"""
PermTrack(args...)

Return Wyllie and Rose permeability correlation using either Timur or Morris coeficients as well as fluid type, oil or gas
``K=Cperm*\frac { { Phie }^{ Dperm } }{ { Sw }^{ Eperm } } ``

## coeficients
### Timur
Dperm=4.4
Eperm=2.0

For Oil
 Cperm=3400

For Gas
Cperm=340

### Morris
Dperm=6.0
Eperm=2.0

For Oil
 Cperm=65000

For Gas
Cperm=6500

## Example

```julia
k=PermWR(0.18,0.3;Fluid="Oil",Author="Timur")
```
"""

function PermWR(Phie,Swir;Fluid="Oil",Author="Timur")
    #https://www.spec2000.net/15-permwyllie.htm

    if (Author=="Timur")
        Dperm=4.4
        Eperm=2.0

        if (Fluid=="Oil")
         Cperm=3400
        elseif (Fluid=="Gas")
            Cperm=340
        end

    elseif (Author=="Morris")
        Dperm=6.0
        Eperm=2.0
           if (Fluid=="Oil")
         Cperm=65000
         elseif (Fluid=="Gas")
            Cperm=6500
        end

        end

    k=Cperm .* (Phie .^ Dperm) ./ (Swir .^ Eperm)
end
