Robust computation of geoelectric potentials in cylindrically stratified anisotropic Earth formations

A robust semianalytical algorithm for the efficient computation of geoelectric potentials due to current electrodes in cylindrically stratified anisotropic media is discussed. The underlying analytical formulation is designed to eliminate the poor scaling of the modified Bessel functions for extreme orders and/or arguments, and to stabilize the potential evaluation in double-precision arithmetic for a wide range of input parameters. In addition, extrapolation methods are judiciously employed to accelerate the numerical integration. The algorithm is verified in several scenarios involving cylindrically stratified media of practical interest to geophysical exploration, in which input parameters (layer resistivities) can vary over many orders of magnitude.