Premium
Analysis of a guided wave along a conducting structure in a borehole[Note 1. Received August 1996, revision accepted December 1997. ...]
Author(s) -
Ebihara S.,
Sato M.,
Niitsuma H.
Publication year - 1998
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1046/j.1365-2478.1998.00103.x
Subject(s) - borehole , geology , radar , antenna (radio) , azimuth , acoustics , well logging , signal (programming language) , geophysics , seismology , optics , physics , geotechnical engineering , telecommunications , engineering , programming language , computer science
A guided wave along a borehole is often observed in borehole radar measurements. These guided waves deform the antenna pattern and can cause artefacts in radar measurements. A water‐filled borehole or a conducting logging cable can function as a waveguide for electromagnetic waves under some conditions. We describe the theoretical characteristics of such a guided wave in a borehole and compare them with our experiments. The measured signal discussed was obtained with a directional borehole radar. This radar uses a cylindrical conformal array antenna as receiver and is a model of a conducting structure in a borehole. The induced field around the borehole was compared with the theory. The most fundamental symmetrical and asymmetrical modes were TM 01 and HE 11 , and they were identified in the measured signals using time–frequency distribution analysis and by observation of the azimuthal field distribution of the magnetic field.