Recent advances in rotary drill bits

This review of new developments in rotary drilling bit design discusses economic gains and performance improvements, including new developments in cutting structure, bearings, materials, bit designs and drilling techniques. Increased drilling costs have created greater interest in the economics afforded by longer bit life and faster penetration rates. The following areas of significance are discussed: increased life of solid journal bearing bits, new improved soft formation bits, improved rolling cone core bits and re-entry bits.