Abstract
Managed pressure drilling (MPD) is emerging as a powerful technology for precise control of wellbore pressure within tight bounds. MPD comes in a number of variants, each taking a different approach to controlling pressure by creating a closed, pressurize mud circulation system. While MPD offers unprecedented pressure control capabilities, it creates operational complexity that renders many standard work flows unsuitable for reliable operation. This is because MPD requires that several tools (pumps, chokes, valves, etc) must be coordinated simultaneously, a task at which humans may not be particularly effective. A solution to this problem is the use of enabling automation tools. Such tools would reliably integrate MPD-related activities using a multi-level hierarchy, allowing humans to concentrate on higher-level decisions, while leaving the reliable execution of lowerlevel decisions to automation. In this paper a multi-level control approach of an MPD operation will be presented. The control hierarchy approach consists of three different levels of control; a feedback control level consisting of fast independent control loops, one supervisory control loop which coordinates the different control loops in an optimal way, and finally an optimization level which tries to meet operational targets while maximizing the economical aspects of the operation. The multi-level control approach will result in an autodriller system.
