Comparison of RES2DINV and Earth Imager Tomography with Litho-ground models of Hydrocarbon Contaminated Site in the Coastal Plain Sand of Niger Delta
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Oil spills over pervious soils usually seepinto the ground where they are concealed from visual assessment and remain a threat to public safety. Risk assessment, design and the remediation systems in such instances is precededby site characterization. This involves intrusive investigations such as boring which is often expensive and time consuming and expose the subsoil and groundwater to further contamination. Consequently, the cheaper cost-effective electrical resistivity methods are widely used in recent times. This paper compares two commonly used approaches and software of non-intrusive Electrical Resistivity Tomography (ERT), namely the RES3DINV and the Earth Imager in delineating contaminated areas. Soil sampling was conducted using augers to establish ground control and boundaries of distribution of hydrocarbon contamination. A criss-crossing network of VES was then acquired and analyzed using RES-3D and Earth-Imager software to generate geo-electric ground models. Resistivity signature for mature oil contamination was determined as cutoff and used to discriminate between hydrocarbon contamination and other geo-electric horizons. Results suggest that ERT with its minimum footprint and low cost can become a standard method for the assessment and delineation of hydrocarbon polluted site. On the whole, the Earth Imager produced more realistic comparisons with the lithologic model compared to the RES3DINV. Images produced by the RES3DINV models are too sharp at the edges and boundaries with trajectories that are considered unnatural.
Publication Info:
Author: Abam, T.K.S. , Giadom, F.D. , Mogaba, P.M. and Nwankwo, I.L.
Volume: 60
Issue: September
Published By: Journal of Mining and Geology Vol. 60(2) 2024. pp. 185 - 198 © Nigerian Mining and Geosciences Society (NMGS), 2024-09-01