Dynamic modeling and load transfer prediction of drill-string axial vibration in horizontal well drilling

A three-dimensional finite element dynamics model of drill-string is established considering dynamic friction model and buckling effect. The modified dynamics model is proved to have higher computational accuracy by laboratory experiment. A parameters study is conducted based on the dynamics model. Results show that the exciting force amplitude, drilling fluid density, axial force, friction coefficient, and drill-string dimension have significant effects on the friction reduction performance and effective propagation distance of axial vibration. A prediction model for vibration propagation distance is established, which facilitates efficient optimization of the axial vibration parameters in horizontal well drilling. This study can provide theoretical guidance for axial vi-bration to safely and efficiently reduce the sliding friction in exploitation of unconventional oil-gas reservoirs.