Output

$\begin{array}{l}p(z)\end{array}$

Fluid pressure $\begin{array}{l}p\end{array}$

Input

$\begin{array}{l}z\end{array}$	Elevation	$\begin{array}{l}\rho_0\end{array}$	Fluid density at Logging reference point $\begin{array}{l}z_0\end{array}$
$\begin{array}{l}z_0\end{array}$	Logging reference point (usually at surface)	$\begin{array}{l}c_0\end{array}$	Fluid Compressibility at Logging reference point $\begin{array}{l}z_0\end{array}$
$\begin{array}{l}g\end{array}$	Standard gravity constant

(1)	$\begin{array}{l}\displaystyle p(z) = p_0 \cdot \exp \left[ - \frac{\rho_0 \, g}{p_0} \cdot (z-z_0) \right]\end{array}$

where

$\begin{array}{l}z\end{array}$	Elevation	$\begin{array}{l}p_0\end{array}$	Gas pressure at Logging reference point $\begin{array}{l}z_0\end{array}$
$\begin{array}{l}z_0\end{array}$	Logging reference point (usually at surface)	$\begin{array}{l}\rho_0\end{array}$	Gas density at Logging reference point $\begin{array}{l}z_0\end{array}$
$\begin{array}{l}g\end{array}$	Standard gravity constant	$\begin{array}{l}c_0\end{array}$	Gas Compressibility at Logging reference point $\begin{array}{l}z_0\end{array}$

(2)	$\begin{array}{l}\displaystyle p(z) = p_0 \cdot \exp \left[ - \frac{M }{R \, T} \cdot (z-z_0) \right]\end{array}$

where

$\begin{array}{l}z\end{array}$	Elevation	$\begin{array}{l}p_0\end{array}$	Gas pressure at Logging reference point $\begin{array}{l}z_0\end{array}$
$\begin{array}{l}z_0\end{array}$	Logging reference point (usually at surface)	$\begin{array}{l}M\end{array}$	Gas molar mass
$\begin{array}{l}g\end{array}$	Standard gravity constant	$\begin{array}{l}T\end{array}$	Gas temperature
		$\begin{array}{l}R\end{array}$	Gas constant

Derivation

(3)	$\begin{array}{l}\displaystyle \frac{\rho_0}{p_0} =\frac{M}{R \, T}\end{array}$