Z is the oil super-compressibility factor, dimensionless.For most reservoir engineering calculations, the gas formation volume factor (and Gas Compressibility, c g, and Gas Density, ρ g) can be determined from the Real Gas Law, Equation 3.27: For natural gases we are also most interested in the Gas Formation Volume Factor, B g, and the Gas Viscosity, μ g, as these properties strongly influence gas storage (and accumulation) and gas flow.
