USING LOW FREQUENCY FOR DETECTING FORMATION STRUCTURES FILLED WITH MAGNETIC FLUID

摘要

A method for mapping a subterranean formation having an electrically conductive wellbore casing therein may include using a low frequency electromagnetic (EM) transmitter and EM receiver operating at a low frequency of less than or equal to 10 Hertz to perform a first EM survey of the subterranean formation, and with either the low frequency EM transmitter or EM receiver within the electrically conductive well-bore casing. The method may further include injecting a magnetic fluid into the subterranean formation, and using the low frequency EM transmitter and EM receiver to perform a second EM survey of the subterranean formation after injecting the magnetic fluid.