I want the vertical line between the two columns to appear above the color below header row. How can achieve that?
Thanks
\begin{table}[h!]
\centering
\mycaption[Shuaiba reservoir properties]{Shuaiba reservoir properties.}
\label{table:chp2:sec02:Shuaiba reservoir properties}
\begin{tabular}{c|c}
\multicolumn{1}{c}{\textbf{Reservoir}} & \multicolumn{1}{|c}{\textbf{Dome-shape fractured carbonate}}
\\
\midrule
\rowcolor{Gray}
Matrix Porosity
& $\sim 30 \%$ \\
Matrix Permeability
& 1 - 20 mD \\
\rowcolor{Gray}
Viscosity & 220 cp, $16^{\circ}$ API \\
Oil Saturation & $\sim 95 \%$ \\
\rowcolor{Gray}
Gas Oil Ratio & $\sim 10\, sm^3/m^3$ \\
\end{tabular}
\end{table}
\setlength\arrayrulewidth{1pt}
inside your table environment as discussed here: tex.stackexchange.com/a/168592/120578