Patent ID: 6717411
Filing Date: 2004-04-06
Classification: G01V

Abstract:
A method of investigating subterranean strata which comprises:(a) deploying an electric dipole transmitter antenna; (b) deploying an electric dipole receiver antenna at a predetermined offset distance from the transmitter; (c) applying an electromagnetic (EM) field to the strata using the transmitter; (d) detecting the EM wave field response using the receiver; (e) extracting phase information from the wave response; (f) repeating the procedure with the transmitter and/or receiver in different locations for a plurality of transmissions; and (g) using the phase information from the wave response for the plurality of transmissions, in order to determine the presence and/or nature of the reservoir in which the transmission frequency is from 0.01 Hz to 1 kHz by analyzing the detected wave field for the presence of a refracted wave component.