Integrated PoF and CBM Strategies for Improving Electronics Reliability Performance of Downhole MWD and LWD Tools

Abstract

Abstract Electronics that operate under downhole drilling conditions, such as printed circuit board assemblies (PCBAs) in measurement-while-drilling (MWD)/logging-while-drilling (LWD) tools, can experience a significant amount of extremely high temperatures and vibration stresses over their lifetimes, which may induce failures during deployment. This study demonstrates the methodologies on integrated physics of failure (PoF) for improving the reliability performance of MWD/LWD tools. PoF discussed in this study is for identifying and understanding failure modes, failure mechanisms, and failure sites of drilling electronics for their particular life-cycle loading conditions. This PoF study is a systematic methodology, integrated with data acquisition technologies, conditional-based maintenance (CBM) and failure analysis techniques to actualize the real-time life management on improving maintenance decisions, and providing guidance to incorporate reliability into the well-planning and operation processes, thus enabling monetary savings for the oil company and the MWD/LWD service provider. Through data acquisition technologies, the drilling environmental profile is captured by the sensor and recorded in the memories of the MWD/LWD tool. Based on the drilling environmental profiles, the drilling stress and loading conditions are retrieved and calculated for estimating the remaining life of the drilling electronics. With CBM strategy, electronic units assessed with high risk results are excluded from being deployed to the field to avoid potential failure in the field. PoF is followed up to investigate the failure mechanism of units returned from field. Real-case studies on MWD/LWD tools operated onshore the U.S. and in the Asia Pacific region are presented. The objective of this study is to enable real-time electronics reliability assessment on MWD/LWD tools under their actual application conditions. When combined with PoF models, CBM strategy is capable of making continuously updated predictions on the remaining life of electronics based on the in-situ drilling environmental and operational conditions.