Abstract: A method is provided that allows the operator to re-enter a primary wellbore from a lateral wellbore after the lateral wellbore has been completed. The method generally comprises the steps of locating a cutting device such as a milling bit adjacent a tubular such as a liner within a wellbore, rotating the milling bit while maintaining an axial position of the milling bit relative to the liner to initiate an opening, and rotating and axially advancing the milling bit to complete the opening. In addition, a bottom hole assembly that facilitates re-entry into the primary wellbore from a lateral wellbore is provided. The bottom hole assembly generally includes a drill collar or other heavy pipe structure, and a mill. The mill has a body and cutting structures. The cutting structures apply lateral force against a surrounding pipe to form an initial lip through the wall of the pipe.

Abstract: This miling tool for underground work consists of a tool body which has a plurality of cutter blades. Each cutter blade has a negative axial rake and an essentially constant negative radial rake. In addition, each cutter arm has a close packing of cylindrical cutting grade tungsten carbide inserts set at a lead angle of about 0 to 10 degrees. The inserts are also preferably vertically offset on adjacent cutting blades.