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WO2001086109A1 - Drill bit mounting for a downhole drilling machine - Google Patents

Drill bit mounting for a downhole drilling machine Download PDF

Info

Publication number
WO2001086109A1
WO2001086109A1 PCT/SE2001/000953 SE0100953W WO0186109A1 WO 2001086109 A1 WO2001086109 A1 WO 2001086109A1 SE 0100953 W SE0100953 W SE 0100953W WO 0186109 A1 WO0186109 A1 WO 0186109A1
Authority
WO
WIPO (PCT)
Prior art keywords
drill bit
drilling
machine
sleeve
shank
Prior art date
Application number
PCT/SE2001/000953
Other languages
French (fr)
Inventor
Fredrik EGERSTRÖM
Original Assignee
G-Drill Ab
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
Application filed by G-Drill Ab filed Critical G-Drill Ab
Priority to AU56897/01A priority Critical patent/AU5689701A/en
Publication of WO2001086109A1 publication Critical patent/WO2001086109A1/en

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
    • E21B7/00—Special methods or apparatus for drilling
    • E21B7/04—Directional drilling
    • E21B7/06—Deflecting the direction of boreholes
    • E21B7/064—Deflecting the direction of boreholes specially adapted drill bits therefor
    • 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
    • E21B47/00—Survey of boreholes or wells
    • E21B47/01—Devices for supporting measuring instruments on drill bits, pipes, rods or wirelines; Protecting measuring instruments in boreholes against heat, shock, pressure or the like
    • E21B47/013—Devices specially adapted for supporting measuring instruments on drill bits
    • 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
    • E21B10/36—Percussion drill bits
    • 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
    • E21B4/00—Drives for drilling, used in the borehole
    • E21B4/06—Down-hole impacting means, e.g. hammers
    • E21B4/14—Fluid operated hammers

Definitions

  • This invention relates to a drill bit mounting arrangement in a downhole drilling machine that has a drill bit with a shank, in which the shank is in a splined connection with a sleeve which is fixed in the housing of the machine, and a retainer element is arranged to limit the forward axial movability of the shank in the splined connection.
  • Downhole drilling machines of this kind are used primarily for drilling in hard rock. They are often used for drilling water wells, but they are also used for drilling blast holes and for other purposes. They have a built-in impact motor with a hammer that impacts directly on the shank of the drill bit. They are mounted on a drill tube that is rotated and thereby rotates the drilling machine. The drill tube also feeds the machine forwards and provides it with drive fluid that can be compressed air or high-pressure water.
  • the drill bit in the mounting arrangement as defined above is unsymmetrical and the splined connection is such that the drill bit fits in the sleeve only in a defined angular position, the sleeve has such a connection with the machine housing that the sleeve fits in the machine housing only in a defined angular position, and a locking sleeve with a threaded connection to the machine housing is arranged to axially clamp the sleeve against an axial abutment in the machine housing.
  • Figure 1 is a side view of the front portion of a drill string with a downhole drilling machine.
  • Figure 2 is a section through mounting elements for the drill bit of the drilling machine.
  • Figure 3 is a section taken along lines 3-3 in figure 1.
  • Figure 4 is a view seen as indicated by the arrows 4 in figure 2.
  • a drill string 10 comprises a plurality of string elements screwed together, and the foremost string 11 , the adapter, carries a drilling machine 12 screwed to it.
  • the string elements are in the form of extension tubes that lead pressure fluid (compressed air or high-pressure water) to the downhole drilling machine, which is an impacting drilling machine with a piston hammer 13.
  • the pressure fluid reciprocates the piston hammer to impact on the drill bit 14 of the drilling machine with a frequency of for example 65 Hz.
  • the drilling machine with its impact motor will not be described but reference is made to EP-0733 153-B that shows an example of such a machine that is driven by high-pressure water. In figure 2, only the front part of the piston hammer 13 of the drilling machine is shown.
  • the drill bit 14 has a head 15 and a shank 16, and the hammer piston 13 impacts on the end face of the shank 16.
  • the shank 16 has an annular recess 17.
  • the front portion of the shank has a splined connection 18 with a sleeve 19 that has an outward splined connection with the housing 21 of the drilling machine.
  • At the rear of the recess 17 of the shank there is a circular guiding surface 22 against a guiding sleeve 23 that takes support on a shoulder 24 in the housing 21 of the drilling machine.
  • a locking sleeve 25 with a threaded connection 26 with the housing 21 clamps axially the sleeve 19, a ring 27, and the guiding sleeve 23 against the shoulder 24.
  • the ring 27 is divided in two half-circular parts so that it can be mounted to be in the recess 17 of the shank.
  • the drill bit is limitedly movable between a rear position in which it is shown with its head 15 in abutment with the locking sleeve 25 and a front position defined by the ring 27 in the recess 17.
  • the threaded connection 26 of the locking sleeve will not be subjected to torque during drilling but all the torque is taken up by the splined connections 18,20.
  • the splined connection 20 is unsymmetrical in that one set of key and groove is missing at 30 so that the sleeve 19 can be mounted only in a single angular position in the housing 21.
  • the splined connection 18 of the drill bit shank is also unsymmetrical in that it has a key 31 that is wider than the other keys so that the drill bit 14 can be mounted only in a single angular position in the sleeve 19.
  • the major part of the drilling face of the drill bit head 15 is circular and centric with respect to the axis I of rotation, but the head has a sector 33 with larger radius so that the drill bit becomes unsymmetrical.
  • the drilling face has a plurality of so called hard metal buttons 34 and flushing fluid channels 35 end in the drilling face which has grooves 36 for leading away flushing fluid and debris. The machine drills straight holes when the drill string 11 is rotated during drilling.
  • the adapter 11 has a defined angular position with respect to the housing 21 and since the drill bit 14 can only be mounted in a single angular position with respect to the housing of the drilling machine, the angular position of the drill bit with respect to the adapter is always defined.
  • the adapter 11 contains sensors that give information of the direction of the drill bit in three dimensions and also information of the position of turning of the drill bit.
  • the drilling is interrupted and the signals transmitted up through the drill string is read and with the information therefrom, one can turn the drill string to get the drill bit into desired angle of turning for directional drilling. With oscillating turning about this position of the drill bit instead of rotation, the drill bit will drill a curved path.
  • the oscillation can for example be 45° about the desired direction of deviation.
  • This directional drilling is then interrupted and the direction is checked.
  • drilling with rotation of the drill string is resumed and the drilling is then straight.
  • the drilling is again interrupted and the direction of drilling is checked and again corrected if necessary.
  • this drilling equipment it is possible to drill both through soft formations and hard rock.
  • a tube for example a polyethylene tube to the drill string so that the tube will replace the drill string when the drill string is pulled out.

Landscapes

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

Abstract

A downhole drilling machine (12) can be used for directional drilling for example for drilling through roadbeds. The drill bit (14) of the machine has an unsymmetrical face so that it drills a curved hole when it drills without being rotated. When it is rotated, it drills straight. The shank (16) of the drill bit has an unsymmetrical splined connection (18) with a sleeve (19) which in its turn has an unsymmetrical splined connection with the housing (21) of the machine. The machine adapter (11) has sensors that provide information of the direction and angular position of the adapter.

Description

Drill bit mounting for a downhole drilling machine
Technical field of the invention
This invention relates to a drill bit mounting arrangement in a downhole drilling machine that has a drill bit with a shank, in which the shank is in a splined connection with a sleeve which is fixed in the housing of the machine, and a retainer element is arranged to limit the forward axial movability of the shank in the splined connection.
Technical background
Downhole drilling machines of this kind are used primarily for drilling in hard rock. They are often used for drilling water wells, but they are also used for drilling blast holes and for other purposes. They have a built-in impact motor with a hammer that impacts directly on the shank of the drill bit. They are mounted on a drill tube that is rotated and thereby rotates the drilling machine. The drill tube also feeds the machine forwards and provides it with drive fluid that can be compressed air or high-pressure water.
It is today common practice to drill through roadbeds, under rivers and the like in order to provide holes for conduits and lines of various kinds. When drilling such holes, it is often necessary to have the possibility to control the direction and to drill bent holes. Difficulties arises if the drill bit encounters hard rock or boulders because drilling arrangements of this kind is normally not adapted for drilling in hard rock.
Object of invention and brief description of the invention
It is an object of the invention to make possible directional drilling with a downhole drilling machine.
To this end, the drill bit in the mounting arrangement as defined above is unsymmetrical and the splined connection is such that the drill bit fits in the sleeve only in a defined angular position, the sleeve has such a connection with the machine housing that the sleeve fits in the machine housing only in a defined angular position, and a locking sleeve with a threaded connection to the machine housing is arranged to axially clamp the sleeve against an axial abutment in the machine housing. The invention is defined by the characteristics defined in the claims
Brief description of the drawings
The figures shows a preferred embodiment of the invention.
• Figure 1 is a side view of the front portion of a drill string with a downhole drilling machine.
• Figure 2 is a section through mounting elements for the drill bit of the drilling machine.
• Figure 3 is a section taken along lines 3-3 in figure 1.
• Figure 4 is a view seen as indicated by the arrows 4 in figure 2.
Description of a preferred embodiment of the invention
A drill string 10 comprises a plurality of string elements screwed together, and the foremost string 11 , the adapter, carries a drilling machine 12 screwed to it. The string elements are in the form of extension tubes that lead pressure fluid (compressed air or high-pressure water) to the downhole drilling machine, which is an impacting drilling machine with a piston hammer 13. The pressure fluid reciprocates the piston hammer to impact on the drill bit 14 of the drilling machine with a frequency of for example 65 Hz. The drilling machine with its impact motor will not be described but reference is made to EP-0733 153-B that shows an example of such a machine that is driven by high-pressure water. In figure 2, only the front part of the piston hammer 13 of the drilling machine is shown.
The drill bit 14 has a head 15 and a shank 16, and the hammer piston 13 impacts on the end face of the shank 16. The shank 16 has an annular recess 17. The front portion of the shank has a splined connection 18 with a sleeve 19 that has an outward splined connection with the housing 21 of the drilling machine. At the rear of the recess 17 of the shank, there is a circular guiding surface 22 against a guiding sleeve 23 that takes support on a shoulder 24 in the housing 21 of the drilling machine. A locking sleeve 25 with a threaded connection 26 with the housing 21 clamps axially the sleeve 19, a ring 27, and the guiding sleeve 23 against the shoulder 24. The ring 27 is divided in two half-circular parts so that it can be mounted to be in the recess 17 of the shank. Axially, the drill bit is limitedly movable between a rear position in which it is shown with its head 15 in abutment with the locking sleeve 25 and a front position defined by the ring 27 in the recess 17. The threaded connection 26 of the locking sleeve will not be subjected to torque during drilling but all the torque is taken up by the splined connections 18,20.
As can be seen from figure 3, the splined connection 20 is unsymmetrical in that one set of key and groove is missing at 30 so that the sleeve 19 can be mounted only in a single angular position in the housing 21. The splined connection 18 of the drill bit shank is also unsymmetrical in that it has a key 31 that is wider than the other keys so that the drill bit 14 can be mounted only in a single angular position in the sleeve 19.
The major part of the drilling face of the drill bit head 15 is circular and centric with respect to the axis I of rotation, but the head has a sector 33 with larger radius so that the drill bit becomes unsymmetrical. As is conventional in the art, the drilling face has a plurality of so called hard metal buttons 34 and flushing fluid channels 35 end in the drilling face which has grooves 36 for leading away flushing fluid and debris. The machine drills straight holes when the drill string 11 is rotated during drilling.
The adapter 11 has a defined angular position with respect to the housing 21 and since the drill bit 14 can only be mounted in a single angular position with respect to the housing of the drilling machine, the angular position of the drill bit with respect to the adapter is always defined. The adapter 11 contains sensors that give information of the direction of the drill bit in three dimensions and also information of the position of turning of the drill bit. The drilling is interrupted and the signals transmitted up through the drill string is read and with the information therefrom, one can turn the drill string to get the drill bit into desired angle of turning for directional drilling. With oscillating turning about this position of the drill bit instead of rotation, the drill bit will drill a curved path. The oscillation can for example be 45° about the desired direction of deviation. This directional drilling is then interrupted and the direction is checked. When the direction of drilling is the desired direction, drilling with rotation of the drill string is resumed and the drilling is then straight. After a certain distance of drilling, the drilling is again interrupted and the direction of drilling is checked and again corrected if necessary. With this drilling equipment, it is possible to drill both through soft formations and hard rock. When drilling for example through a roadbed is finished, one couples a tube, for example a polyethylene tube to the drill string so that the tube will replace the drill string when the drill string is pulled out.

Claims

Claims
A drill bit mounting arrangement in a downhole drilling machine (14) that has a drill bit (14) with a shank (16), in which the shank is in a splined connection (18) with a sleeve (19) which is fixed in the housing (21) of the machine, and a retainer element (27) is arranged to limit the forward axial movability of the shank in the splined connection (18), characterised in that
• the drill bit (14) is unsymmetrical and the splined connection (18) is such that the drill bit fits in the sleeve (19) only in a defined angular position,
• the sleeve (19) has such a connection (20) with the machine housing (21) that the sleeve (19) fits in the machine housing only in a defined angular position, and
• a locking sleeve (25) with a threaded connection (26) to the machine housing is arranged to axially clamp the sleeve (19) against an axial abutment (24) in the machine housing.
PCT/SE2001/000953 2000-05-05 2001-05-03 Drill bit mounting for a downhole drilling machine WO2001086109A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU56897/01A AU5689701A (en) 2000-05-05 2001-05-03 Drill bit mounting for a downhole drilling machine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0001657A SE515730C2 (en) 2000-05-05 2000-05-05 The drill bit attachment
SE0001657-6 2000-05-05

Publications (1)

Publication Number Publication Date
WO2001086109A1 true WO2001086109A1 (en) 2001-11-15

Family

ID=20279556

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2001/000953 WO2001086109A1 (en) 2000-05-05 2001-05-03 Drill bit mounting for a downhole drilling machine

Country Status (3)

Country Link
AU (1) AU5689701A (en)
SE (1) SE515730C2 (en)
WO (1) WO2001086109A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3924690A (en) * 1973-01-09 1975-12-09 Halifax Tool Co Ltd Percussion drill control means
US4508182A (en) * 1983-07-20 1985-04-02 Dailey Petroleum Services Corp. Method and apparatus for controlling azimuthal drift of a drill bit
US5368110A (en) * 1993-10-28 1994-11-29 Texaco Inc. Downhole rotary bearing sub
WO1995016847A1 (en) * 1993-12-13 1995-06-22 G-Drill Ab A hydraulic impact motor
WO2000055467A1 (en) * 1999-03-03 2000-09-21 Earth Tool Company, L.L.C. Method and apparatus for directional boring

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3924690A (en) * 1973-01-09 1975-12-09 Halifax Tool Co Ltd Percussion drill control means
US4508182A (en) * 1983-07-20 1985-04-02 Dailey Petroleum Services Corp. Method and apparatus for controlling azimuthal drift of a drill bit
US5368110A (en) * 1993-10-28 1994-11-29 Texaco Inc. Downhole rotary bearing sub
WO1995016847A1 (en) * 1993-12-13 1995-06-22 G-Drill Ab A hydraulic impact motor
WO2000055467A1 (en) * 1999-03-03 2000-09-21 Earth Tool Company, L.L.C. Method and apparatus for directional boring

Also Published As

Publication number Publication date
SE0001657L (en) 2001-10-01
AU5689701A (en) 2001-11-20
SE515730C2 (en) 2001-10-01
SE0001657D0 (en) 2000-05-05

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