Online Control of Stick-Slip in Rotary Steerable Drilling

Rotary Steerable System is the current state of art of directional steering systems which has been developed for well drilling to achieve high reservoir productivity and to improve accessibility of oil reservoirs in complex locations. This work presents an online control scheme for real time optimization of drilling parameters to maximize rate of penetration and minimize the deviation from the planned well bore trajectory, and stick-slip oscillations. Nonlinear model for the drilling operation was developed using energy balance equation, where rock specific energy is used to calculate the minimum power required for a given rate of penetration. A proposed mass spring system was used to represent the phenomena of stick-slip oscillation. Detailed mathematical formulation and computer simulation will be used for evaluation of the performance of the proposed technique.