Broadband

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In seismic exploration broadband refers to a wider band of frequencies being recorded than in conventional seismic exploration.

In the marine case the conventional acquisition system is said to give a usable bandwidth of typically between 8–80 Hz, whereas broadband seismic systems are claimed to give usable frequencies from as low as 2.5 Hz up to 200 Hz or more for shallow targets. On land, modern vibrators today can produce signal frequencies down to 1.5 Hz.

Low frequency data provides deeper penetration useful for imaging deep targets, and provides greater stability in inversion. Broader bandwidths produce sharper detailed definition. Both low and high frequencies are required for high-resolution imaging of important shallow features such as thin beds and small sedimentary traps.

Introduction

Broadband marine seismic data is evolving as the new standard in petroleum geoscience, recent interest in broadband seismic, and especially the low frequencies end, has triggered several seismic acquisition solutions. Increasing the bandwidth of the seismic signal in the low end of the frequency spectrum improves penetration and resolution in reflection seismic data, and it is beneficial in waveform and impedance inversion.

Broadband is also a term used in marine seismic recording where the streamer is at different depths below the water surface to change the position of the receiver ghost notch in the frequency spectrum so that the low frequency range is complete when the traces from the different receivers at different depths are combined in processing. For more detailed information visit the CGG website that describes their proprietary implementation called BroadSeis.