Shut-in time for pressure build-up test (Dietz method)

Input(s)

$\emptyset$: Porosity (fraction)

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

$C_{A}$: Shape Factor (dimensionless)

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

$c_{t}$: Total Compressibility $(1 / \mathrm{psi})$

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

Output(s)

$t_{s}$: Shut-in Time (h)

Formula(s)

$$ t_{s}=\frac{\phi * \mu * c_{t} * A}{0.0002637 * C_{A} * k} $$

Reference(s)

Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1, Page: 63.