Gage Design-Effects of Gage Pad Length, Geometry and Activity (Side Cutting)on PDC Bit Stability, Steerability, and Borehole Quality in Rotary SteerableDrilling Applications

摘要

Technical and operational success, in rotary steerabledrilling (RSD) programs, requires optimization of thefollowing performance qualifiers (PQ)1 – stability, rateof penetration (ROP), steerability, durability andborehole quality. Bottom hole assembly (BHA) designand drill bit development must aid in the optimizationprocess.Rotary Steerable Systems 2,3 (RSS), based on their designand operational principles, exhibit different functionalcharacteristics. This realization necessitates the need forspecialized PDC bits 4,5 , for the different RSS tools.Technologies and/or features incorporated in these bitsmust enable optimization of the identified PQs.Three of the listed PQs - stability, steerability andborehole quality 6 - are directly influenced by a bit's gagedesign and configuration. This observation has createdan intense industry debate on the contributions of gagedesign, as they relate to the functionality, dynamicbehavior and overall performance of different RSS tools.This paper will isolate and evaluate the effects of gagedesign concepts in RSD applications. The discussionswill relate gage designs to PQ optimization, based onspecific RSD programs.Gage design theories, and functional characteristics, willbe supported by extensive field data.