Seismic efficiency on a vast scale – a case study from offshore Gabon

Seismic surveys come in all shapes and sizes, depending on factors such as objectives, geographical area, geological environment, local licence requirements, and budget. Small surveys over a focused area can make sense individually, though there may be inefficiencies, such as many vessel turns when recording short lines. When several such surveys are located near by there can be both gaps in coverage and redundancy of the aperture needed to ensure that areas of interest are fully imaged. Moreover, velocity models may seem fine-tuned for each individual survey but frequently do not connect together smoothly when examined on a regional scale. At some point, it makes more sense to acquire and process one large survey rather than several smaller pieces. Multi-client surveys provide a cost-effective route to large, high-quality datasets. Costs are shared, so larger surveys can be acquired, for a better overall view of the prospectivity than is generally the case with smaller, proprietary surveys. Access to large surveys, in both mature and frontier areas, allows companies to reduce their exploration risk. It can also help to cut the time between the award of a licence and the drilling of the first well.