Transient marine electromagnetics in shallow water: A sensitivity and resolution study of the vertical electric field at short ranges

Abstract

ABSTRACT We analyzed the sensitivity of transient step-off responses of shallow-water marine controlled-source electromagnetic configurations, specifically, horizontal electric dipole sources and vertical electric dipole receivers in the near field of the time domain (HED-Ez(t)). The capabilities of this configuration were compared with commonly used configurations, specifically, horizontal electric dipole sources and horizontal electric dipole receivers in the frequency domain (HED-Ex(f)). By examining some simplified models of local hydrocarbon reservoirs representing separate resistive bodies of limited size buried at different depths in the conductive sediments, and an example of a complex 3D geologic structure, the applications of HED-Ez(t) and HED-Ex(f) configurations and their limitations in terms of depth, size, and transverse resistance were evaluated.