DOWNLOAD POSTER PDFThe goal of this research is to develop a real-time stability monitoring scheme of the bottom-hole-assembly (BHA) vibration in drill-string using highly efficient numerical analysis of the lateral wave information. Lateral vibrations are considered to be severely destructive to drill-string operations but lateral vibrations or waves cannot be detected on the surface due to the strong damping environment and its highly dispersive nature. On the other hand, axial acoustic waves have been constructively utilized to transmit information through drill-string. In this study, the drill-string is modeled as a linear beam structure under gravitational field effects. An iterative wavelet-based spectral finite element method is developed to obtain a high fidelity response. Its high computational efficiency and capability to parallel computing outperform other existing methods. Numerical simulations of the lateral wave propagation at the BHA are first conducted and a time-frequency analysis technique is applied to the response in order to identify the relationship between the position of the neutral point and the dispersive properties of the lateral wave. Next, axial acoustic wave propagation through the upper drill pipe is conducted to explore the banded transmission properties of the drill-string introduced by periodic joints. Based on the results, a new monitoring scheme is proposed to monitor the stability condition of the vibration of drill-string based on a combination of lateral wave analysis at the BHA and the axial acoustic telemetry technique.
