Difference between revisions of "Prats effective well radius"
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==Prats effective well radius equation== | ==Prats effective well radius equation== | ||
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| + | [[File:Prats effective well radius.png|thumb|right|400px|Prats effective well radius]] | ||
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| + | Effective well radius is a radius value at which well is draining the reservoir under the radial flow conditions. | ||
| + | *For stimulated wells the effective well radius is higher than the wellbore radius. | ||
| + | *For damaged wells the effective well radius is lower than the wellbore radius. | ||
| + | *For undamaged wells the effective well radius is equal to the wellbore radius. | ||
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| + | :<math>r_{w_{eff}}=r_w e^{-S}</math> | ||
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{{Quote| text = It appears that the behavior of vertically fractured reservoirs can be interpreted in terms of simple radial-flow reservoirs of large wellbore. | source = Prats, 1961}} | {{Quote| text = It appears that the behavior of vertically fractured reservoirs can be interpreted in terms of simple radial-flow reservoirs of large wellbore. | source = Prats, 1961}} | ||
| − | + | ===Skin equation for fractured wells=== | |
| − | + | For high conductivity fracture: | |
| + | :<math>r_{w_{eff}} = \frac{X_f}{2}</math> | ||
| + | and | ||
:<math>S = ln \left ( \frac{r_w}{r_{w_{eff}}} \right ) = ln \left ( \frac{2 r_w}{X_f} \right )</math> | :<math>S = ln \left ( \frac{r_w}{r_{w_{eff}}} \right ) = ln \left ( \frac{2 r_w}{X_f} \right )</math> | ||
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| + | ==Nomenclature== | ||
| + | :<math>r_{w}</math> = wellbore radius, length | ||
| + | :<math>r_{w_{eff}}</math> = effective well radius, length | ||
| + | :<math>S</math> = skin factor, dimensionless | ||
| + | :<math>X_f</math> = fracture half length, length | ||
==References== | ==References== | ||
Latest revision as of 06:39, 28 April 2020
Contents
Prats effective well radius equation
Effective well radius is a radius value at which well is draining the reservoir under the radial flow conditions.
- For stimulated wells the effective well radius is higher than the wellbore radius.
- For damaged wells the effective well radius is lower than the wellbore radius.
- For undamaged wells the effective well radius is equal to the wellbore radius.
It appears that the behavior of vertically fractured reservoirs can be interpreted in terms of simple radial-flow reservoirs of large wellbore.— Prats, 1961
Skin equation for fractured wells
For high conductivity fracture:
and
Nomenclature
= wellbore radius, length
= effective well radius, length
= skin factor, dimensionless
= fracture half length, length
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.
