The process flow is starting by receiving oil from flowlines and flexible risers running from the producing well to riser terminations on the FPSO. From the risers, the well-stream is routed via the inlet manifold to the 1st stage separator. The well-stream normally consisting of gas, oil and produced water is separated into three phases in the 1st stage separator. The gas is routed to the gas treatment module, the produced water to further treatment and the produced oil is transferred to the 2nd stage separator for further gas removal and stabilizing. The 2nd stage separator has a reduced pressure thus releasing most of the gas still present in the crude oil. The gas from the 2nd stage is routed via a gas recompression unit back to the gas treatment module. Crude oil from the 2nd stage separator is drained into the cargo tanks.
The gas treatment module may be a gas compression for reinjection (as on FPSO Piranema Spirit), gas compression for export to a pipeline, or the gas may be used for “gas lift” to improve the well stream. Some of the gas will be used as fuel gas for power production.
The produced water is treated normally for reinjection into the reservoir. The treatment may include filtration, de-aeration, chemical treatment, etc.
A flare system is required for flaring gas in case of shutdown in the process systems or if any unexpected gas releases are experienced.
Both on the process side and on the utility side of the process deck a drain system is arranged to enable an operation with zero discharge.