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IPC Main Group
E21B 21/00

Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor

Introduced: September 1968

Last revised: January 2006

Classification Context

Section:
FIXED CONSTRUCTIONS
Class:
EARTH OR ROCK DRILLING; MINING
Subclass:
EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

Additional Content

Freeing objects stuck in boreholes by flushing

Related Keywords

flushing BOREHOLEScompositions for laying DUST in connection with the operation of percussive toolseliminating DUST during drilling in minesFLUSHING of boreholes

9 direct subcodes

Child Classifications

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  • E21B 21/02 Swivel joints in hose lines
  • E21B 21/08 Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure
  • E21B 21/1 Valves arrangements in drilling-fluid circulation systems
  • E21B 21/12 using drilling pipes with plural fluid passages, e.g. closed circulation systems
  • E21B 21/14 using liquids and gases, e.g. foams
  • E21B 21/16 using gaseous fluids
  • E21B 21/18 Preventing exhaust air from the drill motor from blowing-off towards the working face

Top Applicants

Top 10 applicants by patent filingsfor class E21, 2013–2023, worldwide · Source: EPO PATSTAT

  1. HALLIBURTON ENERGY SERVICES GROUP US 26,607
  2. PETROCHINA COMPANY 14,382
  3. SINOPEC (CHINA PETROCHEMICAL CORPORATION) 10,137
  4. CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 6,517
  5. BAKER HUGHES US 6,269
  6. SCHLUMBERGER TECHNOLOGY US 5,929
  7. SAUDI ARABIAN OIL COMPANY SA 5,880
  8. SOUTHWEST PETROLEUM UNIVERSITY 4,477
  9. CHINA UNIVERSITY OF MINING AND TECHNOLOGY 4,357
  10. SCHLUMBERGER TECHNOLOGY NL 4,219