UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

Guest
2024-11-22 1:26
 HOME     CONFERENCES     SEARCH            LOGIN     NEW USER     IMAGES   


Conference: Bucharest University Faculty of Physics 2013 Meeting


Section: Atmosphere and Earth Science; Environment Protection


Title:
Indirect electrical resistivity method to investigate underground oil contamination


Authors:
Serban Adrian ,Florina Chitea


Affiliation:
University of Bucharest, Faculty of Physics, P.O.BOX MG-11, Magurele, Bucharest, Romania;

University of Bucharest, Faculty of Geology and Geophysics; INSTITUTE OF GEODYNAMICS, SABBA S. STEFANESCU


E-mail
serbanaddy@yahoo.com


Keywords:
electrical resistivity, oil contamination


Abstract:
Petroleum hydrocarbons with densities lower than 1g/cm3, classified as LNAPL (Light Non Aqueous Phase Liquids), migrates into the geological medium under gravity effect but also by underground water transportation. In the absence of remediation actions, the volume of soil affected expands (laterally and vertically). Where contaminant plume reaches the aquifer, direct investigation methods become difficult to apply and also expensive (as drilling boreholes for soil and water probes extraction are needed). In such cases, indirect study methods are the best way to localize, delimitate and characterize the contaminated area. This paper present a case study of an indirect investigation method applied in the vicinity of Petrobrazi Rafinery (Ploiesti City). Electrical resistivity measurements consisting in Vertical Electrical Sounding were executed along profiles crossing the south-east trending of contaminant plume. This method is based on determining soil apparent resistivity by using direct current (DC) or a low frequency alternating current (AC) injected into the soil. As crude oil and oil derivate products are characterized by high electrical resistivity values, and considering Archie’s Laws, polluted areas are expected to determinate high resistivity anomalies. The instruments employed for measurements were SAS 300 and SAS 4000 (ABEM) resistivity meters. VES measurements were executed in stations whit a maxim depth of investigation of 50m (expressed in terms of injection line extend -AB/2). From VES curves and resistivity sections the thickness of contaminated layers can be estimated. The relative large contaminated volume of rocks is due to the contribution of fresh spills, past contamination and water table oscillations. Acknowledgements Field activity for detection of the underground oil contamination in the Ploiesti area, were supported by the Ministry of Education and Research, within the scientific project CEEX 727 and PNII 244.