Integrating Surface And Borehole Geophysics In Ground Water Studies - An Example Using Electromagnetic Soundings In South Florida

Borehole induction logs are used to calibrate surface induction soundings in units of pore water<br>salinity. This is accomplished by correlating water sample conductivity with the electrical<br>conductivity of the formation over the sampled interval. In addition to the hydraulic calibration of<br>the surface induction data, the analysis shows geophysical logs contribute to the interpretation of<br>the surface induction soundings in two other ways: 1) logs show that the constant conductivity<br>layer model most often used to analyze induction soundings is appropriate for the south Florida<br>study; and 2) several physically independent log measurements can be used to uncouple the<br>dependence of formation electrical conductivity on such parameters as salinity, permeability, and<br>clay mineral fraction. We conclude that geophysical logs have important applications in<br>formulating geophysical inversion problems and in defining quantitative relations between<br>geophysical measurements and hydraulic or water quality parameters of interest.