seagull, page-28

INFO

Not quite right. COS was 21% for Trident (and close to that for the other 2 prospects) before 3D. After 3D and the seismic inversion studies (that assess reservoir porosity) GALP upgraded COS to 29%.

I did a bit of a search on COS and found a good presentation on the American Association f Petroleum Geologists website that included this example for a fictitious prospect called Alpha that can be seen here:

http://archives.aapg.org/slide_resources/schroeder/14/images/Slide34.jpg

In this example they consider 9 variables and get a COS of 61% because 3 of the 9 variables have a risk factor of 0.85 or 0.90 and the other 6 are 1.0 (no risk).

Its probably fair to say that with Trident being 29% there are a number of factors that are low risk and a couple that are moderate (say 0.6 or less) like trap and seal about which they know very little at this location whereas hydrocarbon presence and porosity they are more confident about.

The drill will tell!

H