Mechanical analysis of a dual derrick

Abstract

Dual derrick can greatly improve the efficiency of drilling operations in deep-water area. Analysis of various drilling processes such as single-well drilling, multi-well drilling, collaboration and parallel jobs using dual derrick frame, has been carried out in this research. Meanwhile, static analysis of dual derrick and the analysing of loading cases have been conducted, as well as the suffered stress of dual derrick under severe or normal drilling conditions. Modal analysis of dual derrick has been completed, also, dynamic equilibrium equations and the matrices of corresponding mass and stiffness have already been induced. Concerning the fact that higher modes have a slight impact on vibrations, eight low-level modes of vibration of dual derrick have been put forward, which turn out to match the optimised structure of vibration modes.