Abstract: A wide range of steam-water mixtures was discharged to the atmosphere through a 10.7 mm diameter orifice which was sharp-edged with a minuscule throat pressure tapping. The ratio of throat pressure to up-stream pressure was found sensitive to dryness fraction over the whole range studied from 0.03 to 1.0. The technique (employing large orifices) has the potential of identifying the unknown enthalpy of geothermal wells discharging large flows. Contrariwise, a nozzle (rounded entry orifice) was found remarkably _insensitive_ over most of the dryness range and hence is useless for such determinations; however, it can be used to measure the flow-rate when enthalpy is known.

Abstract: Discharging small flows (order of 1 t/h) from wells is known as bleeding and is to relieve the build-up of gas pressure at the wellhead and to arrest corrosion in the bore. First tests over a range of bleeding flows indicate it as a fruitful subject for study in that temperature and pressure measurements at the wellhead can indicate the well enthalpy and the non-condensible gas content of the production system. Because of environmental restrictions on testing with large discharges in the future, bleeding may soon be the only valid alternative for proving a well’s potential.