Effects of uncertainties in the position and orientation of both the transmitter and receivers on marine controlled-source electromagnetic data

Abstract

Simulation and interpretation of marine controlled-source electromagnetic (CSEM) data often approximate the transmitter source as an ideal horizontal electric dipole (HED) and assume that the receivers are located on a flat seabed. Actually, however, the transmitter dipole source will be rotated, tilted and deviated from the survey profile due to ocean currents. And free-fall receivers may be also rotated to some arbitrary horizontal orientation and located on sloping seafloor. In this paper, we investigate the effects of uncertainties in the transmitter tilt, transmitter rotation and transmitter deviation from the survey profile as well as in the receiver’s location and orientation on marine CSEM data. The model study shows that the uncertainties of all position and orientation parameters of both the transmitter and receivers can propagate into observed data uncertainties, but to a different extent. In interpreting marine data, field data uncertainties caused by the position and orientation uncertainties of both the transmitter and receivers need to be taken into account.