Two trends in development and operations of offshore oil and gas installations give increased demand for real-time monitoring and control; number & reach of subsea tie-ins and emerging implementation of integrated operations solutions. Within integrated operations, remote operation and collaboration between onshore and offshore are key elements. Sophisticated monitoring and control applications for wells and pipelines have been available from several vendors for some time. However, these applications have generally been stand-alone expert applications connected to a single subsystem, for example, a slug control solution for pipelines located in the plant control system or a virtual flow metering system for wells located in the subsea (control) system. The usage and benefit of these systems have therefore been limited. This paper outlines how monitoring and control applications for gathering networks should be structured in an integrated operations framework, and which benefits this will give for operators.
Structuring of the different applications ensures that data from monitoring applications are easily available for a large group of users while ensuring that closed-loop control applications retains the robustness and security that is required. Furthermore, recent developments of the applications itself, partially made possible by the modern integrated operations system topology with increased data availability, provides additional functionality not only for expert users, but for generalists as well. Finally, synergies between different monitoring and control applications can give additional value to the users.
Control and monitoring for remote subsea field in an integrated operations framework offers benefits such as faster decision making processes, increased production, improved deduction testing, condition monitoring of sensors using a combination of virtual metering and process data.
The paper outlines the status and future development trends for control and monitoring applications for subsea fields, illustrates the value of the technology and gives recommendations for implementation.
The choice of manipulated inputs and measured outputs can be critical for the successful design of a control system. This is especially the case when designing stabilizing controllers for unstable, non-minimum phase systems, as unstable poles combined with unstable zeros and time delay can render stabilizing control very hard. Since the presence and location of unstable zeros and time delay usually depends on the choice of measurements and control actuators, a thorough analysis prior to the actual controller design is important. In this paper, a controllability analysis is performed on a pipeline-riser system with multiphase flow, where the design objective is to stabilize an unstable operating point to remove riser slugging.
The topic of this paper is the effect of stabilizing control on the remaining control problem. In many cases there is no effect. However, stabilization requires the active use of inputs, and the underlying unstable pole will appear as an undesirable unstable zero if we are concerned with input performance. The implications of this are clearly demonstrated on the application to stabilization of severe slugging in two-phase pipeline-riser systems. We find that a controllability analysis gives important information for measurement selection and performance limitations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.