Patent ID: 7363164

Claim:
A method of evaluating water saturation characteristics in a geological formation penetrated by a borehole and including injection fluid introduced into the formation by an external injection process performed upon the formation, said method comprising the steps of: conducting electromagnetic induction measurements of the formation in the vicinity of the borehole, the measurements being indicative of resistivity values of the formation; obtaining a value of total porosity for the formation; defining fractional volumes for each of clay bound water, free water, and irreducible water in the formation, wherein the free water volume accounts for injection fluid introduced into the formation; defining values of conductivity for each of the clay bound water, the free water, and the irreducible water in the formation; determining total water saturation in the formation from a relationship between values of total porosity and conductivity of the formation, and values of conductivity and fractional volume for each of clay bound water, free water, and irreducible water; and basing a drilling decision on the determined total water saturation.