# Mudcake growth equation 2 - Formation invasion

## Input(s)

\(\varnothing_{\text {eff: }} \quad\) Effective Porosity (fraction)

\(f_{s}\): Mud Solid Fraction (fraction)

\(\varnothing_{c}\): Mudcake Porosity (fraction)

\(x_{f}\): Transient Invasion Front (in.)

\(x_{f, o}\): Initial Displacement, i.e., Spurt (in.)

## Output(s)

\(x_{c}(t)\): Mudcake Growth by time (in./s)

## Formula(s)

\[
x_{c}(t)=\left[\varnothing_{e f f} f_{s} /\left\{\left(1-\varnothing_{c}\right)\left(1-f_{s}\right)\right\}\right]\left(x_{f}-x_{f, o}\right)
\]

## Reference(s)

Chin, W. C. (1995). Formation Invasion, Page: 45.