Premium
EM AND IP RESPONSE OF A STEEL WELL CASING FOR A FOUR‐ELECTRODE SURFACE ARRAY. PART I: THEORY *
Author(s) -
WAIT J. R.,
WILLIAMS J. T.
Publication year - 1985
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 - 10.1111/j.1365-2478.1985.tb00775.x
Subject(s) - casing , eddy current , conductor , polarization (electrochemistry) , homogeneous , electrical conductor , electrolyte , equivalent circuit , corrosion , mechanics , electrode , frequency response , geology , materials science , electrical engineering , physics , composite material , voltage , chemistry , geophysics , engineering , thermodynamics , quantum mechanics
A bstract The basic formulation for the mutual coupling between grounded circuits in the presence of a vertical conductor is used to examine the full electromagnetic and induced polarization response for a homogeneous half‐space model. Both interfacial polarization at the steel/electrolyte boundary and induced eddy currents in the casing are accounted for in the analysis. It is shown that for mild steel casings the eddy currents, hitherto neglected, play an important role because of their strong frequency dependence. Calculated curves of the appar‐ ent complex resistivity as a function of frequency show that the overall response can be influenced by the state of corrosion at the surface of the casing.