Exploration of lateral sequence-discontinuities using the vertical magnetic field generated by vertical electric dipole placed in borehole

摘要

Possibilities of detection of abrupt lateral conductivity changes are presented by mapping of the surface vertical magnetic field in the vicinity of the borehole. Magnetic field components generated by vertical electric bipole do not exist over a uniform or horizontally layered earth. Vertical magnetic field is caused exclusively by resistivity inhomogeneities. Therefore it is very sensitive to lateral discontinuities. A simplified inversion procedure - searching the anomalous subsurface horizontal current distribution linked with the discontinuity - is discussed and tested on synthetic examples.