Near Surface Structures and Anisotropy from Cross-correlations of Ambient Seismic Noise at the Valhall Oil Field

We have used 6 hours of continuous vertical component geophone data from the Valhall Life of Field Seismic (LoFS) network to perform an Ambient Noise Surface Wave Tomography of the first hundreds meters of the Valhall field overburden to determine surface wave velocity. We were able to retrieve high-resolution features like paleo-channels that were previously highlighted by full waveform inversion of active source seismic data. Furthermore, by computing the 2 690 040 cross-correlation functions between the full set of sensor pairs combinations, we were able to quantify the spatial distribution of azimuthal anisotropy over the whole network and link it to previous results from active seismic experiments.