transform_direct.RdFunction to transform the apparent resistivity into effective resistivities which are assumed closer to the real resistivities using an exponential equation.
transform_direct(ves, k = 2.3, alpha = 0.15)
| ves | A ves object. |
|---|---|
| k | Empirical constant. |
| alpha | Decay exponent (pseudo-porosity factor). |
This function returns a list with the following entries:
depth: Depth
real.res: Real resisitivity
The conversion from apparent resitivities to effective resistivities is achieved using the following expression: $$ \rho_{eff}=k\rho_{app}\exp{(-(1-\alpha))} $$ where:
\(\rho_{eff}\) is the effective resistivity which is assumed to be closer to the true resistivity.
\(\rho_{app}\) is the apparent resistivity measured in the field.
\(k\) is a empirical constant defined to improve the fit between the apparent and effective resistivities. This constant has a value of 2.3.
\(\alpha\) is the exponent in the exponential relationship. Its value is of 0.15.
Meju, M. Simple effective resistivity-depth transformations for infield or real-time data processing. Computers and Geosciences, 21(8), 985-992, 1995.
Other transformation functions: transform_scaling,
transform_smoothed_zohdy,
transform_zohdy