Finite element modeling of 3-D DC resistivity using locally refined unstructured meshes

Abstract

This paper briefly reviewed the disadvantages of commonly used structured meshes in geophysical fields. We introduced a new unstructured mesh based on Delaunay refinement algorithm to efficiently approximate the geometrically complex model boundaries. Additionally, we proposed a new local nodal refinement method. Based on Our new algorithm, we have implemented the automatic mesh generation on complex geological models by unstructured mesh and also offered the highly accurate numerical solutions in 3D DC resistivity problem. The final numerical solutions show that the singularity effects of current source point can be efficiently avoided and the new local nodal refinements approach can efficiently upgrade the accuracy of numerical solutions. Therefore, we can conclude that the new local refinement is nearly optimal and its combination with second order mesh can give us very accurate numerical solutions.