Radius of investigation (shut-in time)

Input(s)

$\mathrm{dt}$: Time of shut in (h)

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

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

$\varnothing$: Porosity (fraction)

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

Output(s)

$r_{i}$: Radius of investigation $(\mathrm{ft})$

Formula(s)

$$ r_{i}=\left(k^{*} \frac{d t}{948 * \varnothing * \mu * c_{t}}\right)^{0.5} $$

Reference(s)

Pressure Buildup and Flow Tests in Wells, Matthews \& Russell, Page: 117.