once the nature of the trap is understood (amusingly enough that...

once the nature of the trap is understood (amusingly enough that usually happens after a dry hole) the field can be mapped with the same accuracy as any other field but while the 'edges' are uncertain you need to be careful.

A well known example is Chinguetti:

"http://www.offshore-technology.com/projects/Chinguetti/

Estimated recoverable oil reserves were originally put at 120m bbl (19m m³) but in November 2006 Woodside issued a statement cutting the field’s Proven and Probable (2P) reserves to 53m bbl. At the end of 2007, 2P reserves were put at 34m bbl. "

The reservoir turned out to be heavily stratigraphic and much more complex than earlier thought. It is frustrating to shareholders when new fields reserves are not announced but sometimes a solid number cannot yet be calculated.

As far as identifying strat plays it looks like VPE is using the 3D to directly map the channel with some success. This is a good sign of course but dont expect 100% success in the future. Anything over a 50% hit rate would give the JV a highly profitable program.