关键词: 水平井, 钻柱受力, 摩阻, 扭矩, 非线性, 有限元, 预测, 计算机, 软件

Abstract: This paper applies the non-linear finite element method to the prediction of the torque of the drill string and the drilling direction of the bit.Two non-linear problems are tackled, one being the large deformation of the string, the other the contact between the string and the wall of the wellbore.A group of equations are derived by the non-linear amalysis of the drill string, and the corresponding calculation software based on these equations are developed. The work of this paper has been successfully applied to the drilling practice in Weizhou, South China Sea, where Naihai West Oil Co., Ching National Offshore Oil Corporation, drilled 5 wells using the technique of this paper.

Key words: horizontal well, drill string force, friction force, torque, non-linear, FEM, prediction, computer, software