CPC Main Group
E21B 25/00 Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors (core bits E21B10/02)
7 direct subcodes
Child Classifications
Navigate with arrow keys, Enter to open
- E21B 25/02 the core receiver being insertable into, or removable from, the borehole without withdrawing the drilling pipe
- E21B 25/06 the core receiver having a flexible liner or inflatable retaining means
- E21B 25/08 Coating, freezing, consolidating cores (E21B25/06 takes precedence); Recovering uncontaminated cores or cores at formation pressure
- E21B 25/10 Formed core retaining or severing means (E21B25/06, E21B25/08 take precedence)
- E21B 25/16 for obtaining oriented cores
- E21B 25/18 the core receiver being specially adapted for operation under water