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IPC Main Group
E21B 47/00

Survey of boreholes or wells

Introduced: September 1968

Last revised: January 2012

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

Glossary

borehole boreholes an unlined shaft drilled into the ground, typically for the purposes of extracting water, crude oil or natural gas this is often referred to as the wellbore.

Limiting references

Monitoring pressure or flow of drilling fluid

Related Keywords

surveying BOREHOLESSURVEYING of boreholes

15 direct subcodes

Child Classifications

Navigate with arrow keys, Enter to open

  • E21B 47/001 for underwater installations
  • E21B 47/002 by visual inspection
  • E21B 47/003 Determining well or borehole volumes
  • E21B 47/005 Monitoring or checking of cementation quality or level
  • E21B 47/007 Measuring stresses in a pipe string or casing
  • E21B 47/26 Storing data down-hole, e.g. in a memory or on a record carrier

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