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PCE
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DIFF Main Group
E21B 37/00

Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence)

Introduced: September 1968

Title

Titles differ between systems:

IPC: Methods or apparatus for cleaning boreholes or wells

CPC: Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence)

Full Title

Full titles differ between systems:

IPC:

Methods or apparatus for cleaning boreholes or wells

CPC:

Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence)

Additional Content IPC

Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor

IPC and CPC are identically structured here. All 4 subcodes exist in both systems.

1 shared codes have differing titles between IPC and CPC.

Child Classifications

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  • E21B 37/06 using chemical means for preventing or limiting the deposition of paraffins or like substances since 1980 IPC+CPC Available in IPC and CPC
  • E21B 37/08 cleaning in situ of down-hole filters, screens, or gravel packs (E21B37/06 takes precedence) since 1980 IPC+CPC Available in IPC and CPC
  • E21B 37/10 Well swabs since 1980 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