Modeling of well logging tools in a multibed environment with invasions

Abstract

A numerical mode matching method is presented for the analysis of wave propagation in multibed environments with invasions. An invaded multibed environment is modeled as a multiregion, cylindrically stratified medium. The scattering of electromagnetic waves by this inhomogeneous medium is analyzed by mode matching on the interfaces of the bed boundaries. The eigenmodes of each region of cylindrically stratified medium are found by using one-dimensional finite element method, providing the flexibility of the method, while the mode matching on the interfaces of the bed boundaries is performed by introducing the reflection and transmission operators, and generalized reflection operators. Since the unknowns in this problem are only in one dimension (i.e., on the interfaces of the bed boundaries), this method is shown very efficient compared to the conventional two-dimensional finite-element method. Some numerical results are presented.