Roller cone bi-center bit

摘要: A roller cone bi-center bit for economically drilling an enlarged borehole below casing in earth formation is provided. The includes a rolling cutter or other appropriate to enlarge pilot bore also made by type of cutters. comprises single-diameter body with recess accommodate the trailing which enlarges bore. may provide ability change out cutters efficiently field. are oriented enhance cement plug at bottom casing. be mounted on segments designed easily removed replacement adjustment position