Definition - What does Compressibility Factor mean?
Compressibility Factor is the ratio of molar volume of gas to that of ideal gas. It is the measure of the amount a gas is deviating from its perfect behavior at similar pressure and temperature. It is an important thermodynamic property used to modify the law of ideal gas to account for the behavior of real gas. When the gas is closer to the phase change, the deviation of the gas from its ideal behavior turns out to be more momentous.
Petropedia explains Compressibility Factor
Natural gas which has a gas compressibility or deviation factor of 1 behaves in a similar manner like an ideal gas. It is represented by a symbol ‘z’ which is described in real gas equation of state as:
pV = znRT
If the factor cannot be measured then it can be estimated with the help of correlations. The values of factor (z) are correlated for the blends of reservoir gases over the temperature and pressure ranges detected in the well tests. It is also known compression factor or gas deviation factor.