IPC Subgroup
E21B 43/16 Enhanced recovery methods for obtaining hydrocarbons
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
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
5 direct subcodes
Child Classifications
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- E21B 43/17 Interconnecting two or more wells by fracturing or otherwise attacking the formation
- E21B 43/18 Repressuring or vacuum methods
- E21B 43/2 Displacing by water
- E21B 43/22 Use of chemicals or bacterial activity
- E21B 43/24 using heat, e.g. steam injection
Top Applicants
Top 10 applicants by patent filingsfor 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