Equivalent formation water resistivity from SP log
Input(s)
\(\mathrm{R}_{\text {mfeq }}\): Equivalent Resistivity of Mud Filtrate (ohm m)
SSP: Static Spontaneous Potential (mV)
\(\mathrm{T}\): Temperature \((\mathrm{F})\)
Output(s)
\(\mathrm{R}_{\text {weq: }}\): Equivalent Formation Water Resistivity (ohm m)
Formula(s)
\[
\mathrm{R}_{\mathrm{weq}}=(-61+0.133 * \mathrm{~T}) * \frac{\mathrm{R}_{\mathrm{mfeq}}}{10^{-\frac{\mathrm{SSP}}{61+0.133 * \mathrm{~T}}}}
\]
Reference(s)
Core Laboratories. 2005. Formation Evaluation and Petrophysics, Page: 74.