Vibration of drillstring was found responsible for the severe damage and premature failure of drillstrings during drilling the gas-bearing igneous formations in the Songliao Basin, China. The vibration significantly shortened the life of drillstrings and had a great impact on drilling performance in the area. The objective of this study was to identify the key factors affecting drillstring vibration and develop a control-mechanism to reduce the failure rate of drillstring.

This study investigated the combined effect of axial and torsional vibrations on the damage of drillstring. A computerized model was built to simulate loads from axial and torsional vibrations. An analytical method for predicting the fatigue life of drillstring was developed. The method uses the output from the computerized model. Engineering charts were also generated for typical drilling conditions. These charts have been adapted in a Drillstring Damage Control Program implemented in the Songliao Basin, China.

Keywords:
Drilling Equipment, Upstream Oil & Gas, criterion, drilling operation, stress intensity factor, axial, drillstring design, drillstring dynamics, displacement, initial crack length
Subjects:
Drillstring Design, Drill Bits, Drilling Operations, Drilling Equipment, Drill pipe selection, Torque and drag analysis, Drillstring dynamics
Copyright 2006, Society of Petroleum Engineers
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