TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe Karachaganak gas condensate field in Kazakstan is a one of the largest gas condensate fields in the world. The success of the field development by pressure depletion depends on the mobility of the gas and condensate below dewpoint. An experimental programme is designed to generate phase relative permeabilities and quantify critical condensate saturations at different flow velocities and interfacial tensions. Accurate determination of fluid properties and interfacial tensions at reservoir conditions is essential to the optimisation of the depletion strategy and is strongly associated with the quality of the experimental coreflood data analysis and hence the results of reservoir performance predictions. This paper presents experimental measurements of pressure-volume-temperature properties of the gas condensate samples from a Karachaganak well. For the first time a relatively detailed comparative discussion is provided on usefulness of the three experimental methods for measurement of low interfacial tensions in gas condensates at reservoir conditions, viz. the drop-shape-based pendant and spinning drop methods, and a laser light scattering method. The laser light scattering technique appears to be the most suitable approach for the determination of low interfacial tension in terms of precision and operation. It has successfully been used to measure interfacial tensions for the Karachaganak gas condensate fluid at elevated reservoir pressures and temperatures.