Apparatus and method for milling through a whipstock in a wellbore

摘要

A method for milling within a whipstock set in a wellbore comprises introducing a mill guide (30) having a channel therethrough into the wellbore above the whipstock. The mill guide is moved into stabilising contact with the whipstock and a mill is guided by the mill guide to mill down into the whipstock. The mill has at least a portion thereof in contact with the mill guide while milling into the whipstock.