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IPC Main Group
E21B 41/00

Equipment or details not covered by groups

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

5 direct subcodes

Child Classifications

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  • E21B 41/02 inhibition of corrosion in boreholes or wells
  • E21B 41/04 Manipulators for underwater operations, e.g. temporarily connected to well heads
  • E21B 41/06 Work chambers for underwater operations, e.g. temporarily connected to well heads
  • E21B 41/08 Underwater guide bases, e.g. drilling templates; Levelling thereof
  • E21B 41/1 Guide posts, e.g. releasable; Attaching guide lines to underwater guide bases

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