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CPC Main Group
E21D 3/00

Raising shafts, i.e. working upwards from the bottom

Filing statistics

CPC E21D 3/00 belongs to the parent subclass E21D, which recorded 43,973 patent applications worldwide between 2013 and 2023. Annual filings grew from 1,000 in 2013 to 6,074 in 2023 (+507%), peaking at 6,255 applications in 2020. The most active applicants in class E21 are HALLIBURTON ENERGY SERVICES GROUP (27,652 applications), SAUDI ARABIAN OIL COMPANY (7,755 applications) and PETROCHINA COMPANY (7,025 applications).

Source: EPO PATSTAT, worldwide filings

Top Applicants

Top 10 applicants by patent filingsfor 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