Field Operational Problems due to Condensate Formation

Reservoirs are categorized to black oil, volatile oil, gas condensate, wet gas and dry gas reservoirs. Gas condensate reservoirs have more complicated performance than the other categories because possessing intermediate compositions leads to more complex thermodynamic and phase behavior. When the well bottom hole flowing pressure falls below the dew point, condensate liquid builds up around the well bore, causing a reduction in gas permeability and well productivity. Accurate forecasting of gas condensate well productivity usually requires fine-grid numerical simulation to model the formation of the condensate bank and to account for high velocity phenomena such as non-Darcy flow and changes in relative permeability at high capillary pressure.