Case Study: Drillstring Failure Analysis and New Deep-Well Guidelines Lead to Success

摘要

Three drillstring fatigue failures occurred while drilling two deep wells below 16,500 ft true-vertical depth (TVD) in the U.S.A. midcontinent region. All the failures occurred across 2°/100 ft to 3°/100 ft dogleg severity intervals from 6,000 ft to 8,000 ft. The well conditions (i.e., pipe condition and directional plan) were not significantly different from other deep wells in the area, which had not failed. A deep-well drillstring failure study was conducted which included a review of drillstring inspection reports, daily drilling reports, digital data, technical literature, and engineering analysis for the two wells.