Boundary Element Analysis of Galvanic Corrosion of Long Structure Buried in Soil with Gradient Electrical Conductivity

Abstract

A new boundary element method for analyzing the galvanic corrosion of a long underground structure such as a pipeline and an oil well casing was developed. A long underground structure is often buried in soil with non-uniform electric conductivity. In case where the conductivity change is distinct, the conventional multi-region method is useful, while it gives an unrealistic solution with discontinuous jumps for gradual change of conductivity. To overcome the difficulty, the fundamental solution for a field with linear change of conductivity was introduced by using the Fourier transform technique, and the polarization characteristics were formulated to express its continuous change. A few example problems were solved with this method to demonstrate its applicability and usefulness.