Frequency-domain marine controlled-source electromagnetic inversion using rotational invariants

In marine controlled-source electromagnetic (CSEM) inversion, electromagnetic (EM)-field components, for example, the inline electric field components, are frequently utilized. For dependable data processing and inversion, precise orientations of the sources and receivers are essential, including their heading, tilt, and roll. Nevertheless, there could be potential uncertainties in the inversion and interpretation process. This is particularly true when the orientation information is lost during field data collection, for example, when the compass and tilt recordings are not obtainable. This research proposes a novel marine CSEM inversion algorithm. Instead of relying on EM fields, the orientation-independent rotational invariants are used. This approach allows for the inversion without having to take into account the orientations of the sources or receivers. The application of rotational invariants in the frequency-domain inversion of marine CSEM data is described. Numerical tests are conducted for both 1-D and 2-D scenarios using both the rotational invariants.