ROLLER-CUTTER DRILLING BIT Russian patent published in 2002 - IPC

FIELD: well drilling with use of jet drilling bits. SUBSTANCE: roller-cutter drilling bit has legs with axles, roller cutters installed on them by means of bearings with teeth rows reinforced with hard-alloy teeth or milled teeth, three an more jet nozzles located on bit body for jet formation. All roller cutters, except for one of them, are truncated and having only periphery teeth rows To provide for direct action of jets onto bottom hole, nozzles are arranged over entire bottom hole radius in bit body so that jet axis formed by the first jet nzzle is oriented so that point of intersection of jet axis with bottom hole surface coincides with middle circumference of breakage annular channel from top teeth row of roller cutter, and jet axis formed by the second jet nozzle coincides with middle circumference of breakage annular channel from periphery teeth rows of all roller cutters. Axes of jets of other nozzles are uniformly distributed between the first and second nozzles. EFFECT: increased drilling bit operating reliability and efficiency due to increased drilling rate owing to efficient use of hydraulic jets energy. 2 dwg