Active slug-control methods have been developed in recent years. One such system is a relatively inexpensive solution developed by Shell that has proved to be very effective in stabilizing slugging in flowlines and risers. Field data from case histories in the Gulf of Mexico (GOM), Malaysia, and Nigeria indicate that production gains of 10% are often possible.
The active slug-control method in question uses a single standard control valve and pressure sensors immediately upstream and downstream of the valve. One advantage of this method is that a choke/control valve is often already installed. If changes are required, these are often limited to the trim and actuator. Because only localized pressure measurements are required, this makes the technology a cost-effective solution with very limited added weight or space requirements. Another advantage is that the system acts on both liquid and gas surges of the multiphase fluid without the need for prior separation. It can thus stabilize the fluids arriving at the production facility, allowing for optimization and increased production.
In this paper, a new application in Nigeria is discussed in which this active slug-suppression technology reduced the gas and liquid surges and lowered riser gas lift requirements. Riser-base gas lift is often used both to reduce hydrostatic head and to mitigate slugging in subsea applications. In this case, the asset was gas lift constrained and the gas lift was insufficient to mitigate slugging below a fixed flow-rate range. Lowering gas lift requirements meant more barrels could be produced across the asset. Reducing slugging would enable lower minimal production limits....
Increasing Production by Applying Active Slug-Suppression Technology
10 October 2015