Subsea multiphase boosting is a technology that is gaining interest from oil & gas operators and suppliers, offering a robust and effective means to improve production from new or aging reservoirs. As a consequence of increased complexity in subsea processing, the overall production system should be considered when designing the individual components. This includes the interaction of the multiphase pumping station with the upstream and downstream flowlines, well and topside process.
This paper presents a subsea multiphase boosting system design with integrated controls, covering key milestones towards system-level integration of all major processing equipment. Results of the complete subsea production system model, including the boosting station, flowlines and production area are presented.
In order to accurately capture the interactions between the subsea multiphase boosting station and the flowlines connected to it, a process simulator (K-Spice®) is linked to a multiphase pipe flow simulation tool (LedaFlow®). This integrated solution is subsequently linked to Matlab/Simulink for the development of control strategies. Traditionally process simulation modelling of rotating machinery has been limited to either compressors or pumps. For this project Kongsberg has developed a multiphase rotating machinery module in K-Spice® that allows for accurate performance predictions at varying gas volume fractions. The three inter-connected engineering tools allow for a realistic simulation environment, capturing complex interactions between the different processing components, the connected flow lines and controls. This enables the optimization of reliability, cost and performance of the complete production system.
Subsea systems and processing are gaining importance in the oil & gas industry, enabling the development of new resources or enhanced recovery on existing fields. Multiphase boosting technology is playing a key role in this development, allowing simplification and greater flexibility for subsea processing units. In response to the growing interest for multiphase boosting technology, GE Oil & Gas is working on the development of a subsea multiphase pumping station. This boosting station includes a multi-stage pump which tolerates a high gas amount at its inlet, thereby eliminating the requirement for separation and transit via two separate flowlines. This publication focuses on the system-level integration of the different components to maximize the value of the project. This integration is done both via a system-level optimization of the design of the individual components and via the design of system-level control strategies.