Tese: Nonlinear Dynamic Behavior of Oil-Well Drill Strings
Aluno(a) : Luiz Pereira Aguiar NetoOrientador(a): Ivan Menezes e Ludimar de Aguiar
Área de Concentração: Mecânica Aplicada
Data: 07/10/2021
Link para tese/dissertação: https://doi.org/10.17771/PUCRio.acad.56800
Resumo: This work studies the nonlinear dynamic behavior of oil well drillstring, which is a long slender flexible structure responsible for the drilling. Its elements and functions are presented, and numerical analyses are performed later. The work develops a computational code using the software MATLAB® for the numerical simulation of the column’s dynamic behavior using the finite element method. The corotational formulation is used for the implementation of geometric nonlinearity. The structure's discretization uses a beam element with six degrees of freedom per node and employs Euler-Bernoulli’s beam formulation. The Newton-Raphson method is responsible for solving the nonlinear system of equations. In addition, the solution procedure users the Newmark method for the time integration of the problem’s movement equations. A linear setup spring model is proposed to represent the contact between the borehole wall and the column. The proposed methodology and computational code capabilities are evaluated by comparing some results to analytical or numerical results of examples available in the literature. These results give reliability to analyze drillstring problems, which present the displacements and forces time series of the whole column and the buckling modes generated. The results show that the column is very sensitive to any boundary condition changing, which corroborates the complexity of the problem. Hence, the work proposes a reasonable basis for further developments, allowing the entire coupled drillstring analysis.