trépan annulaire

CONT: L'outil de forage est généralement un trépan annulaire, travaillant en percussion. Il existe des machines mixtes qui forent en percussion, associée à une rotation.

CONT: By using special annular bits, core samples may be extracted from a bore so that a continuous geological record can be made available of all the penetrated strata.
OBS: annular: Pertaining to the annulus. The annulus is sometimes referred to as the annular space.
OBS: Annular space: The space between two concentric circles. In the petroleum industry, it is usually the space surrounding a pipe in the wellbore, or the space between tubing and casing, or the space between tubing and the wellbore ...