Drilling Trajectory Prediction Model for Push-the-bit Rotary Steerable Bottom Hole Assembly Article in Press

The study of rotary steering drilling technology is currently one of the hot topics in the drilling engineering field. It requires accurate well trajectory control instructions when rotary steerable tools were applied to achieve the well trajectory control goal. A drilling trajectory prediction model will benefit this progress. According to the continuous beam theory, a mechanical model of push-the-bit rotary steerable bottom hole assembly (RSBHA) was established to characterize the bit steering property. The relation of bit lateral force and bit tilt angle with the influencing parameters such as borehole parameters and drilling operation parameters was obtained. Then further considering the bit cutting anisotropy, the drilling trajectory prediction model was built which quantitatively estimated the variation of inclination and azimuth angle. The model calculation result showed a consistency with the field experimental data proving the prediction model reasonable in theory and feasible in engineering. This study could provide a guidance for selecting the steering parameters to meet the control goal.