CPC Main Group
E21B 4/00 Drives for drilling, used in the borehole
8 direct subcodes
Child Classifications
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- E21B 4/02 Fluid rotary type drives
- E21B 4/04 Electric drives (E21B4/12 takes precedence)
- E21B 4/06 Down-hole impacting means, e.g. hammers (boring rams E21B11/02)
- E21B 4/16 Plural down-hole drives, e.g. for combined percussion and rotary drilling (E21B4/10 takes precedence); Drives for multi-bit drilling units
- E21B 4/18 Anchoring or feeding in the borehole
- E21B 4/20 combined with surface drive (E21B4/10 takes precedence)
Top Applicants
Top 10 applicants by patent filingsfor class E21, 2013–2023, worldwide · Source: EPO PATSTAT
- HALLIBURTON ENERGY SERVICES GROUP US 27,652
- SAUDI ARABIAN OIL COMPANY SA 7,755
- PETROCHINA COMPANY 7,025
- BAKER HUGHES US 6,589
- SCHLUMBERGER TECHNOLOGY US 6,151
- SINOPEC (CHINA PETROCHEMICAL CORPORATION) 4,443
- SCHLUMBERGER TECHNOLOGY NL 4,255
- CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 3,991
- SERVICES PETROLIERS SCHLUMBERGER FR 3,300
- SCHLUMBERGER CANADA CA 3,086