Water saturation and sand fraction determination from borehole resistivity imaging tool, transverse induction logging and a tensorial water saturation model

The total porosity the formation, (13), including a fractional volume of the shale (13), and a resistivity of the shale are determined (22), in a laminated reservoir including sands that may have dispersed shales therein. A tensor petrophysical model determines the laminar shale volume and laminar sand conductivity from vertical and horizontal conductivities derived from multi-component induction log data (10). The volume of dispersed shale and the total and effective porosities of the laminar sand fraction are determined using a Thomas-Stieber-Juhasz approach. Removal of laminar shale conductivity and porosity effects reduces the laminated shaly sand problem to a single dispersed shaly sand model to which the Waxman-Smits equation can be applied.