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.