(1)	$\begin{array}{l}\displaystyle k_{rgw}(s_g) = k_{rgwc} \, \bigg[ \frac{ s_g - s_{grw} }{ 1- s_{wi} - s_{grw} } \bigg]^{n_{gw}}\end{array}$

(2)	$\begin{array}{l}\displaystyle k_{rwg}(s_w) = k_{rwgc} \, \bigg[ \frac{ s_w - s_{wcg} }{ 1- s_{wcg} - s_{grw} } \bigg]^{n_{wg}}\end{array}$

current gas saturation, $\begin{array}{l}s_o = 1 - s_w\end{array}$

current water saturation, $\begin{array}{l}s_w = 1 - s_o\end{array}$

below which gas is immobile

critical water saturation to gas displacement,

below which water is immobile

where $\begin{array}{l}s_{wi}\end{array}$ is initial water saturation which maybe equal to critical $\begin{array}{l}s_{wсg}\end{array}$ or less than critical $\begin{array}{l}s_{wi} < s_{wcg}\end{array}$ like for example in petroleogenetic rocks.

The model assumes no oil presence in pores.

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See also