IPC Main Group
E21B 31/00 Fishing for or freeing objects in boreholes or wells
Introduced: September 1968
Last revised: January 2006
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
Related Keywords
freeing objects in BOREHOLESextractors for broken drillsFISHING -tools for boreholesSCOOP(S) as fishing tools in boreholes
5 direct subcodes
Child Classifications
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- E21B 31/03 Freeing by flushing
- E21B 31/06 using magnetic means
- E21B 31/08 using junk baskets or the like
- E21B 31/107 using impact means for releasing stuck parts, e.g. jars
- E21B 31/12 Grappling tools, e.g. tongs or grabs
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