Patent ID: 7383132

Claim:
A method for displaying electromagnetic survey data to reveal resistive bodies in a subterranean region, said data obtained using an electromagnetic source moved to a plurality of positions along a survey line above the subterranean region with a plurality of electromagnetic receivers fixed along or near the survey line, said method comprising: (a) selecting a parameter related to electric or magnetic fields measured by the receivers, said parameter being selected to be dependent upon resistivity of subsurface layers penetrated by the electric and magnetic fields, and obtaining that parameter from the measured electromagnetic data for a plurality of source and receiver locations; (b) selecting a reference signal, said reference signal being representative of values of the selected electromagnetic parameter that would be generated by said electromagnetic source at the plurality of source and receiver locations absent targeted resistive bodies; (c) scaling the selected measured parameter using the reference signal; (d) plotting the scaled parameter values displayed by a color scale on a section graph with abscissa defining position along the survey line and ordinate defining depth in said subterranean region; and (e) identifying any anomalies in the color display of said plot, anomalies being areas in which the measured parameter differs from the reference signal.