While drilling a wellbore, the dynamics of a drill string are continuously influenced by the drilling process, the wellbore geometry and the geological conditions. The interaction between the drill string and its environment, in particular the interaction of bit and rock, causes several dynamic phenomena. Thus, the operating drill string experiences axial, torsional and lateral vibrations, which potentially induce malfunction. These vibrations and malfunctions usually occur on different time scales. In order to mitigate the drill string vibrations and to reduce malfunction probability and intensity, an adequately complex model of the drill string is required. In addition to this, an effective evaluation of the dynamics can only be carried out with effective simulation techniques in the time domain due to system non-linearity, e. g. due to the bit-rock interaction and the contact between borehole wall and drill string. A minimized computing time is found for dynamic analyses using parameter and sensitivity studies. In this work, an overview of the modelling and simulation techniques will be given in order to tackle the aforementioned problems and challenges. The techniques were developed and used in the context of gebo. Thereby, simulations of short-term dynamics will be shown including dynamical phenomena as stick-slip and whirl. Additional simulations show the drill string's internal loads during the drillingprocess and an estimated rate of penetration.
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