Apparatus and methods are provided which enhance drilling and completion of wellbore intersections. In a described embodiment, a cutting tool diverter is used to drill a branch wellbore extending outwardly from a main wellbore. The diverter is provided with an outer easily millable portion which reduces the amount of time needed to retrieve the diverter. In another embodiment, a substance is injected into a formation surrounding the intersection of the main and branch wellbores, to thereby facilitate sealing of the intersection.