The high-definition stratified flow model in Schlumberger's dynamic multiphase flow simulator has been applied in an ongoing project for Statoil, addressing the design of an offshore gas condensate field in Tanzania. The modelling work focuses on the prediction of the liquid accumulation, which defines the operational envelope of the system, the upscaling of numerical predictions and experimental data to field conditions, and the statistical representation of model uncertainties. A highly comprehensive data set was obtained by SINTEF in their Large Scale Loop at Tiller, covering liquid accumulation for very low liquid loading in two upwardly inclined 8- and 12-inch pipes. The high-definition model predicts the data well. Applying the data to tune the model improves "predictions" further. The accumulation data suggest a scale up from lab to field based on the gas Froude number and pipe angle. The retuned high-definition model agrees with this scaling, confirming that a similar scale up is inherent in the model. Finally, we demonstrate how to obtain robust statistical distributions for the closure parameters in the high-definition model, suitable for uncertainty studies.
This paper reports on some of the modelling work performed by Schlumberger SPT Technology Center (SPT TC) in an ongoing project for Statoil, addressing an offshore gas condensate field development in Tanzania, see Holm . The modelling, which uses the OLGA1 High Definition Stratified Flow Model (OLGA HD), see Biberg , focuses on the prediction of the liquid accumulation, which defines the operational envelope of the system, the upscaling of numerical predictions and experimental data to field conditions, and the statistical representation of model uncertainties.
A key challenge for Statoil's Tanzania field is the combination of low liquid loading and steep inclinations, which causes the flow to enter into a region of multiple holdup solutions. Accurate predictions of the associated liquid accumulation points where the holdup jumps from a low to high value are crucial, and will be considered in Sections 6 through 8.
SINTEF have conducted a highly comprehensive data gathering campaign in the Large Scale Loop at Tiller to support the project, as described in Kjølaas et al. . Simulation results covering the dynamic aspects of the experiments and their relation to the multiple holdup solutions for a fully developed steady state flow are reported by Staff et al. . An analysis of the experimental technique applied to obtain the accumulation point data is given in Nossen et al. .
1 Mark of Schlumberger