Deep-water subsurface imagingusing OBS interferometry

Seismic interferometry processing is applied to an active seismic survey collected on ocean bottom seismometers (OBS) deployed at 900-m water depth over a carbonate/ hydrates mound in the Gulf of Mexico. Common midpoint processing and stacking of the extracted Green’s function gives the subsurface PP reflectivity, with a horizontal resolution of half the receiver spacing. The obtained seismic section is comparable to classical upgoing/downgoing wavefield decomposition and deconvolution applied on a common receiver gather. Seismic interferometry does not require precise knowledge of source geometry or shooting times, but more accurate results are obtained when including this information for segmenting the signals before the crosscorrelations, especially when signals from distant surveys are present in the data. Reflectivity estimates can be obtained with the crosscorrelation of pressure or vertical particle velocity signals, but the pressure data gives the best resolution due to the wider frequency bandwidth and the reduced amount of noise bursts.