below the 15 sleeve arrangement 1, the guide mechanism 14 is located. Neither the guide instrument 15, the cam 16, nor the way in which the guide mechanism 14 is arranged to guide the cutter head 4, constitute any part of the invention and are not therefore described in greater detail. A suitable embodiment of the guide instrument 15 for aligning the cam 16 in the correct rotational position 20 is described in Swedish patent 8503553-3. An example of a guide mechanism is described in EP 95 905 256.4. According to this document, the guide mechanism accompanies the drilling tube downwards during drilling to the point where the drilling tube has to be raised and emptied. Another example of a guide mechanism is described in a Swedish patent application 25 concurrent with the present application. When the core barrel 6 is emptied, a core sample (not shown) is taken up, without the outer sleeve device 5 needing to be raised. The sleeve arrangement 1 according to the invention described in this application can be arranged for the said guide mechanism. Neither the guide mechanism nor the drilling tubes are required to be raised 30 in connection with the taking up of the core sample (not shown). The drill arrangement according to the Swedish application concurrent with this one WO 01/02695 PCT/SE00/01395 7 means that virtually only the core barrel 6 is intended to be disconnected and hence to be able to raised to the ground surface m. The core barrel 6, at the same time as it is able to house the core sample, constitutes a guide means (not shown), which acts upon a device (not shown) in the guide mechanism 5 14 for deflection of the outer sleeve device 5. Arranged on the sleeve arrangement 1 are supporting units 7, which are adjustable in the manner which is diagrammatically illustrated. The supporting units 7 extend in the direction of the bore hole and are arranged in a guiding sleeve 3 in the sleeve arrangement 1. 10 Figs. 2 and 3 show an example of an embodiment of the sleeve arrangement, in which three arranged, adjustable supporting units 7 are disposed in the wall of the guiding sleeve 3. The supporting units 7 according to this embodiment are arranged in the wall of the sleeve 3 and in a ring at an angle 15 of 120 degrees between one another. Fig. 2 shows the sleeve arrangement 1 in cross section. The sleeve arrangement 1 comprises, inter alia, the sleeve 3 with three through-recesses 15 (only one recess 15 and one supporting unit 7 are shown in the figure). 20 Each recess 15 has a circumference corresponding to the body of the supporting unit 7. In the through-recesses 15, the supporting units 7 are arranged such that they run freely. The sleeve arrangement 1 is arranged on the outer sleeve device 5, which is non-rotating during drilling. The outer sleeve device 5 is provided with an upper and a lower guide cage connection 25 5a, 5b, for example having threaded sections (not shown) for tightening of the guiding sleeve 3. An internal stop sleeve 20, which limits the motion for the supporting units 7, is arranged centrally in the sleeve arrangement 1. The stop sleeve 20 prevents the supporting units 7 from falling into the sleeve arrangement 1 when the core barrel 6 is raised to the ground surface m (see 30 Fig. 1). This is occasionally done for emptying of the care barrel 6 or orientation of the equipment, etc. The rotation of the core barrel 6 is WO 01/02695 PCT/SE00/01395 8 achieved with a drive shaft 25. Sealing devices have been arranged at the transition between the upper guide cage connection 5a and the sleeve arrangement 1 and between the lower guide cage connection 5b and the sleeve arrangement 1. These sealing devices comprise, for example, sealing 5 rings 24 made from a ceramic, heat-resistant material. Locking rings 26 have been arranged in grooves 27 on the inside of the guide cage connections 5a, 5b in order to fix the sealing rings 24 against the sleeve arrangement 1. Drilling fluid is generally used in rock drilling for lubrication and cooling. The cutter head 4 must therefore be provided with drilling fluid or water. 10 According to the illustrative embodiment, a water duct 29 has been arranged in the drive shaft 25. At the ground surface m (see Fig. 1), pressurized drilling fluid is transported through the drilling tube 11 of the drilling equipment (see Fig. 1) and onward through the water duct 29 down to the cutter head 4 via the sleeve arrangement 1. Radial transverse ducts 30 for the 15 supply and discharge of the drilling liquid have also been realized in the drive shaft 25, which transverse ducts 30 have the effect that drilling fluid pressure can be obtained between the inside of the guiding sleeve 3 and the drive shaft 25. The sealing rings 24 ensure that the drilling fluid pressure in the guiding sleeve 3 can be maintained without any losses of pressure. A 20 pressure-boosting nozzle 32 has been arranged downstream of the sleeve arrangement 1 enclosing the mouth of the water duct 29 in the region between the rotary core barrel 25 and the outer sleeve device 5, which is non-rotating during drilling. In this way, the water pressure can be increased in the sleeve arrangement 1. The pressure-boosting nozzle 32 can be 25 exchangeable and can be adapted to different conditions. It can also be adjustable on the basis of the prevailing conditions, such as drilling depth, etc. During the actual drilling process, drilling fluid is thus supplied under pressure. This pressurized drilling fluid causes the supporting units 7 to extend in the radial direction against the wall 9 of the bore hole (see Fig. 1). 30 With the aid of, for example, ceramic O-rings 17 arranged on each supporting unit 7 for sealing against the recess 15, the drilling fluid pressure WO 01/02695 PCT/SE00/01395 9 is able to be maintained without any losses. Each supporting unit 7 is provided with protruding elements which provide engagement in the bore hole wall 9 (see Fig. 1). In Figure 2-5, this is shown to consist of at least one protruding tip 13, for example in the form of a prism of tough, hard-wearing 5 material. The prism can be constituted by hard-metal cutters (for example tungsten carbide) or diamond cutters, etc. The whole of the supporting unit, that is to say a supporting unit comprising a protruding element 13 (see Fig. 3), can advantageously be constituted by hard metal, etc. The engagement in the bore hole wall 9 (see Fig. 1) should be tailored such that the friction is 10 low enough to be surmountable in the axial direction by means of downward pressure of the drilling tubes 11 (see Fig. 1) during drilling and high enough to friction-lock against possible rotation under the influence of the drilling tube 11 (see Fig. 1) as this rotates. During drilling, the sleeve arrangement 1 is therefore able to secure, for example, the outer sleeve device 5, which is 15 non-rotating during drilling, to a drilling device, as is described in concurrent Swedish patent application No. 9902544-7, albeit with a different reference notation there. Fig. 3 shows a cross section of the sleeve arrangement 1 in Fig. 2 according 20 to a first illustrative embodiment along the cross-sectional line A-A in Fig. 2. In order to clarify the drawing, a cross section of the supporting units 7, with their respective protruding elements 13 having a tip (with no reference notation), is not however shown. The supporting units 7 are advantageously extended in the bore hole direction according to the drawing, but can have a 25 different configuration. The supporting units 7 are freely slidable inwards and outwards in the guiding sleeve 3. Centrally around the wall of each supporting unit 7, grooves 15 have been arranged for the acceptance of an O ring 17 made from ceramic material. This seal can also be configured as a packing or can have a different form. With the aid of the seal, the drilling 30 fluid pressure is maintained without any loss of drilling fluid which can be used at the cutter head 4. In the figure, a working position is shown. That is WO 01/02695 PCT/SE00/01395 10 to say, when the drilling process is in progress and a drilling fluid pressure is in force. In this working position, the supporting units 7 are pushed out against the rock hole wall 9 (see Fig. 1), the protruding elements 13 arranged on the supporting units 7 engaging in the bore hole wall 9 (see Fig. 1). The 5 protruding elements 13 (only one is illustrated in the figure) can be constituted, for example, by diamond cutters. Rod-shaped elements of different materials or sharp edges can also constitute the protruding elements 13. When the drilling process is discontinued for the raising of drilling samples, etc. or an adjustment of the guide mechanism (not shown) is to take 10 place, the drilling fluid pressure ceases and the supporting units 7 are freely slidable in the recess 15. The guide device described in the concurrent Swedish patent application can advantageously be provided with a sleeve arrangement 1 according to the present invention described in this text. The outer sleeve device 5, which is non-rotating during drilling, can be held in its 15 position by virtue of a certain deviation thereof by means of a guide mechanism 14 (see Fig. 1), which therefore means that the guide mechanism 14 can be held in a fixed position without the sleeve arrangement according to the invention needing to secure the outer sleeve device 5 whilst the core barrel 6 is raised. When the whole of the drilling equipment is raised, the 20 bore hole wall 9 (see Fig. 1), owing to the fact that the supporting units 7 are freed such that they can slide inwards, does not inflict any friction damage upon the diamond cutters. In Fig. 2, those sides of the supporting units 7 which face the bore hole wall 9 (see Fig. 1) are arched outwards with a radius corresponding to the outside of the guiding sleeve 3. In the figure, a 25 cross section of the motion-limiting stop sleeve 20 is also shown in a position between the drive shaft 25 and the guiding sleeve 3. The motion limiting stop sleeve 20 is arranged with both its ends against the sealing rings 24 (see Fig. 2) and is provided with through-holes (not illustrated) transversely to the bore hole direction, so that the drilling fluid pressure can 30 act upon the pressure-absorbing surfaces 7a (illustrated with dashed lines when the supporting units 7 are in folded-in position) belonging to the WO 01/02695 PCT/SE00/01395 11 supporting units 7. The drive shaft 25 is located centrally in the sleeve arrangement 1 and has a certain play therein. Fig. 4 shows an enlarged cross section of the sleeve arrangement 1 in Fig. 2 5 according to a second illustrative embodiment along the cross-sectional line A-A in Fig. 2. However, in order to clarify the drawing, a cross section of the supporting unit 7, with its protruding element 13, is not shown. What distinguishes this illustrative embodiment from the first is that only one supporting unit 7 having a diamond cutter is included in the sleeve 10 arrangement 1. More than one diamond cutter can be arranged on the supporting unit to engage in the bore hole wall 9 during drilling (see Fig. 1). Otherwise, the parts and the sections denoted in the figure correspond to those shown in Fig. 3 and will therefore not be described here any further. What are additionally included in Fig. 4 are the fixedly mounted protruding 15 elements 14. These can be configured and made of the same material as the protruding elements 13 in Fig. 3. In the drilling process, the supporting unit 7a, in a similar manner to the supporting units 7 in Fig. 3, is pushed out against the wall 9 of the bore hole (see Fig. 1) and brings the protruding element 13 into engagement with the bore hole wall 9 (see Fig. 1). The 20 fixedly mounted protruding elements 14 therefore also enter into engagement with the bore hole wall 9 (see Fig. 1) by the actual sleeve arrangement 1 being pressed against the bore hole wall 9 (see Fig. 1) upon the extension of the supporting unit 7a. 25 Fig. 5 shows a top view of one of the supporting units 7 arranged on the sleeve arrangement 1 in Figs 1 to 4. The extensible guide unit 7, 7a is configured with an element 13 which is extended in the longitudinal direction of the bore hole. A sharp tip 40 is expediently made from tough, hard-wearing material, as described above. The length of this tip 40 can 30 vary, depending on the axial pressure on the drill and the torque present there, to obtain perfect guidance of the outer sleeve device 5. Preferably, the WO 01/02695 PCT/SE00/01395 12 length of the extended element 13 measures 10-200 mm, depending on the necessary pressure and type of rock. A flange 60 (illustrated with dashed line) or shoulder is arranged on the inside of the supporting unit 7, 7a to prevent the supporting element 7, 7a from falling out of the sleeve 3 when 5 the sleeve arrangement 1 is transported above ground. The adjustable supporting unit 7, 7a and the protruding element 13 are in the figure extended in the bore hole direction. The supporting unit 7 and the protruding element 13 preferably have an extent of 10-200 mm. For 10 example, the extent can measure 50-100 mm.

Claims

1. Sleeve arrangement (1) for a rock drill, comprising a sleeve (3), which is non-rotating during drilling and is arranged on an outer sleeve device (5), 5 which belongs to the rock drill and is also non-rotating during drilling, which sleeve arrangement, at intervals during the drilling, is subjected to a drilling fluid pressure and will be held in a rotation-proof position with the aid of adjustable supporting units (7), the supporting units (7) being arranged so as to be held against a bore hole wall (9) with a friction which is low enough to 10 be surmountable in the axial direction by means of downward pressure of a drilling tube (11) during drilling and high enough to friction-lock against possible rotation under the influence of the drilling tube (11) as this rotates, characterized in that the sleeve arrangement (1) comprises at least one supporting unit (7, 7a) which is directly acted upon in the radial direction by 15 the drilling fluid and has protruding elements (13) which can engage in a bore hole wall (9) such that the sleeve arrangement (1) is non-rotatable in the peripheral direction in relation to the bore hole wall (9), and the at least one supporting unit (7) is arranged in a corresponding recess (15) located in the sleeve (3). 20

2. Sleeve arrangement according to Claim 1, characterized in that the supporting unit (7), in the absence of drilling fluid pressure, is freely slidable in the recess (15) of the sleeve arrangement. 25

3. Sleeve arrangement according to Claim 1, characterized in that a heat resistant sealing device (17) is arranged between the supporting unit (7) and the recess (15).

4. Sleeve arrangement according to Claim 3, characterized in that the 30 sealing device (17) is constituted by a sealing ring made from heat-resistant material, for example ceramic material, which sealing ring is arranged in a WO 01/02695 PCT/SE00/01395 14 corresponding groove on that side of the supporting unit (7) facing the recess (15).

5. Sleeve arrangement according to any of the preceding claims, 5 characterized in that the at least one adjustable supporting unit (7) and the protruding element (13) are extended in the bore hole direction.

6. Sleeve arrangement according to Claim 5, characterized in that the at least one adjustable supporting unit (7) and the protruding element (13) preferably have an extent of 10-200 mm, preferably 50-100 mm. 10

7. Sleeve arrangement according to any of the preceding claims, characterized in that the sleeve arrangement (1) comprises only one adjustable supporting unit (7a) with the protruding element (13) and in that the sleeve arrangement (1) comprises at least one fixed-mounted protruding 15 element (14).

8. Sleeve arrangement according to any of the preceding claims, characterized in that the sleeve arrangement (1) is connected in a fixable manner to the outer sleeve device (5), which is non-rotating during drilling. 20

9. Sleeve arrangement according to any of the preceding claims, characterized in that the sleeve arrangement (1) is arranged in an upper position on the outer sleeve device (5), viewed in the direction downwards from the ground surface (min), which outer sleeve device (5), in a lower 25 position, is laterally displaceable in respect of its centre or is articulated in order to achieve a guidance of the rock drill.