Evaluation of Subsoil Corrosivity Condition around Baracaia Area Using the Electrical Resistivity Method—A Case Study from the Muglad Basin, Southwestern Sudan

Abstract

This paper evaluate subsoil corrosivity using the electrical resistivity method which was carried out to determine the subsoil resistivity and estimate the degree of corrosion, the resistivity measurements were conducted by using SAS300c resistivity meter. This involves applying a voltage into the soil through metal electrode and measuring the resistance to the flow of electric current. An AC-power supplies current flow (I) between two outer electrodes and the resultant voltage different (V) between two inner electrodes is measured using the Wenner Arrangement. The soil resistance given by R = V/I. This needs to be standardized over a unit length, the resistivity ρ which measured in ohm-m the equation is, ρ = 2лdR. There are many factors control the ground resistivity such as soil composition, moisture content, pore water chemistry and pH. The results of the survey show inverse proportion between corrosivity and electrical resistivity, therefore resistivity method is very useful to incipient the corrosion as well as effective, quick, reliable and economic method. Structures such as natural gas, crude oil pipelines and steel constructions were reported to have been affected by soil corrosion all around the world, it can be concluded that sub soil corrosivity around the study area increases southwestern ward with depth.