Flow pattern and phase distribution at the multiphase pump unit and in the inflow and outflow for horizontal, inclined and curved pipings
Dr.-Ing. Alexander Scharf
Dr.-Ing. Tobias Rausch
If wellheads for natural gas or oil are operated in hostile areas, for example in large sea depths, then the multi-phase mixtures of oil, water, gas and sand cannot be separated immediately after withdrawal from the well. The mixture must be transported through pipes over partly large distances for further processing. The pressure gradient necessary for transport often exceeds the supply pressure at the wellhead. If this is the case, then particularly designed pumps are used for increasing the pressure. They are called multi-phase pump units and are of the positive displacement pump type, which operates with two parallel arranged and counter rotating screws. The supply pressure of large flow rates of multiphase fluid mixtures with extremely varying phase distributions can be increased up to 50 bar due to the special design.
The aim of this work is to develop a model for calculation of the operational behavior of the multiphase pump unit as a function of the expected conditions in the oil and gas field. In this model the fluid dynamic behavior is considered by formulation of the balance equations for the momentum-, heat- and mass transfer within the pump housing. Transient behavior of the pressure in the multiphase pump is affecting the thermodynamic equilibrium. This phenomena is considered by calculation of the mass transfer between the phases.
The work is done in close co-operation with the company Bornemann and to predict and physically interpret measured data of multiphase pump units.