Electrical and EM methods, 1980–2005

Abstract

The last two decades saw major advances in data collection, processing, and interpretation of electrical and EM data. Lower transmitter frequencies for airborne time-domain EM systems have made possible surveys in areas where conductive cover previously screened basement conductors. As with every other branch of technology, the evolving speed of the silicon chip and of streaming data to hard disk has revolutionized data collection and noise reduction processing. Major advances have been made on increasing the signal-to-noise ratios in ground EM data acquisition systems. Full-waveform recording and the use of multiple receivers are becoming common for ground EM techniques. Previously intractable 2D and 3D data inversions are now slowly becoming available. Finally, controlled-source EM techniques are now being used to detect and characterize hydrocarbon-bearing reservoirs in deepwater areas.