Geothermal Two-Phase Wellbore Flow: Pressure Drop Correlations and Flow Pattern Transitions

In this paper we present some basic concepts of two-phase flow and review the Orkiszewski (1967) correlations which have been suggested by various investigators to perform well for geothermal wellbore flow situations. We also present a flow regime map based on the transition criteria used by Orkiszewski (1967) and show that most geothermal wells flow under slug flow regime. We have rearranged bubble- to slug-flow transition criterion used by Orkiszewski (1967) to show that the transition depends on the dimensionless pipe diameter number in addition to dimensionless liquid and gas velocity numbers. Our aim is also to identify what research may lead to improvements in two-phase pressure drop calculations for geothermal wellbore flow