An enthalpy model of CO2-CH4-H2S-N2-brine systems applied in simulation of non-isothermal multiphase and multicomponent flow with high pressure, temperature and salinity

An accurate enthalpy model for CO2-CH4-H2S-N-2-brine fluid system is proposed in this work. For the gas system (CO2-CH4-H2S-N-2), the model is based on Peng-Robinson EOS enthalpy deviation to calculate real gas system specific enthalpy. For the brine system, the model extends conventional saturation state enthalpy model considering pressure effect along with the temperature and salinity effects. For the dissolution heat, the model combines phase equilibrium parameters to describe the gas dissolved enthalpy. The model can predict CO2-CH4-H2S-N-2-brine fluid system enthalpy well with temperature range from 0 to 300 degrees C, pressure range from 0 to 1000 bar and salinity range from 0 to 6 mol/kg water. The model performs favorable with respect to existing experimental data and other models and reproduces reliable data for pure water, various salinity of brine and gas systems.