Optimization of Rock-Bit Life Based on Bearing Failure Criteria

Summary Recent advances in rock bit seal technology have allowed greater predictability of bearing life. Cone loss following bearing failure incurs predictability of bearing life. Cone loss following bearing failure incurs costs related to remedial activities. A risk analysis approach, utilising hearing life relationships and the inter-dependence of drilling events, is used to formulate a bit run cost optimisation method. The procedure enables a choice to be made between elastomeric and metal seals on a lowest replacement cost basis. The technique also provides a formal method for assessing the opportunity cost for employing a device for the downhole detection of bit bearing failures.