A modification to the Coates-Timur relationship to produce a more coherent relationship applicable to carbonate formations is disclosed. In this method, permeability may be determined using porosity and the ratio of bound fluid volume to (1—bound fluid volume). This method also allows for improved estimation of irreducible water saturation of a carbonate formation using the ratio of k^c and (e^f+k^c). Likewise, the bound fluid volume of a carbonate formation may be determined using the ratio of k^c and (e^f+k^c). In these relationships, e, x, and f are constants according to the following relationships e=x^c, f=bc+1, x is between 1 and 100 mD (preferably 10 mD).