Phase Behavior of a Gas-Condensate/Water System

Summary Gas-condensate reservoirs are an essential part of Saudi Arabia's hydrocarbon resources. A good understanding of the effect of water on the phase-behavior properties of these hydrocarbons is essential for accurately forecasting the performance of the reservoirs with numerical simulators. In addition, the scaling and corrosion tendencies of the produced brine are strongly influenced by mass transfer with the hydrocarbon phase. This paper presents unique experimental phase-behavior data for a typical Saudi Arabian gas-condensate three-phase (aqueous/ condensate/gas) system. The objective of this work is to quantify the effect of the aqueous phase on gas-condensate fluid properties. The results show that appreciable amounts of carbon dioxide and methane are partitioned from the gas-condensate phase into the aqueous phase. Another important observation is the mass transfer of water into the condensate phase. The mass transfer between the condensate and aqueous phases results in a slight decrease in the gas/condensate ratio (GCR). The carbon dioxide in solution makes the brine acidic and can dissolve carbonate minerals from the formation (e.g., calcium carbonate). In addition, the acidic or sour brine will be quite corrosive. The experimental results are compared with equation-of-state (EOS) and other correlations published in the literature.