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CPC Main Group
E21B 43/00

Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells (applicable only to water E03B)

16 direct subcodes

Child Classifications

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  • E21B 43/14 Obtaining from a multiple-zone well
  • E21B 43/285 Melting minerals, e.g. sulfur (E21B43/24 takes precedence)
  • E21B 43/295 Gasification of minerals, e.g. for producing mixtures of combustible gases (E21B43/243 takes precedence)
  • E21B 43/32 Preventing gas- or water-coning phenomena, i.e. the formation of a conical column of gas or water around wells

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