Finite Element Modeling of Drillstrings

Abstract

A finite element model is presented for investigating dynamic behavior of drillstrings used in oil and gas wells. A Timoshenko beam element is used to model axial and transverse vibrations. The effect of axial load, gravity, the constraints due to stabilizers are considered. The results show that a small amount of disorder in the configuration as well as the gravity cause strong mode localization which may be catastrophic. The implications for design and operation in the presence of mode localization is also discussed.