Study of Mud Removal from the Drill Bit Zone into the Space Outside the Drill Pipe.

A study was made of the patterns of mud removal from the cutting zone, using a three-cutter drill bit with a composite system of hydraulic channels making it possible to employ a number of different flushing schemes. Using a special test bed facility, the main patterns of change in the characteristics of the mud-removal process were determined for ten different flushing schemes. It is shown that the process of mud removal can be optimized by using drill bits with an asymmetrical arrangement of the nozzles, by bringing the bits closer to the cutting face, and by using bits with openings in the teeth.