Prediction of Condensate Formation in Gas-Condensate Reservoirs

Gas-condensate reservoirs exhibit complex phase and flow behaviors due to the appearance of condensate banking in the near well region and changing composition of each phase dynamically. A good understanding of the effect of the gas composition on the flow and phase behavior properties of these reservoirs is essential for carrying out accurate forecasts of gas condensate reservoirs behavior using numerical simulators. Natural production from these reservoirs leads to pressure drop of the reservoir which results in gas condensation and liquid dropout in the reservoir. The phenomenon exhibits itself in the vicinity of the wellbore first and then propagates in a cylindrical form to the reservoir volume. The most important effect of liquid condensation is the reduction of gas relative permeability and as the result the loss of production. A new compositional technique is used here to investigate the gas composition effects on the calculated relative permeability and hence the gas production.