Roach plot for abnormally pressured gas reservoirs
Input(s)
\(p_{i} / Z_{i}\): Initial \(\mathrm{P} / \mathrm{z}\) Ratio (psi)
\(c_{t}\): Rock Compressibility (1/psi)
\(G_{p}\): Gas Produced (SCF)
\(G\): Gas in Place (SCF)
Output(s)
\(\frac{p}{Z}\): Current \(\mathrm{P} / \mathrm{z}\) Ratio (psi)
Formula(s)
\[
\frac{p}{Z}=\left(\frac{p_{i}}{Z_{i} * c_{t}}\right) *\left(1-\left(\frac{G_{p}}{G}\right)\right)
\]
Reference(s)
Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3, Page: 213 .