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WO2012051648A1 - Foret - Google Patents

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Publication number
WO2012051648A1
WO2012051648A1 PCT/AU2011/001325 AU2011001325W WO2012051648A1 WO 2012051648 A1 WO2012051648 A1 WO 2012051648A1 AU 2011001325 W AU2011001325 W AU 2011001325W WO 2012051648 A1 WO2012051648 A1 WO 2012051648A1
Authority
WO
WIPO (PCT)
Prior art keywords
drill bit
fluid flow
fluid
working end
flow passage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/AU2011/001325
Other languages
English (en)
Inventor
Brian Thomas Sanfead
Rober Gordon Brand Walters
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Drilling Tools Australia Pty Ltd
Original Assignee
Drilling Tools Australia Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2010904648A external-priority patent/AU2010904648A0/en
Application filed by Drilling Tools Australia Pty Ltd filed Critical Drilling Tools Australia Pty Ltd
Priority to AU2011318230A priority Critical patent/AU2011318230A1/en
Publication of WO2012051648A1 publication Critical patent/WO2012051648A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/60—Drill bits characterised by conduits or nozzles for drilling fluids
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/62—Drill bits characterised by parts, e.g. cutting elements, which are detachable or adjustable
    • E21B10/627—Drill bits characterised by parts, e.g. cutting elements, which are detachable or adjustable with plural detachable cutting elements
    • E21B10/633—Drill bits characterised by parts, e.g. cutting elements, which are detachable or adjustable with plural detachable cutting elements independently detachable
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/62—Drill bits characterised by parts, e.g. cutting elements, which are detachable or adjustable
    • E21B10/627—Drill bits characterised by parts, e.g. cutting elements, which are detachable or adjustable with plural detachable cutting elements

Definitions

  • This invention relates to drill bits.
  • a problem which occurs frequently in drilling operations is management of drilling through soft and viscous material formations such as clay, mud or other material which may include grit and such like.
  • Most drills include a hollow stem portion and one or more passages through the drill bit providing for the delivery of air or other fluid, including liquids, to the working face of a hole to cool the bit and flush debris from the hole.
  • air or other fluid including liquids
  • the relatively small diameter passages provided in most drill bits tend to clog with mud and debris limiting drilling speed (as referenced in US 5735360).
  • a drill bit which is configured with a plurality of radially disposed "wings" extending from a conical centre body.
  • wings Such a winged bit design, which is suitable for drilling of softer formations (such as coal seams) is distinct from drill bits used in reverse circulation (“RC") drilling which are typically used for hard rock drilling.
  • Conventional designs of RC drill bits therefore do not comprise such wings, which would likely be quickly destroyed in service.
  • Each wing is provided with sockets, having cutting teeth, called picks, disposed in them.
  • the pick sockets have different spacing along each wing so that the central teeth along each wing are cutting along different paths, as the drill bit is rotated, for greater efficiency.
  • This relatively large passage allows a greater flow of air and/or liquid coolant and/or lubricant therethrough, the aim being to allow a more rapid advance of the drill bit with less clogging with soft drill cuttings during drilling.
  • the relatively large passage is centrally located in the body of the bit and provides a non-directional exhaust portal or opening through which fluid flows without any particular direction.
  • a drill bit may be 'buried' to some extent in a relatively soft formation, such as a coal seam, during the drilling operation, causing rapid wear on the picks.
  • Such wear may be experienced at the tip or leading cutting edge of the wings but abrasion also occurs on portion(s) of cutting teeth rotating in the above mentioned sockets due to the presence of grit between the mating surfaces.
  • the present invention provides a drill bit comprising:
  • a body having a drill stem attachment end and a working end opposite the attachment end;
  • said means for conveying fluid comprises a plurality of fluid flow passages for directing fluid towards the working end of the drill bit, each fluid flow passage directing fluid in a selected direction.
  • the working fluid is the fluid used to operate a drilling apparatus comprising the drill bit and is typically compressed air supplied by a suitably sized air compressor included in a drill rig in which the drill bit is used.
  • Each fluid flow passage is advantageously oriented, that is directed at an angle to direct fluid through respective discharge ports for each fluid flow passage towards zones - for example close to the cutting edges of the drill bit - where grit, clay, mud and other material, particularly soft viscous material may collect, adversely impacting on drilling operations.
  • Different fluid flow passages in the same drill bit may be oriented toward different zones including the centre of the working end of the drill bit or the periphery of the working end of the drill bit. It is most advantageous for one or more of the fluid flow passages to be oriented at an angle towards the centre of the working end of the drill bit and one or more of the fluid flow passages to be oriented at an angle towards the periphery of the working end of the drill bit.
  • the number of fluid flow passages may, without this being essential, correspond with the number of planar wings provided in the drill bit. For example, where four planar wings are provided, four fluid flow passages may be provided, such arrangement allowing for zones located between each of the wings to be flushed with the working fluid.
  • planar wings may be mechanically fixed to the drill bit body.
  • planar wings or wing plates are located in, or mechanically keyed to, the drill bit body in recesses provided for the purpose. Final fixing may be by welding.
  • a number of wing plates may be fixed to the drill bit body. However, a stronger drill bit design may be achieved by minimizing the number of wing plates and including an assembly of wing plates, for example an assembly of interlocking wing plates.
  • Use of keying is advantageous from the perspective of drill bit strength and durability and it reduces the frequency of repair or replacement of the drill bit in service.
  • wing plates are interlocked and keyed to the drill bit body in recesses provided for the purpose.
  • Interlocking of wing plates may take place following keying of one wing plate into position on the drill bit body. Final locking of wing plates into position on the drill bit body may involve welding in addition to keying. For example, four individual wing plates could be replaced with two interlocking wing plates providing four distinct planar wing portions.
  • a holder termed a crown block
  • a typically less durable construction in which individual picks are held in individual sockets is advantageously avoided.
  • the crown block typically one being correspondent to each planar wing of the drill bit, may be fixed to the drill bit, and more particularly a planar wing thereof by keying, welding, other techniques or a combination of these techniques. Such a construction is more durable in service. It follows that the planar wings are not provided with cutter elements along all of their outward surfaces and it may be possible to exclude use of abrasion elements over the entire outer surfaces of the wings as well.
  • Each fluid flow passage most advantageously includes a nozzle or restrictor which will provide increased pressure (particularly above fluid pressure in the primary fluid passage if the fluid flow passages are supplied with fluid from this primary fluid passage) of fluid discharged through a discharge port provided for each fluid flow passage.
  • nozzles and restrictors such as orifice plates, have size and working fluid discharge pressure selected to provide a fluid pressure that is sufficient to avoid or significantly reduce clogging, or bogging of the drill bit, under expected drilling conditions. This assists to minimize inconvenient and potentially costly clogging of drill bits by direction of sufficiently high pressure fluid to remove debris and formation material causing such clogging.
  • Jet nozzles are particularly useful for inclusion in the fluid flow passage(s).
  • the nozzle or restrictor is to be located at or proximate the discharge port of each fluid flow passage.
  • a nozzle is to be oriented toward a zone such as the centre of the working end of the drill bit (centre zone) or the periphery of the working end of the drill bit (periphery zone) where risk of clogging occurs.
  • the drill bit has a plurality of fluid flow passages, conveniently diverging from the primary fluid passage, at least one fluid flow passage and its associated nozzle or restrictor will be oriented at an angle towards the centre zone and at least one passage and its associated nozzle or restrictor will be oriented at an angle towards the periphery zone.
  • Nozzles are preferably recessed a distance, or set back, within fluid flow passages but otherwise nozzles, preferably such as jet nozzles, may be fitted into a fluid flow passage in any convenient manner for example interference fitting. Snap rings, O-rings or circlips may also be used for fixing or locking nozzles into position. Such connections may also allow for quick and efficient field replacement of nozzles to increase drilling efficiencies.
  • a fluid flow passage is conveniently cylindrical/circular cross-section in shape.
  • the fluid flow passage may have cylindrical/circular cross section towards its discharge port end.
  • a convenient form of nozzle such as a jet nozzle, therefore has a cylindrical body and an internal bore suitably configured to increase pressure of working fluid as it passes through the internal bore.
  • the internal bore is designed to obstruct or throttle fluid flow passing towards the discharge port.
  • a preferred internal bore has an inward tapering portion, reducing the cross-sectional area of the fluid flow passage in a gradual manner, before terminating in a cylindrical discharge passage or port.
  • the tapering portion may have constant slope or may have an inwardly curving or cusp-like shape.
  • Orifice size or dimension for a nozzle is advantageously selected to optimize working fluid discharge pressure with reference to parameters including working fluid compressor capacity and nature of the formation to be drilled.
  • Nozzles and restrictors may be used in combination to ensure that the fluid pressure in the fluid flow passages is sufficient to avoid or minimize clogging.
  • Restrictor(s) may also be located in the primary fluid passage of the drill bit to achieve the same object.
  • the discharge ports are set back or located a distance away from the working end of the drill bit and not at the bit or cutting face itself. This distance is to be sufficient, without wishing to be bound by any theory, to allow a higher velocity, and greater cleaning effect, as working fluid exhausted from the discharge ports expands to a lower pressure within the bore hole. This pressure may be atmospheric pressure.
  • the setting back of the discharge ports from the cutting edges reduces the probability of clogging with formation solids. This probability further decreases with decreasing acute angle for arrangement of the cutting edges to a longitudinal axis of the drill bit.
  • Each fluid flow passage is conveniently supplied with pressurized working fluid from a primary fluid passage extending through the body of the drill bit.
  • the fluid is the working fluid for a drilling apparatus including the drill bit and is typically compressed air.
  • the fluid flow passages may diverge from a primary fluid passage extending through part of the length of the drill bit.
  • each fluid flow passage may extend towards the working end of the drill bit at an acute angle to an axis of the primary fluid passage, this angle being selected to flush the working end of the bit to minimize clogging and wear.
  • the axis of the primary fluid passage is also an axis, typically the central axis, of the drill bit.
  • the diameter of fluid flow passage(s) will typically be less than the diameter of the primary fluid passage.
  • the primary fluid passage is desirably to be located centrally of the body, perhaps co-axial with an axis of the body.
  • the primary fluid passage may have a terminal wall towards the working end of the drill bit with fluid flow passage(s) diverging, through aperture(s) formed in the terminal wall, from the primary fluid passage towards the working end of the drill bit body.
  • the drill bit may be described as a claw bit.
  • An advantageous design of drill bit has the planar wings extending radially outwardly at an acute angle to an axis of the drill bit in contrast to other drill bits in which the planar wings have edges parallel to a longitudinal axis of the drill bit.
  • Drill bits may be used in vertical and angled drilling applications. The selected acute angle is greater for an angled drilling application of the drill bit than a vertical drilling application. It may be possible, however, to select an acute angle which is suitable for both vertical and angled drilling applications. A preferred such angle would be in the range 50 to 70 degrees, with a most preferred angle being about 60 degrees.
  • the planar wings may extend beyond a truncated conical portion of the body of the drill bit, this conical portion having a base wall extending transverse to a longitudinal axis of the drill bit and side walls convergent towards the base wall.
  • the discharge ports for the fluid flow passages are formed in the truncated conical portion.
  • the discharge ports are formed either in a side wall of the truncated conical portion in the case of a fluid flow passage oriented towards the periphery zone of the working end of the drill bit or in the base wall of the truncated conical portion in the case of a fluid flow passage oriented towards the centre zone of the working end of the drill bit.
  • the body of the drill bit has a generally cylindrical portion with a planar base wall.
  • Fig. 1 is a perspective view of an earth boring bit according to the prior art.
  • Fig. 2 is a top perspective view of a drill bit in accordance with one embodiment of the present invention.
  • Fig. 3 is a bottom perspective view of a drill bit in accordance with one embodiment of the present invention.
  • Fig. 4 is a view of the drill bit of one embodiment of the present invention from its working end and shown in Figs. 2 and 3 of the drawings.
  • Fig. 5 is a side view of a drill bit in accordance with one embodiment of the present invention as shown in Figs. 2 to 4 of the drawings.
  • Fig. 6 is a view of the drill bit from its bottom end as shown in Figs. 2 to 5 of the drawings and without the fixturing/mounting of the cutting edges.
  • Fig. 6a is a side view of a drill bit in accordance with a further embodiment of the present invention.
  • Fig. 6b is a view of the drill bit of Fig. 6a from its bottom end.
  • Fig. 6c is a top view, on a reduced scale, of the drill bit of Figs. 6a and 6b.
  • Fig. 6d is a side view of a drill bit in accordance with a second further embodiment of the present invention.
  • Fig. 6e is a view of the drill bit of Fig. 6c from its bottom end.
  • Fig. 6f is a top view, on a reduced scale, of the drill bit of Figs. 6d and 6e.
  • Fig. 7 is a part sectional view of the drill bit as shown in Figs. 2 to 6 of the drawings and taken along a first section line to show the bit body and primary fluid passage.
  • Fig. 8 is a part sectional view of the drill bit as shown in Fig. 7 of the drawings and taken along a second section line to show bit body and divergent fluid flow passages disposed at a first angle.
  • Fig. 9 is a part sectional view of the drill bit as shown in Figs. 7 and 8 of the drawings and taken along a third section line to show bit body and divergent fluid flow passages disposed at a second angle.
  • Fig. 10 is a detailed section view of a fluid flow passage with jet nozzle showing the seating arrangement.
  • Fig. 1 1 is a detailed section view of the fluid flow passage of Fig.10 without jet nozzle showing the seating arrangement.
  • Fig. 12 is a view from a working end of one jet nozzle which may be used in the drill bit shown in Figs. 2 to 1 1 .
  • Fig. 13 is a view of the jet nozzle of Fig. 12 taken from its other end.
  • Fig. 14a shows a first interlockable wing plate for use in a drill bit in accordance with a further embodiment of the present invention.
  • Fig. 14b shows a second interlockable wing plate, for interlocking with the wing plate of Fig. 14a, for use in the drill bit of the further embodiment of the present invention.
  • Fig. 15a shows an end view of two wing plates assembled by interlocking.
  • Fig. 15b shows a side view of two wing plates prior to assembly.
  • Figs. 15c and 15d show isometric views of two interlockable wing plates prior to assembly.
  • Fig. 15e shows a further isometric view of two interlockable wing plates prior to assembly.
  • Fig. 15f shows a first isometric view of the two wing plates after assembly.
  • Fig. 15g shows a top view of the two wing plates after assembly.
  • Fig. 15h shows a side view of the two wing plates after assembly.
  • Fig. 15i shows a second isometric view of the two wing plates after assembly.
  • Fig. 15j shows a third isometric view of the two wing plates after assembly.
  • Fig. 1 6 shows an isometric view of a drill bit prior to assembly of the wing plates.
  • Fig. 17 shows an isometric view of the drill bit of Fig. 16 after assembly of the wing plates.
  • Fig. 18a shows an exploded isometric view of the drill bit of Fig. 16 showing the jet nozzles included within the drill bit.
  • Fig. 18b shows a detail of Fig. 18 showing a jet nozzle included within the drill bit.
  • Fig. 19 shows a bottom view of the drill bit of Figs 17, 18a and 18b.
  • Fig. 20 shows a section view taken along section line D-D of the drill bit as shown in Fig. 19.
  • Fig. 21 shows a detail section view of a discharge port included in Fig. 20, the discharge port having a jet nozzle with orifice size A.
  • Fig. 22 shows a detail section view of a discharge port with an alternative jet nozzle with orifice size B for use in the discharge port shown in Figs. 20 and 21 .
  • Fig 23 shows an exploded bottom view of the drill bit of Fig. 19 showing the jet nozzles included within the drill bit.
  • Fig. 24 is an exploded section view taken along section line E-E of the drill bit as shown in Fig. 23.
  • Fig. 25 shows a detail exploded section view of a discharge port and its associated jet nozzle.
  • Fig. 26a is a top view of a holder, in the form of a crown block, for four picks for a planar wing of the drill bit.
  • Fig. 26b is a left side view of the crown block of Fig. 26a.
  • Fig. 26c is a front view of the crown block of Figs. 26a and 26b.
  • Fig. 26d is a right side view of the crown block of Figs. 26a to 26c.
  • Fig. 26e is a bottom view of the crown block of Figs. 26a to 26d.
  • Fig. 26f is an isometric view of the crown block of Figs. 26a to 26e.
  • Fig. 26g is an isometric view of the crown block of Fig 26f and taken from the opposite side of Fig. 26f.
  • Fig. 27a is a top view of a holder, in the form of a crown block, for three picks for a planar wing of the drill bit.
  • Fig. 27b is a left side view of the crown block of Fig. 27a.
  • Fig. 27c is a front view of the crown block of Figs. 27a and 27b.
  • Fig. 27d is a right side view of the crown block of Figs. 27a to 27c.
  • Fig. 27e is a bottom view of the crown block of Figs. 27a to 27d.
  • Fig. 27f is an isometric view of the crown block of Figs. 27a to 27e.
  • Fig. 27g is an isometric view of the crown block of Fig 27f and taken from the opposite side of Fig. 27f.
  • Figs. 28a and 28b are two respective isometric views of the crown block of Figs. 26a to 26f showing a pick located within one of its four pick sockets.
  • Fig. 29a is a view illustrating a pick and crown block pre-assembly.
  • Fig. 29b is a section view taken along section A-A of Fig. 29a.
  • Fig. 29c is a detail section view B taken from Fig. 29b.
  • Fig. 30a is a view illustrating a pick and crown block pre-assembly.
  • Fig. 30b is a section view taken along section A-A of Fig. 30a.
  • Fig. 30c is a detail section view B taken from Fig. 30b.
  • FIG. 1 there is shown a perspective view of an earth boring bit 10 - as described in WO 2008/069863 - having relatively steeply angled cutting faces so that the apex 32 of the bit 10 makes initial contact with the surface and/or any underlying hard strata when the bit 10 is driven at other than a vertical angle to the surface or strata S.
  • the bit 10 includes a truncated, generally conical body portion 12 having a relatively wide base 14 and a relatively narrow working end 16 opposite the base 14.
  • a drill stem attachment end 18 extends from the base 14, with the drill stem attachment end 18 including a tapered, externally threaded portion 20 for removable attachment to a drill stem.
  • a series of radially disposed cutting faces or wings 22 extend outwardly from the conical body portion 12. Each of the faces has a working or leading edge 24. with each of the edges 24 forming an acute angle relative to the axial centerline of the bit 10.
  • Each working or cutting edge 24 includes a series of separate cutting tooth or pick sockets 26 disposed along the working edge 24 of each wing 22.
  • a pick 28 is removably and individually installed in each of the sockets 26. The picks 28 may be punched or pressed out of the sockets 26 when worn or broken, with new replacement picks being pressed into the sockets 26 as needed.
  • the provision of separate pick sockets 26 provides a weak point in drill bit 10 and failure may occur too frequently at the pick sockets 26. Such failure is disruptive to drilling operations and has an undesirable cost.
  • Earth boring bit 10 includes a single fluid passage extending axially through the body portion 12 and threaded portion 20 for conveying fluid from the hollow drill stem through the bit 10 to flush debris from the hole being drilled during drilling operations.
  • the working fluid compressed air supplied from a compressor, is discharged through a single opening 16a at the working end 16 of bit 10.
  • the opening 16a is centrally located at the apex 32 of body portion 12 of the bit 10 and provides a non-directional exhaust portal or opening through which compressed air flows without any particular direction.
  • bit 10 tends to be 'buried' or bogged to some extent in a formation during the drilling operation, causing rapid wear on the picks 28.
  • Such wear is particularly experienced at the tip or leading cutting edges 24 of the wings but also on portion(s) of cutting teeth rotating in the above mentioned sockets due to the presence of grit between the mating surfaces.
  • a drill bit 1 10 which may be termed a claw bit, comprising a body 1 12.
  • the body 1 12 includes a drill stem attachment end 1 18 and a working end 1 16.
  • the drill stem attachment end 1 18 includes a tapered, externally threaded portion 120 for removable attachment to a drill stem (not shown).
  • the body 1 12 of drill bit 1 10 has a series of planar wings 122 fixed to body 1 12.
  • the planar wings 122 are mechanically keyed to body 1 12, in recesses or grooves provided for the purpose, and then welded to it. This use of keying and welding provides a stronger construction less subject to damage than the earth boring bits of the prior art.
  • the planar wings 122 extend beyond a truncated conical portion 1 13 of the body 1 12 of drill bit 1 10 as conveniently shown in Figs. 2, 3 and 5.
  • This conical portion 1 13 has a base wall 1 14 extending transverse to a longitudinal axis L of the drill bit 1 10 and side walls 1 15 convergent towards the base wall 1 14. Side walls 1 15 face in the direction of a periphery of the working end 1 16 of the drill bit 1 10.
  • Base wall 1 14 faces downward toward the centre of the working end 1 16 of drill bit 1 10.
  • the working end 1 16 of drill bit 1 10, disposed about planar wings 122, is relatively wide in comparison with the drill stem attachment end 1 18 due to series of four radially disposed wings 122 extending radially outwardly at an acute angle to the longitudinal axis L of the drill bit 1 10 from the body 1 12.
  • the wings 122 are otherwise planar in geometry as this assists cutting action.
  • Each of the wings 122 has, fixed to it, an angled, slightly serrated, cutting or leading edge or crown block 124, each including a series of cutting tooth or pick sockets 126 within a single block.
  • the crown block 124 is treated, for example by hardening, to provide required strength and durability.
  • crown blocks 124 avoids need for picks to be directly fixed into the planar wings 122. During use of drill bit 1 10, wear is likely to occur on the crown blocks 124 but it is easier, and less costly to replace a crown block 124, if required, than a planar wing 122 of the drill bit 1 10. Crown blocks 124 may also be made of strongly wear resistant material to reduce wear.
  • Crown blocks 124 which are illustrated throughout Figs. 2 to 6f and further in Figs. 26a to 30c may be welded, mechanically fixed or keyed (for example by dovetailing or square keying) to each planar wing 122 at surface 124a as shown in Figs. 26f and 27f in a manner allowing flexibility for re-adjustment and replacement as a drilling operation proceeds.
  • Crown blocks 124 are modular and different forms of crown block 124 may be used for different drilling applications and formations.
  • Picks 128 are fitted into the pick sockets 126 of crown blocks 124 in the following manner.
  • Sleeves 127 of hardened steel or tungsten carbide, are first press fitted or shrink fitted (with the assistance of a liquefied gas such as nitrogen) of sleeves 127 into the pick sockets 126 of each crown block 124 as shown in the pre-assembly state shown in Figs. 29a to 29c.
  • Picks 128 are then located within the sleeves 127, being seated in facets 126b, in the manner as shown in Figs. 30a to 30c with illustrative isometric views being provided as Figs. 28a and 28b.
  • the pick 128 shown in the drawings is located towards the longitudinal axis, L, of the drill bit 1 10 and is, in this sense, the innermost pick located on crown block 124.
  • the gauge pick 128a or the pick located outermost on the crown block 124 is located in pick socket 1260. Four such gauge picks 128a are shown in the drawing. Gauge picks 128a are located radially outward of planar wings 122, as especially conveniently seen in Fig. 6f.
  • Picks 128 are relatively elongated, in comparison with a button construction, and have conical geometry at their tips 129 and are, as with sleeves 127, of tungsten carbide or hardened steel. Picks 128 are located within the sleeves 127, being seated on facets 126b, in a manner allowing them to rotate during operation of the drill bit 1 10.
  • Picks 128 may be located within sleeves 127 and removed from them in straightforward operations. Removal is assisted by the pick sockets 126 extending through the crown block 124 to openings 126a allowing for the picks 128 to be punched out of the pick sockets 126 when required for maintenance or other purposes.
  • crown blocks 124 are provided with three picks 128 and two of the crown blocks 124 are provided with four picks 128. It is not essential that each crown block 124 used in drill bit 1 10 have the same number of picks 128 located within them. Indeed, use of crown blocks 124 with differing number of picks 128 may facilitate assembly of the drill bit 1 10.
  • the differing crown blocks 124 for four picks 128 and three picks 128 are shown in Figs 26a to 24g and 27a to 27g respectively.
  • Wings 122 may be arranged in an angled or vertical configuration as shown in Figs. 6a to 6c (angled) and Figs. 5, 6, 6d to 6f (vertical). In the angled configuration, wings 122 have a lesser acute angle to the longitudinal axis, L, of the drill bit 1 10 than for the vertical configuration. In addition, the base wall 1 14 is located at a greater distance D, from the leading cutting picks 128d for the angled configuration, than the corresponding distance F for the vertical configuration. It may be noted that the drill bit body portion 1 13 of the drill bit 1 10 shown in Figs. 6a to 6d is generally cylindrical and not in the shape of a truncated cone.
  • Drill bit 1 10 includes a means for conveying working fluid through it and towards the working end 1 16 comprising a primary fluid passage 130 and fluid flow passages 136a, 136b opening through discharge ports 137. Fluid flow passages 136a, 136b diverge at respective angles A and B from the primary fluid passage 130 extending part of the length of the drill bit 1 10 as shown in Figs. 8 to 1 1 . Selection and function of angles A and B is described below.
  • the working fluid used to operate the drilling apparatus comprising the drill bit 1 10 is compressed air supplied by a suitably sized air compressor.
  • Each fluid flow passage 136a, 136b is oriented, that is directed at an angle to direct fluid through discharge ports 137 towards zones - for example close to the planar wings 122 and cutting edges 124 - where grit, clay, mud and other material, particularly soft viscous material could collect, adversely impacting on drilling operations through clogging. There are four such zones located in the spaces between the planar wings 122.
  • the fluid flow passages 136a, 136b are supplied with compressed air from primary fluid passage 130.
  • Primary fluid passage 130 has a terminal wall 132 towards the working end of the drill bit 1 10 with fluid flow passages 136a diverging, through apertures 134 formed in the terminal wall 132, from the primary fluid passage 130 towards the working end 1 16 of the drill bit body 1 12 (as conveniently shown in Figs. 7 to 9).
  • Apertures 134 are of ovoid shape contrasting with the generally cylindrical geometry of the fluid flow passages 136a, 136b.
  • Fluid flow passages 136 in the drill bit 1 10 are oriented at angles towards zones including the periphery of the working end 1 16 of the drill bit 1 10 and the centre of the working end 1 16 of the drill bit 1 10.
  • One pair of fluid flow passages 136a as shown in Figs. 2, 4, 6, 8, 10 and 1 1 diverge from primary fluid passage 130 at an angle A, an angle selected to ensure compressed air flow, in direction A, towards the periphery of the working end 1 16 of drill bit 1 10.
  • Fluid flow passages 136a discharge through discharge ports 137 formed in beveled side walls 1 15 of the truncated conical portion 1 13 of body 1 12 of the drill bit 1 10.
  • the other pair of fluid flow passages 136b as shown in Figs.
  • Fluid flow passages 136b discharge through discharge ports 137 formed in the base wall 1 14 of the truncated conical portion 1 13 of body 1 12 of the drill bit 1 10.
  • all discharge ports 137 are located in the planar base wall 1 14.
  • discharge ports 137 will be sufficient to achieve the desired cleaning effect.
  • Each fluid flow passage 136a, 136b includes a nozzle 160, recessed or set back within each flow passage 136a, 136b, to provide increased fluid pressure over pressure in the primary fluid passage 130 supplying working fluid to those fluid flow passages 136a, 136b.
  • the increased working fluid pressure achieved by location and design of the nozzles 160, is sufficient to avoid or significantly reduce clogging under expected drilling conditions thus assisting to minimize inconvenient and potentially costly clogging of drill bits by direction of sufficiently high pressure fluid to remove debris and formation material causing such clogging.
  • Jet nozzles are selected for the nozzles 160 of fluid flow passages 136a, 136b.
  • Each jet nozzle 160 is located at a position set back or recessed from the discharge port 137 of each fluid flow passage 136a, 136b as shown in Figs. 2 to 4, 6 and 7 to 10. Jet nozzles 160 are oriented with centre axis toward a zone being the periphery of the working end 1 16 of the drill bit 1 10 (periphery zone) or the periphery of the working end of the drill bit (centre zone) dependent on whether a jet nozzle 160 is located in fluid flow passage 136a or 136b. Recesses 164 are illustrated in a number of the drawings.
  • Each fluid flow passage 136a, 136b is conveniently cylindrical and has circular cross section towards its discharge port 137 end.
  • Jet nozzles 160 as most conveniently illustrated in Figs. 10 to 13, therefore conveniently have a cylindrical body 163 and an internal bore 166 suitably configured to increase pressure of working fluid as it passes through the internal bore 166.
  • the internal bore 166 is designed to obstruct or throttle fluid flow passing towards each discharge port 137.
  • internal bore 166 has an inward tapering portion 168, reducing the cross-sectional area of the fluid flow passage in a gradual manner, before terminating in a cylindrical discharge passage 169.
  • the tapering portion 168 has an inwardly curving or cusp-like shape. The degree of curvature of tapering portion 168 may be selected to achieve the desired increase in working fluid pressure.
  • Jet nozzles 160 are press fitted into fluid flow passages 136a, 136b and snap rings and/or O-ring components are conveniently used to make such fitting secure as schematically illustrated in Figs. 10 and 1 1 .
  • O-ring or snap ring 162 is fitted into groove 161 following press fitting of the jet nozzle 160 to make the connection.
  • Jet nozzles 160 and restrictor 170 are used in combination to ensure that the fluid pressure in the fluid flow passages 130, 136a, 136b is sufficient to avoid or minimize clogging.
  • orifice plate 170 having opening 171 with diameter less than the inner diameter of primary fluid passage 130 is fitted at the drill stem attachment end 1 18 of drill bit 1 10. This throttles compressed air flow through the primary fluid passage 130 and assists with increasing pressure and velocity of compressed air passing through the drill bit 1 10. This, in turn, reduces clogging and wear of the cutting edges 124 of the drill bit 1 10.
  • a washer 171 is fitted at the drill stem attachment end 1 18 of drill bit 1 10 to assist sealing and maintenance of required compressed air flow pressure through the drill bit 1 10 when connected to a drilling apparatus.
  • Figs 14a to 25 there is shown a further embodiment of the drill bit in which the planar wings, provided with formation cutting faces, are formed by an assembly of interlocking wing plates 220 and 222.
  • Wing plate 220 as shown in Fig. 14a and clearly of planar design, is provided with a slot 221 and angled portions 225 generally configured in the shape of a truncated triangle with rounded apices and approximating the profile of the working end 216 of the drill bit body 212. Wing plate 220 is also provided with a beveled portion 219 on which picks (not shown) are to be located, the picks being provided in a crown piece (also not shown).
  • Wing plate 222 is of complementary design to wing plate 220, having a slot 223 for engaging with the slot 221 and also having a beveled portion 224 and angled portions 225.
  • wing plates 220 and 222 are provided for engaging or 'keying' with grooves or recesses formed about the periphery of the body 212 of drill bit 210 as shown in Figs. 16 and 17.
  • Figs. 15a to 15e indicate how the wing plates 220 and 222 are interlocked together by keying to form a single wing plate assembly, the wing plate assembly having four distinct planar wing portions 227.
  • Wing plates 220 and 222 are moved into a position in which slots 221 and 223 are in alignment.
  • Wing plate 220 is then slid or pressed over wing plate 222 until the slot portions 221 a and 223a engage. At that point, the wing plates 220 and 222 are interlocked and the wing plate assembly is complete, as shown in Figs. 15f to 15j, bar welding to lock the wing plates 220 and 222 together.
  • wing plate assembly could be made prior to connection to the body of a drill bit.
  • wing plate 222 may first be keyed into grooves 226, adapted to receive the angled portions 225 of that wing plate 222.
  • grooves 226 have a complementary profile to the angled portions 225 of wing plate 222. Welding then follows to lock wing plate 222 into position on the body 212 of drill bit 210. This results in a stronger construction than if keying was not adopted.
  • Wing plate 220 may then be assembled, by interlocking, to wing plate 222 in essentially the same manner as above described.
  • angled portions 225 of wing plate 220 are keyed, for purposes of enhanced strength over other constructions, into grooves 226 which are adapted to receive these angled portions 225.
  • the finished drill bit 210 is shown in Fig. 17.
  • Figs. 18a to 25 show drill bit 210 with the interlocking wing plate assembly and with jet nozzles 260 fitted in discharge ports 237 of fluid flow passages 236, four of which are provided.
  • Each discharge port 237 is located in a quadrant 229 of a base wall 214 of the drill bit body 212 formed by the assembly of interlocking wing plates 220 and 222.
  • Base wall 214 extends perpendicular to axis N of drill bit 210 and has greater area than base wall 1 14 of drill bit 1 10 and the body 212 is of generally cylindrical shape with a beveled portion at the transition with base wall 214, a difference in shape from the truncated conical portion 1 13 for drill bit 1 10.
  • Each discharge port 237 discharges pressurized working fluid, compressed air, at an acute angle to the longitudinal axis N of drill bit 210. Again, the compressed air is directed towards zones where clay, grit, mud and other material, particularly soft viscous material could collect, adversely impacting on drilling operations through clogging.
  • the location of each discharge port 237, in the corner 231 of each correspondent quadrant 229 is selected to promote this cleaning effect. Airflow direction in the drill bit 210 is shown by the airflow direction arrows in Figs. 20 to 22.
  • fluid flow passages 236 are supplied with compressed air from primary fluid passage 230.
  • Primary fluid passage 230 has a concave terminal wall 232 towards the working end 216 of drill bit 210 with fluid passages 236 diverging, through apertures 234 formed in the terminal wall 232, towards the working end 216.
  • Apertures 234 are of ovoid shape and greater cross sectional area than other portions of the generally cylindrical fluid flow passages 236.
  • Jet nozzles 260 have a cylindrical body 263, the cylindrical shape allowing ready accommodation at the discharge port 237 end of each fluid flow passage 236.
  • the internal bore 266 is suitably configured to increase compressed air pressure as it passes through the internal bore 266.
  • the internal bore 266 is designed to obstruct or throttle compressed air passing towards each discharge port 237.
  • jet nozzles 260 have an inward tapering portion 268, reducing the flow cross-sectional area in a gradual manner before terminating in a cylindrical discharge portion 266 having orifice size indicated by dimension A in Fig. 21 .
  • the transition is more gradual than for jet nozzles 160 (and no cusp portion is included, the transition is more linear). This selection of jet nozzle design results from a selection process taking into account air compressor capacity and nature of the formation to be drilled.
  • Fig. 22 indicates a further jet nozzle 260a which is available to replace jet nozzles 260 as required.
  • Jet nozzle 260a has a similar design to jet nozzles 160. However, the orifice size has a dimension B less than dimension A for jet nozzles 260 and this design would allow higher compressed air discharge pressures and a higher working end 216 cleaning effect to be achieved.
  • Jet nozzles 260, 260a are press fitted into fluid flow passages 236 at their discharge port 237 ends.
  • Circlips 262 located within grooves 261 of the cylindrical bodies 263 of jet nozzles 260, are conveniently used to make such fitting secure as schematically illustrated in Figs. 23 to 25.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)

Abstract

La présente invention concerne un foret (110) comprenant : (a) un corps (112) comportant une extrémité de fixation d'allonge de foret et une extrémité de travail opposée à l'extrémité de fixation ; (b) des moyens (130, 136a, 136b), permettant d'acheminer un fluide de travail, s'étendant à travers le corps (112) ; (c) une pluralité d'ailes planes (122) raccordées au corps (112) et pourvues de tranchants (124) s'étendant depuis le corps (112) ; et (d) une extrémité de travail (116) disposée autour des tranchants (124) des ailes planes (122). Les moyens (130, 136a, 136b) permettant d'acheminer un fluide comprennent une pluralité de passages d'écoulement de fluide (136a, 136b) permettant de diriger un fluide vers l'extrémité de travail (116) du foret (110), chaque passage d'écoulement de fluide (136a, 136b) dirigeant le fluide dans une direction sélectionnée. Les ailes planes (122) sont avantageusement fixées mécaniquement au corps de foret (112), des plaques d'aile (122) étant placées dans le corps de foret (110) dans des évidements (226) et fixées par clavetage mécanique audit corps par une fixation finale qui se fait par soudage.
PCT/AU2011/001325 2010-10-19 2011-10-19 Foret Ceased WO2012051648A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2011318230A AU2011318230A1 (en) 2010-10-19 2011-10-19 A drill bit

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AU2010904648 2010-10-19
AU2010904648A AU2010904648A0 (en) 2010-10-19 A drill bit
AU2011900950 2011-03-17
AU2011900950A AU2011900950A0 (en) 2011-03-17 A drill bit

Publications (1)

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WO2012051648A1 true WO2012051648A1 (fr) 2012-04-26

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3048241A1 (fr) * 2015-01-23 2016-07-27 Sandvik Intellectual Property AB Trépan rotatif à panne fendue
CN107191142A (zh) * 2017-06-19 2017-09-22 中铁上海工程局集团有限公司 一种四翼合金钻头的钻具及其使用方法
CN110469270A (zh) * 2018-05-11 2019-11-19 成都百施特金刚石钻头有限公司 一种具有防泥包功能的pdc钻头
CN113818812A (zh) * 2021-08-11 2021-12-21 沧州格锐特钻头有限公司 具有温度监测和降温功能的牙轮钻头

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113309472A (zh) * 2021-07-02 2021-08-27 重庆大学 一种三通道反循环钻头

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Publication number Priority date Publication date Assignee Title
US4381825A (en) * 1981-08-27 1983-05-03 Strata Bit Corporation Drill bit nozzle
EP0225082A2 (fr) * 1985-11-16 1987-06-10 Nl Petroleum Products Limited Trépan de forage rotatif
FR2606069A1 (fr) * 1986-11-04 1988-05-06 Vennin Henri Outil de forage monobloc rotatif
US6227316B1 (en) * 1999-03-10 2001-05-08 Dresser Industries, Inc. Jet bit with variable orifice nozzle
US20090057030A1 (en) * 2007-09-05 2009-03-05 Sandvik Mining And Construction Mining claw bit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4381825A (en) * 1981-08-27 1983-05-03 Strata Bit Corporation Drill bit nozzle
EP0225082A2 (fr) * 1985-11-16 1987-06-10 Nl Petroleum Products Limited Trépan de forage rotatif
FR2606069A1 (fr) * 1986-11-04 1988-05-06 Vennin Henri Outil de forage monobloc rotatif
US6227316B1 (en) * 1999-03-10 2001-05-08 Dresser Industries, Inc. Jet bit with variable orifice nozzle
US20090057030A1 (en) * 2007-09-05 2009-03-05 Sandvik Mining And Construction Mining claw bit

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3048241A1 (fr) * 2015-01-23 2016-07-27 Sandvik Intellectual Property AB Trépan rotatif à panne fendue
WO2016116390A1 (fr) * 2015-01-23 2016-07-28 Sandvik Intellectual Property Ab Trépan à griffe rotative
CN107109904A (zh) * 2015-01-23 2017-08-29 山特维克知识产权股份有限公司 一种旋转爪钻头
CN107109904B (zh) * 2015-01-23 2020-08-18 山特维克知识产权股份有限公司 一种旋转爪钻头
US10781641B2 (en) 2015-01-23 2020-09-22 Sandvik Intellectual Property Ab Rotary claw drill bit
CN107191142A (zh) * 2017-06-19 2017-09-22 中铁上海工程局集团有限公司 一种四翼合金钻头的钻具及其使用方法
CN110469270A (zh) * 2018-05-11 2019-11-19 成都百施特金刚石钻头有限公司 一种具有防泥包功能的pdc钻头
CN113818812A (zh) * 2021-08-11 2021-12-21 沧州格锐特钻头有限公司 具有温度监测和降温功能的牙轮钻头
CN113818812B (zh) * 2021-08-11 2024-01-26 沧州格锐特钻头有限公司 具有温度监测和降温功能的牙轮钻头

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