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 21/01 Arrangements for handling drilling fluids or cuttings outside the borehole, e.g. mud boxes
- E21B 21/02 Swivel joints in hose lines
- E21B 21/06 Arrangements for treating drilling fluids outside the borehole
- 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
- HALLIBURTON ENERGY SERVICES GROUP US 26,607
- PETROCHINA COMPANY 14,382
- SINOPEC (CHINA PETROCHEMICAL CORPORATION) 10,137
- CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 6,517
- BAKER HUGHES US 6,269
- SCHLUMBERGER TECHNOLOGY US 5,929
- SAUDI ARABIAN OIL COMPANY SA 5,880
- SOUTHWEST PETROLEUM UNIVERSITY 4,477
- CHINA UNIVERSITY OF MINING AND TECHNOLOGY 4,357
- SCHLUMBERGER TECHNOLOGY NL 4,219