Seep Screening Methodology
Oil Seep detection is an ideal technique for evaluating large frontier offshore basins and also for targeting seismic surveys in both pre and post licensing phases.
Almost all known oil provinces in the world seep. In the first half of this century, seeps led to the discovery of some of the world's largest oil fields such as Kirkuk (Iraq), Majid-i-Sulaiman (Iran) and Burgan (Kuwait), plus many giant oil fields around Baku (Azerbaijan).
In offshore basins, oil seeps leaking from reservoirs can reach the sea surface, usually in the form of oil coated gas bubbles, and then form slicks identifiable from satellite. This is due to the dampening effect of the oil on the capillary wavelets, which produces an area of relative calm compared to the background waves. A summary oil seep diagram can be found here.
Band 5 of Landsat can be used to detect this effect, but the radar satellites (ERS and RADARSAT) provide cloud-free imagery with near global coverage.
Infoterra has a unique, cost-effective Offshore Seep Screening Service, featuring:
- Fast access to a substantial ERS data archive
- Rapid acquisition of RADARSAT data globally
- Careful weather screening to select only scenes acquired in the optimal weather window
- A minimum of two scenes per location are used in order to help distinguish natural seepage from pollution
- Only higher resolution SAR data is used (ERS pri and Radarsat Standard Scenes) so no smaller seeps are missed
- A team practised in slick interpretation
- Classification of slicks into probabilities of natural oil seeps, pollution and natural film
- Assignment of confidence levels by analysis of slick morphology, backscatter reduction and edge characteristics
