THE GEOTHERMAL TWO-PHASE ORIFICE PLATE

Abstract

A real time measurement of the mass flow rate and enthalpy of two-phase wells is important for the management of geothermal development and monitoring individual well outputs. Existing techniques for measuring the output of two-phase wells are either expensive (separators), low in accuracy (tracer dilution) or require the geothermal well to be taken out of production (horizontal discharge) for testing. Several new real time two-phase flow measurement methods are being investigated using both laboratory and field testing. The two-phase orifice plate is the most widely examined method and has also been implemented in several geothermal fields worldwide.
In this work, geothermal field data was used to examine five existing correlations for two-phase flow measurement using the concentric sharp-edge orifice plat. These correlations are relatively complex and include several empirically derived and calibration parameters. A new simple correlation was developed which has similar accuracy to that of Helbig & Zarrouk (2012) for measuring two-phase flow using the orifice plate.