SOLUTION NONUNIQUENESS FOR SEPARATED GAS–LIQUID FLOW IN PIPES AND WELLS. II. ANALYSIS

ABSTRACT

As shown in [10], multiple solutions may occur for upward flow for separated flow in a pipe without wall mass transfer. For the wellbore flow with wall inflow (production well) case, multiple solutions only exist for upward flow for the gas inflow-dominant case, whereas they may exist for upward, horizontal and downward flow for liquid inflow-dominant situations. The opposite is expected for the wall outflow (injection well) case. The transient models have been proposed for separated (stratified and annular-mist) gas–liquid flow in pipes or wells and successfully applied to validate, both physically and numerically, the correct solution of liquid holdup and pressure drop whenever multiple solutions exist for separated flow. Physical considerations and numerical simulation have shown that only the solution with the lowest liquid height (holdup) is physically realistic. The solutions corresponding to the intermediate and the highest liquid holdup may not be able to lead to a stable flow.

ACKNOWLEDGEMENT

We gratefully acknowledge the financial support from the Stanford University Petroleum Research Institute's Reservoir Simulation Industrial Affiliates Program (SUPRI-B), the Stanford Project on the Productivity and Injectivity of Horizontal Wells (SUPRI-HW), and the US DOE under contract #DE-FG22-93BC14862. We also thank Mr. Nicholas Petalas for helpful comments.

Notes

*The interfacial level gradient refers to the pressure variation due to the change of the liquid level along the pipe axial direction.