Control-Oriented Modeling for Managed Pressure Drilling Automation Using Model Order Reduction

Abstract

Automation of managed pressure drilling (MPD) enables fast and accurate pressure control in drilling operations. The performance that can be achieved by automated MPD is determined by, first, the controller design and, second, the hydraulics model that is used as a basis for controller design. On the one hand, such hydraulics model should be able to accurately capture essential flow dynamics, for example, wave propagation effects, for which typically complex models are needed. On the other hand, a suitable model should be simple enough to allow for extensive simulation studies supporting scenario analysis and high-performance controller design well. In this paper, we develop a model order reduction approach for the derivation of such a control-oriented model for single-phase flow MPD operations. In particular, a nonlinear model order reduction procedure is presented that preserves key system properties such as stability and provides guaranteed (accuracy) bounds on the reduction error. To demonstrate the quality of the derived control-oriented model, comparisons with field data and both open-loop and closed-loop simulation-based case studies are presented.