PVT-Properties

Properties for the simulations used in this study were picked to resemble a North Sea oil. The input of the phase behavior for black-oil models is in terms of formation volume factors, B_j, component solubilities, R_i,j, and phase densities at standard conditions, $\bar{\rho}_j$,(1 atm and $15 ^\circ \rm C$). The insitu phase densities $\rho_j$, which are required for determining seismic properties, can always be recovered using

$$\rho_j = \frac{1}{B_j}\left(\bar{\rho}_j + \bar{\rho}_i R_{i,j} \right) \;\;.$$ (1)

Formation volume factors for oil and gas as well as the solubility of the gas component into the oil phase, R_g,o, generally denominated as R_s, are shown in Figure . The oil component was assumed to be present in the oil phase only (R_o,g = 0.0 for all pressures). The phase densities at standard conditions for oil, gas, and water were taken to be $\bar{\rho}_o = 876.2\;{\rm kg/m^3}$, $\bar{\rho}_g = 0.732\;{\rm kg/m^3}$, and $\bar{\rho}_w = 1024\; {\rm kg/m^3}$ respectively.

 

marcofig1
Figure 7 Oil and gas formation volume factors and gas solubility as a function of pressure. Solubility of oil into the gas phase was assumed zero. The water component is assumed present in the water phase only.