Geoelectrical characterization of an oil-contaminated site in Tabasco, Mexico

Abstract

A geoelectrical characterization of an oil-contaminated site, where thirty years ago an oil well was drilled, was carried out using vertical electrical sounding (VES) method on 2D Resistivity Imaging technology and 2D interpretation. VES data were added by water resistivity measurements and soil resistivity analysis. The contaminated zones feature with low resistivity anomalies situated above groundwater level. The geoelectrical interpretation was compared with geochemical sampling. An inverse correlation between electrical resistivity and concentration of contaminants confirms that the oil-contamination is mature and for this reason it creates low resistivity anomalies. Petrophysical modelling allowed estimating boundary resistivity value separating clean and contaminated zones. Resistivity data were visualized as cross-sections and maps and also were recalculated into sections and maps of petrophysical parameters, useful for more precise and detailed characterization of contaminated zones.