Development of a digital twin based real-time drilling optimization and control system

Abstract

The Oil and Gas industry suffers from a unique problem. The activity of the industry, and subsequently the retention of highly qualified personnel is closely tied to the oil price. Economic factors that are beyond the control of operators, govern the experience level of employees in all levels of the industry. The recent development of digital technologies presents an excellent opportunity for the industry to overcome the loss of experience accompanied by every downturn, and the increased rate of incidents accompanying every resurgence. This thesis consists of four articles discussing two different topics. These include i) developing a digital twin-based drilling optimization and control system, and ii) developing laboratory facilities for validating field scale experiments. The first article presents the theoretical development of a digital twin-based control system for drilling rigs. It starts with how the industry evolved the concepts of integrated operations, and real time support centers, and follows by how to construct the proposed digital-twin-based automation solution. The second article expands on a single component of the digital twin-based system. It discusses the development of an auto driller system based on optimal control theory. The article consists of an extensive literary review of drilling optimization, followed by developing a modified version of mechanical specific energy to be used as an objective function, development of a simple drilling model to be used as part of the controller, and development of a model predictive controller that optimizes the selection of drilling parameters. The model predictive controller was shown to be successful through simulations but had some performance limitations due to the complexity of the bit rock coupling term in the drilling model. The third and fourth articles discuss the development of a hardware in the loop drilling simulator. The articles describe the design of the system, the development of its operating systems, and experimental validation of its performance. The articles also discuss the development of Bond Graph models that were used for planning of experiments and components of the simulators control system. The thesis is concluded by recommendations on how to improve the proposed automation system and expand the capabilities of the simulator.