SAR seepage slick detection carries an inherent uncertainty and therefore its true exploration potential is not met until slicks are sampled and validated.
Correlation can easily be made to the locations of seep-related features expressed on multibeam swath bathymetry, high resolution (or shallow) seismic, or conventional seismic, as this will show whether the seepage slicks overlie plausible migration pathways. These will then link the seep to either potential source kitchens, or more significantly to leaking traps.
It is likely that genuine seepage slicks will coincide with direct hydrocarbon indicators (phase reversals, flat spots, amplitude anomalies and gas blanking for example) on the seismic record. Surface seepage is also likely to overlie the location of seepage vents and bubble plumes. In many basins around the world, Fugro already have such data for this initial validation phase.
However, even more value is obtained if the slicks can be sampled at sea and geochemical data obtained. There are a number of ways of achieving this, and in each case Fugro provides the necessary expertise and equipment. Standard workflow for validation follows some or all of these steps:
- Airborne surveys - slick spotting using low-flying light aircraft (Fugro Airborne)
- Ship borne seep sampling surveys (Fugro Survey)
- Slick sampling and geochemical analysis (Fugro GeoLab Nor)
- Multi-beam swath bathymetry surveys (Fugro Survey)
- Acquisition of drop cores and geochemical data (Fugro Surface Geochemistry Acquisition, Fugro Geolab Nor)
- Integration of results with seismic (Fugro Robertsons, Fugro MCS)