Numerical Mode-Matching Method for Tilted-Coil Antennas in Cylindrically Layered Anisotropic Media With Multiple Horizontal Beds

Abstract

Abstract-Tilted-coil antennas (TCAs) have been proposed to increase the directional sensitivity and anisotropy sensitivity of well-logging tools used in oilfield exploration. In this paper, we simulate TCAs in 3-D cylindrically layered and anisotropic earth formations with multiple horizontal beds using an extended numerical mode-matching (NMM) approach. The field components are expanded in terms of longitudinal (vertical) eigenmodes to facilitate the analysis of transverse electric and transverse magnetic fields, which are coupled in this case. The perfectly matched layer is incorporated into the NMM formulation to mimic the Sommerfeld radiation condition in the longitudinal (vertical) direction. NMM results are compared with 3-D simulation results using finite-difference time-domain method and a pseudoanalytical approach based on Sommerfeld integrals (for problems where the latter is applicable), showing very good agreement.

Bayesian compressive sensing for ultrawideband inverse scattering in random media

“…It is a realization of a continuous random Gaussian medium with l cx = 125 m along the x-direction and l cy = 1.25 m along the ydirection. This is a good model for layered Earth formations encountered in geophysical exploration [60][61][62]. Prior knowledge of the layered nature of a problem can simplify the inversion significantly by solving the problem as a 1D inversion problem (i.e., restricting the unknowns to spatial harmonics along the y-direction), as shown in figure 10 x-direction as a surface controlled source electromagnetic (CSEM) array.…”

Indoor exclusion zone analysis in a nuclear power plant with wirelessHART application

“…Based on those results, we can obtain the modified EZ including the NPP indoor geometry, which is referred to as "indoor EZ." To accurately analyze the variations between the indoor EZ and free-space EZ, in-depth verifications are performed using the multiple reflection ray tracing, modal analysis [15,16,17,18,19,20] in the cylindrical coordinate, and measurements [21,22]. The results demonstrate that the proposed indoor EZ is more practical and suitable for the NPP environment than the EZ in free-space.…”