A new liquid hold-up correlation is devised for cased wellbores using high-quality discharge and downhole pressure and temperature data from flowing geothermal wells. The latter dataset encompasses a wide range of wellbore diameters, discharge rates and flowing enthalpies. The measured wellhead pressures for wells in the dataset display excellent agreement with the pressures computed by using the new hold-up con-elation. Good agreement between the computed and observed spinner responses provides additional verification of the hold-up correlation. Finally, an example illustrating the use of the hold-up correlation to match downhole pressure and temperature profiles and well characteristic data is given. (C) 2004 CNR. Published by Elsevier Ltd All rights reserved.