Borehullsforgrening og fremgangsmåte for å opprette en borehullsforgrening

摘要

New wellbore milling systems and methods of their use have been developed, the milling system in one aspect including at least one mill, at least one stabilizing member connected to and above the at least one mill, and the at least one stabilizing member for maintaining position of the at least one mill for milling through the liner into the main wellbore. In certain aspects multiple spaced-apart stabilizers are used above a mill which, in one aspect, may include one or more reaming stabilizers. In one aspect the lowermost stabilizer is spaced-apart from a mill so that the stabilizer does not enter a bend portion of a liner to be milled until milling has commenced.