USING NMPC BASED ON A LOW-ORDER MODEL FOR CONTROLLING PRESSURE DURING OIL WELL DRILLING

During petroleum well drilling operations, the pressure gradient in the well has to be maintained within the pressure restrictions of the formation. The well pressure can be controlled by restricting the drilling fluid flow through a choke valve at the top of the well. This paper proposes a closed-loop control algorithm using a finite horizon nonlinear model predictive control scheme based on a low order well model for this problem. The algorithm is tested on a rigorous high order model.