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Calculation of apparent conductivity for the transient electromagnetic (coincident loop) method using an HP-67 calculator

1980; Society of Exploration Geophysicists; Volume: 45; Issue: 7 Linguagem: Inglês

10.1190/1.1441117

1942-2156

Brian R. Spies, Art Raiche,

Geophysical Methods and Applications

The interpretation of coincident‐loop transient electromagnetic (TEM) surveys is often aided by the transformation of TEM data to apparent conductivity values. Present methods of calculating apparent conductivity have a limited usefulness or require access to a computer. This paper presents an algorithm for calculating apparent conductivity to an accuracy of better than 1 percent for values of the parameter x = σμA/4πt up to 10, where σ = conductivity, μ = magnetic permeability, A = loop area, and t = sample time. This range of x is sufficient for most situations encountered in field work. The algorithm has been programmed for an HP-67 pocket calculator, and the program steps and user instructions are given in standard format. Execution time ranges from 6 to 15 sec. The program should assist the interpretation of TEM surveys in the field.