Subsurface conductivity mapping using controlled source electromagnetic method

Controlled Source Electromagnetic (CSEM) approach to map subsurface conductivity is one of the techniques included in the 2010 revision of IEEE Standard 356 which deals with the measurements of electromagnetic properties of earth media. The CSEM method typically involves an electric dipole transmitter, operating at around 0.1–10 Hz frequency, and a set of receivers appropriately placed in the survey zone. The received signals are then processed to generate conductivity profile of the zone of interest. This paper presents an overview of CSEM measurement techniques and describes some of the challenges in data acquisition and processing. An example from marine CSEM for subsurface conductivity mapping is presented to illustrate the method.