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DIFF Subgroup
E21B 3/02

Surface drives for rotary drilling

Introduced: September 1968

Full Title

Rotary drilling > Surface drives for rotary drilling

Of 5 combined children, 4 exist in both systems.

1 codes are CPC-only extensions.

Child Classifications

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  • E21B 3/022 CPC only CPC only
  • E21B 3/025 with a to-and-fro rotation of the tool since 2000 IPC+CPC Available in IPC and CPC
  • E21B 3/03 with an intermittent unidirectional rotation of the tool since 2000 IPC+CPC Available in IPC and CPC
  • E21B 3/035 with slipping or elastic transmission since 2000 IPC+CPC Available in IPC and CPC

Top Applicants

Top Applicants (IPC)

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

Top Applicants (CPC)

Class E21,2013–2023, worldwide · Source: EPO PATSTAT

  1. HALLIBURTON ENERGY SERVICES GROUP US 27,652
  2. SAUDI ARABIAN OIL COMPANY SA 7,755
  3. PETROCHINA COMPANY 7,025
  4. BAKER HUGHES US 6,589
  5. SCHLUMBERGER TECHNOLOGY US 6,151
  6. SINOPEC (CHINA PETROCHEMICAL CORPORATION) 4,443
  7. SCHLUMBERGER TECHNOLOGY NL 4,255
  8. CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 3,991
  9. SERVICES PETROLIERS SCHLUMBERGER FR 3,300
  10. SCHLUMBERGER CANADA CA 3,086