System Reliability and Metrics for High-Speed Networked Drillstring Telemetry and Along String Evaluation
Raymond McCubrey, Aaron Johnson, Rhys Adsit, Daan M. Veeningen, David S. Pixton · All Days · 2013
Abstract High-bandwidth downhole data transmission via a wired or networked drill string system provides an alternative to conventional wireless telemetry to obtain real-time downhole data during well construction operations. With an unprecedented rate at three orders of magnitude faster (57,600 bps) than wireless systems, networked drillstrings offer twoway broadband communication. In addition, real-time pressure and temperature measurements are uniquely available from multiple discrete measurement stations along the drillstring. Industry-wide adoption of this technology necessitates the system to lower well construction expenditure through increased efficiency, improved wellbore quality and reduced risk exposure to be considered as a viable alternative to conventional strings. In addition, system reliability must be demonstrated with useful metrics. Mean Time Between Failure (MTBF) is one such metric used in the industry to measure reliability. High values of a system MTBF generally indicate a reliable product when combined with other metrics. This paper provides historical trends of MTBF, and other reliability metrics in the case of high-speed networked telemetry drillstrings. The data and most conclusions are based on a reliability study from 65 wells that were drilled from 2008 to 2011. Results show increasing trends in reliability. Future improvements to network drillstring are discussed and their effect on reliability through these estimates is forecasted.