دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a bottomhole assembly consisting of stabilisers and largediameter drill collars arranged in a particular configuration to maintain drift angle and direction of a hole. This assembly is often necessary in crooked hole country. See crooked hole country.

n: a special drill collar, square but with rounded edges, used to control the straightness or direction of the bole;often part of a packed-bole assembly.

n: The drill collar that outside are square and inner are round.