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Laboratory Multi-Stage Separator

The laboratory multi-stage separator (MSS) test is i essence the same as a differential liberation experiment, but with variation in the temperature as well as the pressure. The MSS test is emulating the separator process and was originally used to model the separator process, but like all the PVT experiments is now used to fit a fluid model the fluis system.


The procedure for the MSS experiment is shown as an animation and as a schematic below. A PVT-cell is fill with a single-phase fluid sample at the initial reservoir pressure and temperature. The PVT-cell volume is then expanded and cooled/heated to a new temperature, reducig the pressure. When the PVT-cell volume has reasched a certain value (pressure is equal to the first stage separator pressure), all the gas is removed (keeping the pressure contstant). This procedure is repated for all the separator stages.

Animation of multistage separator PVT experiment

Animation 1: Animation of a laboratory MSS procedure for a saturated reservoir oil.

Figure of multistage separator PVT experiment

Figure 1: Schematic of a laboratory MSS experiment for a saturated reservoir oil.


The main results of the MSS experiment is the separator GOR and formation volume factor as well as the separator densities. This data is particularly useful in EOS model development as it is the only data that spans all directions in p-T-z space.