<p>Aiming at the vibration problem of drilling string system in ultra-high temperature and high pressure (ultra-HPHT) curved well, the finite element method, energy method and Hamiltonian principle are adopted to establish the four-dimensional nonlinear vibration model of the whole well section drill string system. The influence of wellbore trajectory change, wellbore constraint, interaction between bit and rock, and the influence of ultra-high temperature and high pressure on the elastic modulus of string and drilling fluid viscosity are considered. Based on the discretization of the control equation by Lagrange and cubic Hermite functions, and the joint iteration of the incremental form of Newmark and Newton Raphson, the numerical solution of the four-dimensional nonlinear vibration model of the drill string system is realized. In order to effectively verify the correctness of the nonlinear vibration model of drill string system, a similar experiment of drilling string vibration is designed and completed to further test the validity of the four-dimensional nonlinear vibration model by comparing the frequency-domain and time-domain responses of the experiment with those from the model. The analysis shows that the four-dimensional nonlinear vibration model has good calculation accuracy and the vibration response law is basically consistent with the experimental results, which can provide an effective theoretical analysis tool for nonlinear vibration &nbsp;behavior of drilling string&nbsp;in ultra-HPHT curved well.</p>

Investigation on Axial-Lateral-Torsion Nonlinear Coupling Vibration Model of Drilling String in Ultra-HPHT Curved Wells

Paper Proceedings: https://asmedigitalcollection.asme.org/OMAE/OPTC2021/volume/85222

ASME 2021 Onshore Petroleum Technology Conference (OPTC2021)

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