Telescoping joints for varying drill string lengths; Shock absorbers

Introduced: January 1980

Full Title

Full titles differ between systems:

IPC:

Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Casings; Tubings > Couplings; Joints > between rod and bit, or between rod and rod > Telescoping joints for varying drill string lengths; Shock absorbers

CPC:

Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Casings; Tubings > Couplings; joints > between rod and bit or between rod and rod > Telescoping joints for varying drill string lengths; Shock absorbers

Of 2 combined children, 0 exist in both systems.

2 codes are CPC-only extensions.

Child Classifications

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E21B 17/073 CPC only CPC only
E21B 17/076 CPC only CPC only

Top Applicants

Top Applicants (IPC)

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

Top Applicants (CPC)

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