# Time to the end of infinite-acting period for a well in a circular reservoir

## Input(s)

\(\emptyset\): Porosity (fraction)

\(\mu\): Viscosity \((\mathrm{cP})\)

\(\mathrm{c}_{\mathrm{t}}\): Total Compressibility \((1 / \mathrm{psi})\)

A: Well Drainage Area \(\left(\mathrm{ft}^{2}\right)\)

k: Permeability \((\mathrm{mD})\)

## Output(s)

\(t_{\text {eia }}\): Time to the End of Infinite-acting Period (h)

## Formula(s)

\[
\mathrm{t}_{\mathrm{eia}}=\frac{380 * \emptyset * \mu * \mathrm{c}_{\mathrm{t}} * \mathrm{~A}}{\mathrm{k}}
\]

## Reference(s)

Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1, Page: 50 .