When gas condensate reservoirs are developed by pressure depletion, retrograde condensation occurs at pressure below the dew point of the condensate gas reservoir. The minimum saturation required for the flow of condensate in reservoir rocks is so-called critical flow condensate saturation (CFCS). We often want to know how much the CFCS is, about this, some study indicates the CFCS is 30-50%. Yet, field experience indicates the CFCS at much lower saturation of around 10%, particularly in the presence of connate water. Although this may be ignored in laboratory studies, it could significantly contribute to recovery at field scale.

An experimental equipment by ultrasonic has been established in order to directly determine the CFCS in core at high pressure fluid system. At first, we verify the way by applying different kinds of porous media (no media, filling media and synthetic media) and test the saturated vapor pressure of CO2 in them, then we use two real gas condensate and two synthetic cores (one: porosity 37.1%, permeability 1.44 μm2, and another: porosity 38.6%, permeability 1.73 μm2) to determine the CFCS, we demarcate the connection between condensate saturation and ultrasonic signal and get the CFCS which one is 15%, another is 18%.

You can access this article if you purchase or spend a download.