دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: in pipeline construction. the hole drilled as the first step of a directionally drilled river crossing. It establishes a pathway for the pipeline.

n: a small-diameter hole that is later opened up to the required diameter. Sometimes used in directional drilling to control wellbore deviation during kick-off.

a small (sometimes) diameter hole drilled through a pay zone to determine the pay top and bottom or various contacts, before the main well position is selected. May also use a pilot hole to better control influx rate.