We present processing methods and results from a passive low-frequency (LF) seismic campaign over a giant producing oil field in Abu Dhabi. Processing methods include ambient wave field analysis and the mitigation of the influence of anthropogenic infrastructure noise. Without careful processing to remove these components of the ambient wave field, data are strictly measures of human activity. However, spatially and temporally consistent energy anomalies on the vertical component cluster within the center of the survey area. Available current reservoir data show some correlation with the energy attributes calculated with two different methods.@en

We applied seismic interferometry to data from an oceanbottom survey offshore Norway and found that ambient seismic noise can be used to constrain subsurface attenuation on a reservoir scale. By crosscorrelating only a few days of recordings by broadband ocean bottom seismometers, we were able to retrieve empirical Green’s functions associated with surface waves in the frequency range between 0.2 and 0.6 Hz and acoustic waves traveling through the sea water between 1.0 and 2.5 Hz. We discovered that the decay of these surface waves cannot be explained by geometrical spreading alone and required an additional loss of energy with distance. We quantified this observed attenuation in the frequency domain using a modified Bessel function to describe the cross-spectrum in a stationary field. We averaged cross-spectra of equally spaced station couples and sorted these azimuthally averaged cross-spectra with distance. We then obtained frequency-dependent estimates of attenuation by minimizing the misfit of the real parts to a damped Bessel function. The resulting quality factors as function of frequency are indicative of the depth variation of attenuation and correlated with the geology in the survey area.@en