This paper presents the development of a new bottomhole assembly (BHA) program and how it is used to deliver optimal BHA design. The new program allows users to run static and dynamic models in the same application which will save time and minimize errors. For the static model, the program uses the newly developed generic algorithm for solving the Lubinski's BHA equations directly. The strengths of the new algorithm are accuracy and computation efficiency, as compared to the conventional finite-element based BHA programs. In addition, the program is designed to run fast on a personal computer (PC) with an intuitive user interface so that it can be used to optimize BHA design in the office as well as at the rig site.
The static model is primarily designed for directional drilling applications, such as optimal BHA design for maximum steerability, bending moment calculations to minimize fatigue failure, and BHA sag corrections to improve survey quality. The dynamic model is based on a hybrid of analytical and finite-element methods to calculate the critical rotary speeds of the BHA. This paper describes the significance of applying these features in a user-friendly application to improve the optimization process and maximize drilling performance.