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IPC Subgroup
E21B 43/22

Use of chemicals or bacterial activity

Introduced: September 1968

Last revised: January 2006

Full Title

Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells > Enhanced recovery methods for obtaining hydrocarbons > Use of chemicals or bacterial activity

Classification Context

Section:
FIXED CONSTRUCTIONS
Class:
EARTH OR ROCK DRILLING; MINING
Subclass:
EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

Additional Content

Methods for stimulating production in obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells by forming crevices or fractures by use of eroding chemicals, e.g. acids

Top Applicants

Top 10 applicants by patent filingsfor 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