title: Nonlinear model predictive control of managed pressure drilling.
abstract: A new design of nonlinear model predictive controller (NMPC) is proposed for managed pressure drilling (MPD) system. The NMPC is based on output feedback control architecture and employs offset-free formulation proposed in [1]. NMPC uses active set method for computing control inputs. The controller implements an automatic switching from constant bottom hole pressure (CBHP) regulation to flow control mode in the event of a reservoir kick. In the flow control mode the controller automatically raises the bottom hole pressure setpoint, and thereby keeps the reservoir fluid flow to the surface within a tunable threshold. This is achieved by exploiting constraint handling capability of NMPC. In addition to kick mitigation the controller demonstrated good performance in containing the bottom hole pressure (BHP) during the pipe connection sequence. The controller also delivered satisfactory performance in the presence of measurement noise and uncertainty in the system.
authors.affiliation: Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X5. Electronic address: a.nandan@mun.ca.
authors.forename: Anirudh
authors.initials: A
authors.lastname: Nandan
authors.affiliation: Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X5. Electronic address: simtiaz@mun.ca.
authors.forename: Syed
authors.initials: S
authors.lastname: Imtiaz
keywords: Gas kick; Managed pressure drilling (MPD); Nonlinear model predictive controller (NMPC)