New study shows how to predict accumulated drill pipe fatigue

Fatigue is a prevalent mode of failure for drill pipe used in directionally drilled wells. To avoid costly fatigue failures and establish proper inspection frequency, a program was initiated to monitor fatigue in a working drillstring. This article presents fatigue data gathered during the 20-well drilling program. This means of data collection, analysis of each individual drill pipe history and the application of this data to calculating fatigue damage are reviewed. Results have been used to develop a new approach for determining fatigue accumulation and inspection frequency for a drillstring.