Patent ID: 7295927

Claim:
A method to estimate total water saturation (S wt ) of a thin-bedded formation under investigation, comprising: a. expressing anisotropy of resistivity as R v /R h , wherein R v is the vertical resistivity and R h is the horizontal resistivity and wherein R v /R h is a function of total water saturation (S wt ) for one or more shale volume fractions (F shale ), and assuming the cementation and saturation exponent of the shale and sand layers is equal to 2, the fine-grain shale is fully saturated with brine, and the fine grain-shale layer porosity and the total bulk porosity of the stack are very close; b. measuring the anisotropy of resistivity of said formation under investigation; c. measuring the shale volume fraction of said formation under investigation; and d. wherein said method is used to estimate the total water saturation (S wt ) of said formation under investigation by correlating anisotropy of resistivity to said shale volume fraction of said formation, and produce water saturation data in a tangible form.