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
  • E21B10/61—Drill bits characterised by conduits or nozzles for drilling fluids characterised by the nozzle structure
• • 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
  • E21B7/18—Drilling by liquid or gas jets, with or without entrained pellets
• • 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

Definitions

• This invention relates to the design of the nozzles and rotatable nozzle assembly for a fluid drilling head of the type generally described in our earlier international patent application PCT/AU02/01550 (international publication No. WO 03/042491 A1 ), the content of which is incorporated herein by way of cross reference.
• the present invention therefore provides a fluid cutting head of the type having a plurality of nozzles in a rotatable nozzle assembly for cutting a bore hole in rock, said nozzles being arranged to be supplied with high pressure drilling fluid, forming jets positioned to cut adjacent rock, said nozzles including one or more generally axially facing pilot nozzles and one or more generally radially facing reaming nozzles, at least the pilot nozzles being characterised by a non-tapering outlet section such that the jet issuing therefrom is of substantially constant cross-section in a zone immediately adjacent the outlet section.
• the reaming nozzles are also characterised by a non -tapering outlet section such that the jet issuing therefrom is of substantially constantly cross- section in a zone immediately adjacent the outlet section.
• the leading part of the rotatable nozzle assembly incorporating the pilot nozzles is of significantly lesser diameter than the following part of the rotatable nozzle assembly incorporating the reaming nozzles.
• the following part of the rotatable nozzle assembly is formed in a stepwise fashion of steps of progressively increasing diameters, there being one reaming nozzle located in each step such that the jet issuing from each reaming nozzle is located close to the adjacent bore hole surface.
• Figure 1 is side view of a fluid drilling head according to the invention
• Figure 2 is a diagrammatic representation of a prior art fluid drilling head showing the formation of cavitation clouds remote from the nozzle outlets;
• Figure 3 is a right hand perspective view of the rotatable nozzle assembly of a fluid drilling head according to the invention.
• Figure 4 is a left hand perspective view of the rotatable nozzle assembly of a fluid drilling head according to the invention.
• Figure 5 is an end view of the rotatable nozzle assembly shown in Figures 3 and 4;
• Figure 6 is a side view of the rotatable nozzle assembly shown in Figures 3 and 4, and
• Figure 7 is a cross-sectional view through a nozzle of the type used in the fluid drilling head according to the invention.
• a fluid drilling head 8 typically has a rotatable nozzle assembly 9 and may incorporate other features such as a gauging ring 10 mounted at the leading end of a drill head body 1 1 .
• the rotatable nozzle assembly 13 is provided with pilot nozzles 14 and reaming nozzles 15 which are typically of a "horn nozzle” design having a diverging outlet portion.
• Nozzles of this type generate powerful cavitation clouds shown diagrammatically at 16 which are effective in cutting and breaking up rock. It has been found through careful laboratory testing that while the cavitation clouds 16 generated by the nozzles 14 and 15 are indeed powerful, they are remote from the nozzle outlets as clearly shown in Figure 2 resulting in a "dead zone" 17 between the cavitation cloud 16 and the nozzle outlets.
• the present invention overcomes this deficit by providing nozzles of the type shown in Figure 7 where the nozzle 18 is typically inserted into a hole 19 formed in the rotatable nozzle assembly 20 and secured in place by a threaded engagement 21 .
• the nozzle is typically formed to sit in a counter bore 22 such that the top of the nozzle thread 23 sits flush with the base of the counter bore.
• the outlet section 25 is formed of non-tapering section as is clearly seen in Figure 7 such that the jet issuing therefrom is of substantially constant cross-section in the zone immediately adjacent the outlet section.
• the reaming nozzles 3, 4, 5, and 6 are typically located to provide reaming jers as shown in Figures 3 and 4 and are located at 29, 30, 31 and 32 respectively as can be clearly seen in Figure 6.
• the following part 27 of the rotatable nozzle assembly 9 is formed in a stepwise fashion of progressively increasing diameters, there being one reaming nozzle located in each step such that the jet issuing from each reaming nozzle is located close to the adjacent bore hole surface.
• This effect is optimised by reducing the diameter of the leading part 26 as much as physically possible so that the pilot jet rock cutting function is reduced compared with the progressive enlargement of the bore hole diameter from the reaming jets in the following stepped parts 27.
• Nozzle diameters vary depending on the material and nozzle location.
• the front pilot nozzles need be no greater than 0.7mm to 1 .0 mm in diameter. It is best to minimise these sizes to improve net tool forward thrust, and a small change makes a big difference as they point virtually straight ahead.
• the reamers work well in the range between 0.5mm and 1 .3mm, again depending on the coal conditions.
• the 310 m hole was drilled with 0.8 straight ahead, 0.9 forward angled, and 1 .1 in the three reamers in this head. This, however, produced a penetration rate of around 1 m/min.
• a rotatable nozzle assembly for a fluid drilling head can be provided which allows faster drilling rates than has previously been achieved with prior art drilling heads and further allows more accurate control of the bore hole size, and the effective location of the reaming nozzles.

Landscapes

• Engineering & Computer Science (AREA)
• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Mechanical Engineering (AREA)
• Earth Drilling (AREA)
• Excavating Of Shafts Or Tunnels (AREA)
• Processing Of Stones Or Stones Resemblance Materials (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

Family

ID=46720019

Family Applications (1)

Country Status (8)

Families Citing this family (9)

Citations (3)

Family Cites Families (11)

• 2012
  • 2012-02-23 AU AU2012220354A patent/AU2012220354B2/en not_active Ceased
  • 2012-02-23 RU RU2016111932A patent/RU2016111932A/ru unknown
  • 2012-02-23 US US13/985,685 patent/US20130319773A1/en not_active Abandoned
  • 2012-02-23 CA CA2827989A patent/CA2827989A1/en not_active Abandoned
  • 2012-02-23 RU RU2013140288/03A patent/RU2586832C2/ru not_active IP Right Cessation
  • 2012-02-23 DE DE112012000985.1T patent/DE112012000985T5/de not_active Withdrawn
  • 2012-02-23 CN CN201280010556.8A patent/CN103429838B/zh not_active Expired - Fee Related
  • 2012-02-23 WO PCT/AU2012/000168 patent/WO2012113024A1/en not_active Ceased
  • 2012-02-23 PL PL406176A patent/PL226832B1/pl unknown

Patent Citations (3)

Non-Patent Citations (1)

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