Brief notes on the CREWES Fluid Property Calculator

This Calculator is designed to produce information on pore fluids of interest in petroleum exploration. It is intended for use in connection with seismic fluid substitution operations.

The Gas Phase calculations may be carried out in either of two ways. Those using mole fraction input employ the Peng-Robinson equation of state in order to calculate acoustic properties. Those using the gas density ratio as input employ empirical relations described by Batzle & Wang (1992). Viscosity is calculated only by the empirical equation route.

The Liquid Phase calculations employ empirical relations which are based on Batzle & Wang, but which vary slightly from them for some of the properties:

The Brine Phase calculations also employ empirical relations as given by Batzle & Wang.

The Multi-Phase calculations employ simple volume fraction averaging for the density and Wood's relation for the bulk modulus. The velocity is calculated from the resulting density and bulk modulus. The viscosity is not calculated in the multi-phase case.

For questions or suggestions regarding this applet, contact


  1. Batzle, M. and Wang, Z., 1992, Seismic properties of pore fluids: Geophysics, 57, 1396-1408.
  2. Peng, D.-Y. and Robinson, D. B., 1976, A New Two-Constant Equation of State: Ind. Eng. Chem., Fundam., 15, 59-64.
Copyright, 2015, CREWES, University of Calgary