Development and successful application of unique steerable PDC bits

Abstract

This paper describes the development and successful application of unique polycrystalline diamond compact (PDC) bits for use on steerable motor assemblies. The development phase comprised an extensive series of laboratory and field experiments. These showed that proper design of face and gauge aggressiveness were the keys to improved steerability. Notably, the common perception that a short, aggressive gauge is required for steerability was found to be misguided. Field applications from around the world have demonstrated that the new designs minimize tool face fluctuations despite erratic weight on bit (WOB), allow the theoretical build up rate (BUR) to be attained, create superior quality well bores, and provide improved net rates of penetration (ROP) over conventional designs.