A comparison of numerical mode-matching techniques for the analysis of well-logging tools

Two numerical mode-matching (NMM) techniques are compared for the analysis of logging-while-drilling (LWD) tools within borehole crossing in geophysical formations. The logging tools as well as the borehole and the surrounding geophysical formation are modeled as a stratified medium in cylindrical coordinates. One NMM technique perform a vertical expansion of the fields and a mode-matching is used to incorporate the radial stratifications. In the second NMM formulation, the fields are first expanded in radial direction and subsequently matched along each axial boundary. We present validation results and a preliminary analysis of the accuracy of these two NMM approaches to model typical well-logging tools used for hydrocarbon exploration.