Advanced control of managed pressure drilling

Automation of managed pressure drilling (MPD) enhances the safety and increases efficiency of drilling and that drives the development of controllers and observers for MPD. The objective is to maintain the bottom hole pressure (BHP) within the pressure window formed by the reservoir pressure and fracture pressure and also to reject kicks. Practical MPD automation solutions must address the nonlinearities and uncertainties caused by the variations in mud flow rate, choke opening, friction factor, mud density, etc. It is also desired that if pressure constraints are violated the controller must take appropriate actions to reject the ensuing kick. The objectives are addressed by developing two controllers: a gain switching robust controller and a nonlinear model predictive controller (NMPC). The robust gain switching controller is designed using H1 loop shaping technique, which was implemented using high gain bumpless transfer and 2D look up table. Six candidate controllers were designed in such a way they preserve robustness and performance for different choke openings and flow rates. It is demonstrated that uniform performance is maintained under different operating conditions and the controllers are able to reject kicks using pressure control and maintain BHP during drill pipe extension. The NMPC was designed to regulate the BHP and contain the outlet flow rate within certain tunable threshold. The important feature of that controller is that it can reject kicks without requiring any switching and thus there is no scope for shattering due to switching between pressure and flow control. That is achieved by exploiting the constraint handling capability of NMPC. Active set method was used for computing control inputs. It is demonstrated that NMPC is able to contain kicks and maintain BHP during drill pipe extension.

Acting on impulse: using the neuroscience of impulse control to improve the law

This thesis investigates the potential legal utility of neurotechnologies which measure correlates of impulsive behaviors. Chapter 1 explains my philosophical position and how this position compares to others in the field. Chapter 2 explores some of the technical concepts which must be understood for the discussion of neurotechnologies and their applications to be fruitful. These chapters will be important for both explaining the capabilities of a neuroscientific approach to neural abnormalities as well as how they relate to the kind of regulation in which the law is engaged. The purpose of Chapter 3 will be a descriptive account of Canadian law where I will begin to explore how to apply ideas and experiments from neuroscience to specific areas of law. Chapter 3 will look at actual examples of Canadian criminal law and will span topics from the creation of law to the construction of appropriate sentences. Chapter 4 will debate if and how we should apply the neuroscientific perspective to the law given the ethical concerns surrounding the applications described in Chapter 3. The thrust of the chapter is that the development of the law does not occur in a vacuum and any alteration either to the laws themselves, how they are interpreted, or the technologies used to provide evidence, must have an ethical justification, that is, a way in which the proposed change will better meet the needs of society and the ethical objectives of the law. Sometimes these justifications can be drawn directly from constitutional documents, such as the Charter, or from the Criminal Code, while at other times these justifications depend upon arguments about furthering meaningful responsibility and therapeutic outcomes.