# Gas compressibility factor

## Brief

gas compressibility factor is the ratio of the Real Gas volume to the Ideal Gas volume, which is a measure of the amount that the gas deviates from the perfect behavior.

$z = \frac{Actual\ volume\ of\ gas\ at\ specified\ T\ and\ P}{Ideal\ volume\ of\ gas\ at\ same\ T\ and\ P}$ [1]
Z factor in the PVT Tool at www.pengtools.com

## Discussion

Dranchuk correlation is the default correlation for the gas compressibility factor in the PVT tool.

## Nomenclature

$P$ = Pressure, psia
$T$ = Temperature, °R
$z$ = Gas compressibility factor, dimensionless