- Copyright © 2003 Society of Exploration Geophysicists
Potential hydrocarbon-bearing sediment structures in the Faroe-Shetland Basin are often overlain by basaltic sequences of stacked flows up to several kilometers thick. With conventional seismic acquisition and processing methods, it is difficult to image the internal (intrabasalt) and underlying (subbasalt) structures. Scattering from the highly reflective top of the basalt and short-period multiples from intrabasalt boundaries may completely mask reflections from the base of the basalt and below. High attenuation of seismic energy in the basaltic sequence due to its complex internal structure generally causes a weak subbasalt signal. Long-period multiples, such as those generated between the sea bottom and the top-basalt boundary, may obscure subbasalt reflections and energy reflected from the basement.
Recent investigations have shown that integrated near-offset and wide-angle acquisition (e.g., Fruehn et al., 2001) combined with a broadband, low-frequency source (Ziolkowski et al., 2003) have the potential to overcome some of the aforementioned difficulties. Application of model-based processing (e.g., Hanssen et al., 2003) and inversion techniques (Fruehn et al., 1998) are useful for identifying weak subbasalt features and to support data interpretation. Processing of converted-wave energy (e.g., Barzaghi et al., 2002) may also enhance our ability to extract additional information about subbasalt structures contained in seismic reflection data.
Figure 1 shows the location of the study area between the Faroe and the Shetland Islands, which is of particular interest for the hydrocarbon industry. A key factor in assessing the hydrocarbon potential in this area is the exploration of traps in Mesozoic and lowermost Cenozoic subbasalt sediments, including anticlines and domes in the Faroe-Shetland Basin and tilted fault blocks from Mesozoic rifting. This region has been investigated with the Faroe Large Aperture Research Experiment (FLARE). An overview of the acquisition and processing strategy of the FLARE-project is presented by White et al. (1999). The FLARE-experiment comprises 12 …