ESTIMATION OF SOIL PETROPHYSICAL PARAMETERS FROM RESISTIVITY DATA: APPLICATION TO OIL-CONTAMINATED SITE CHARACTERIZATION

Abstract

Vertical Electrical Sounding (VES) method, known from 1912, has changed greatly during the last 10 years, into a new technology named Resistivity Imaging (RI) with 2D data interpretation. Another possible development for VES method is estimating petrophysical parameters (PP) from RI data, using the relationship between electrical resistivity and PP. In order to reach this purpose, the theory of the forward and inverse problem that relates the electrical resistivity with PP was developed. Each field survey should include a VES (RI) survey, groundwater resistivity measurements in order to determine the groundwater salinity, and collecting some representative soil samples in the study site for resistivity measurements as function of pore water salinity in laboratory, creating a soil petrophysical model of the site. This technology can be used for the characterization of uncontaminated and oil contaminated sites. For the case of contaminated site PP values determined in laboratory, groundwater salinity and RI data help to define the petrophysical boundary between contaminated and uncontaminated soil, and consequently, to obtain the contamination plume. In this work, the results of the application of this technology in some hydrocarbon contaminated sites in Mexico are presented.