Rotor underreamer, section mill, casing cutter, casing scraper and drill string centralizer

摘要

A down hole well bore apparatus to underream and remove rock or cement or other material, cut or mill casing, clean or scrape casing, or centralize a drill string, which has a rotor which actuates blades, a compact overall length and can be operated with normal or reverse circulation. Simultaneous operations or multiple sequential operations can be made without removing the drill string.