Fatigue Analysis of the Drill String According to Multiaxial Stress

Abstract:

To find out the cause for fatigue failure of a drill string used in oil field drilling, and considering the actual working conditions, axial, radial and circumferential cyclic stresses borne by the drill string in borehole of oil and gas well, fatigue strength of drill string is analyzed based on multi-axial fatigue assessment method. Then the formula to calculate the mean stress of multi-axial load of the drill string is obtained, and the formula serves as a method to calculate multi-axial fatigue life of the drill string, which has been verified through field data. It is realized that multi-axial stress has significant influence on drill string fatigue. When on drill string fatigue, Soderberg equation shall be employed to calculate the stress amplitude of drill string fatigue.

• Periodical: Advanced Materials Research (Volumes 418-420)
• Pages: 993-996
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.418-420.993
• Online since: December 2011
• Authors: Jian Bing Zhang, Xiang Hong Lv
• Keywords: Drill String, Fatigue Failure, Multiaxial Stress

References

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[2] Baragetti, S., and Clerici, P., 1999, "Structural Behavior of Drill Collar Threaded Connections Under Makeup and Axial Static Applied Loads," Test Report.