Simulation of electromagnetic logging-while-drilling tools using vector finite element methods

A vector finite element method (FEM) combined with the algebraic multigrid (AMG) method and a multifrontal solver is used to simulate the response of a electromagnetic logging-while-drilling (LWD) tool in a three dimensional (3D) inhomogeneous medium. A layered medium with a dipping borehole and invaded zones is partitioned into tetrahedrons. Each tetrahedron has six vector edge elements. The algorithm is applied to simulate the shoulder effect, the dipping angle effect, the eccentric effect, and the borhole effect.