Experimental Investigation of Critical Flow Condensate Saturation

摘要

When gas condensate reservoirs are developed by pressuredepletion, retrograde condensation occurs at pressure belowthe dew point of the condensate gas reservoir. The minimumsaturation required for the flow of condensate in reservoirrocks 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 lowersaturation of around 10%, particularly in the presence ofconnate water. Although this may be ignored in laboratorystudies, it could significantly contribute to recovery at fieldscale.An experimental equipment by ultrasonic has beenestablished in order to directly determine the CFCS in coreat high pressure fluid system. At first, we verify the way byapplying different kinds of porous media (no media, fillingmedia and synthetic media) and test the saturated vaporpressure of CO2 in them, then we use two real gascondensate and two synthetic cores (one : porosity 37.1%,permeability 1.44μm2, and another : porosity 38.6%,permeability 1.73 μ m2) to determine the CFCS, wedemarcate the connection between condensate saturationand ultrasonic signal and get the CFCS which one is 15%,another is 18%.