Wax Precipitation in Gas Condensate Mixtures

Abstract

Summary Wax precipitation for gas condensate fluids was studied in detail with a thermodynamic model. It was found that the precipitated wax phase can exhibit retrograde phenomena similar to that in gas condensates. As a result of pressure decrease (at a constant temperature), the amount of precipitated wax may first increase, then decrease, then increase again. The effect of pressure on wax precipitation from gas condensates was also studied. Pressure often shows an opposite effect in wax precipitation to that in liquids; however, the pressure effect is not universal. The model used in this work accounts for both the Poynting correction term and the solid-state phase transitions. Incorporation of these effects reconfirms the suitability of the multisolid phase for wax-precipitation calculations (both the onset and the amount).