Free gas in place
Input(s)
A: Drainage Area (acres)
\(\mathrm{h}\): Thickness \((\mathrm{ft})\)
\(\varnothing\): Porosity (fraction)
\(\mathrm{S}_{\mathrm{wi}}\): Initial Water Saturation (fraction)
\(\mathrm{E}_{\mathrm{gi}}\): Gas Expansion Factor at Initial Reservoir Pressure \((\mathrm{SCF} / \mathrm{bbl})\)
Output(s)
\(\mathrm{G}_{\mathrm{f}}\): Original Free Gas-in-Place \((\mathrm{SCF})\)
Formula(s)
\[
\mathrm{G}_{\mathrm{f}}=7758 * \mathrm{~A} * \mathrm{~h} * \emptyset *\left(1-\mathrm{S}_{\mathrm{wi}}\right) * \mathrm{E}_{\mathrm{gi}}
\]
Reference(s)
Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3, Page: 227.