Anuário do Instituto de Geociências (Aug 2007)
Caracterização de Parâmetros Hidráulicos em Depósitos Fluviais Paleogênicos na Bacia de Volta Redonda, RJ.
Abstract
The present study aims for the characterization of the hydrogeological parameters of the Paleogenic fluvial deposits ofVolta Redonda Geological Basin, through hydraulic conductivity determinations and grain sized analyses. The overall goalwas to produce a hydrogeological data base applicable to the characterization of hydrofacies (interconnected sedimentarybodies with distinct hydraulic properties) and the modeling groundwater flow. The used methods used consisted of in situpermeability determinations (Guelph permeameters) and laboratory tests (variable head permeameter), besides grain sizeanalyses carried out in each sedimentary facies in the study area. These sedimentary facies were characterized by Marques(2006) and belong to the Resende and Pinheiral formations. The permeameter results were coherent to the sedimentologicalcharacteristics. The Resende Formation sedimentary deposits are constituted by medium to fine sand with presence of argillaceousmatrix and present moderate to very low hydraulic conductivity, varying between 10-4 to 10-8 cm/s, which indicatesa poor reservoir. The Pinheiral Formation presents sandy layers with conglomeratic lenses, limited by small thickness peliticintervals, with a very low permeability, with a hydraulic conductivity varying between 10-5 to 10-7 cm/s. The upper layer hasthe maximum permeability, around 10-3 cm/s. This formation presents a medium reservoir characteristics and it must be takeninto consideration that the upper layer has as role in recharge to the aquifer. From the results of hydraulic conductivity, thatvaries from 10-8 to 10-3 cm/s for the Resende and Pinheiral formations, it is concluded that these deposits a low to mediumhydraulic conductivity, explaining the low productivity of the water-bearing multilayered aquifer of Volta Redonda Basin.
