دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a bit that does not drill out the centre portion of the hole, but allows this centre portion (the core) to pass through the round opening in the centre of the bit and into the core barrel.

n: The drill bit that breaks the annular rock at bottom and matchs with coring tool.

v: 1. to remove with the bit the residual cement that normally remains in the lower section of casing and the wellbore after the casing has been cemented.2. to remove the settlings and cavings that are plugged inside a hollow fish (such as drill pipe) during a fishing operation.

drilling through the cement after a primary cement job as the hole is deepened.

n: drilling more 3m small hole when drill out the whipstock

v: the string of tools used to drill off the casing accessories and cement and also drill out the casing

n: a method of casingless completion in which low the oil string to the top of oil or gas layer after drill out the pay formation

n: a special bit or mill run on a cable-tool drilling line, a well servicing rig, or the sandline of a rotary drilling rig to mill out tools or drill out downhole debris.

n: A kind of fishing tool with bit,which can drill out the barrier in the bottomhole.