An Analysis of the Bottomhole Assembly (BHA) in Directional Drilling, by Considering the Effects of the Axial Displacement

摘要

The modeling of the bottomhole assembly (BHA) is an essential problem in directional drilling. Some basic equations for predicting the performance of the BHA are presented in this paper. These equations take into account the effects of the axial displacement. The method of weighted residuals and the Newton-Raphson iterations are used to compute the nonlinear effects of the deformation of the BHA. A computer program is developed for the analysis of the BHA in order to quantitatively predict the performance of the BHA in directional drilling. In addition, a case study is presented to evaluate the effect of the axial displacement in the governing equation on the performance of the BHA. It is concluded that this effect is so small, that it can be ignored in actual calculations, and in the design and operations pertaining to directional drilling.