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IPC Subgroup
E21B 17/02

Couplings; Joints

Introduced: September 1968

Last revised: January 2006

Full Title

Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Casings; Tubings > Couplings; Joints

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

3 direct subcodes

Child Classifications

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  • E21B 17/03 between drilling rod or pipe and drill motor, e.g. between drilling rod and hammer
  • E21B 17/08 Casing joints

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