Prats effective well radius

Prats effective well radius equation

It appears that the behavior of vertically fractured reservoirs can be interpreted in terms of simple radial-flow reservoirs of large wellbore.

— Prats, 1961

$r_{w_{eff}}=r_w e^{-S}$

where

$S = ln \left ( \frac{r_w}{r_{w_{eff}}} \right ) = ln \left ( \frac{2 r_w}{X_f} \right )$

References

Prats, M., Hazebroek, P., and Strickler, W.R. 1962. Effect of Vertical Fractures on Reservoir Behavior--Compressible-Fluid Case. SPE J. 2 (2): 87-94.