Error propagation with synthetic aperture for CSEM

Controlled-source electromagnetics (CSEM) is a geophysical method used to find resistive reservoirs in the conductive subsurface in marine settings. We previously demonstrated how the application of synthetic aperture, virtually increasing the length and width of the CSEM source by combining the responses from multiple individual sources, improves the detectability of targets with CSEM. In this paper, we focus on reducing the propagation of noise with the application of weighted synthetic aperture. We first detail an optimization method that calculates the weights that are designed to reduce noise and maximize the presence of the reservoir. We demonstrate the benefits of this method with a synthetic CSEM example where the towlines are several kilometers away from the receivers. The application of a weighted synthetic aperture array designed to reduce noise and increase the anomaly allows the signal from the reservoir to be extracted from the noisy responses and possibly allows for the use of CSEM in new areas where the towlines cannot be directly positioned over the receivers.