Dune Energy Inc.(fka DUNRQ)

[geopressure]

1] Drilling salt can be super-easy and fast, or it can extremely difficult. Because salt often under a lot of tectonic stress and it is plastic (flowable) in nature, it can shift, resulting in stuck-pipe and it has even been known to collapse casing (the drill-pipe and bit went through the casing, but after a drilling run, the bit was unable to come back out of the casing because it had been egg-shaped). Pore-Pressures can be unusually high or unusually low when exiting salt leading to kicks or lost-circulation, respectively. 'Rubble Zones' are often present at the base of salt structures and can be unstable as well.

In my limited experience, thin salt seams or welds cause the most problems related to shifting. Larger salt canopies or domes (in this case) are generally more stable. Repsol should be able to handle anything related to abnormal pore-pressures or rubble zones, it would just take an extra day or two.

2] This link should help give you an idea of how much oil is there:

http://files.shareholder.com/downloads/ABEA-2D0WMQ/0x0x379665/741a2e59-b24e-43ca-a6fa-5610d1502702/5_2010_06_ANALYST_PRESENTATION_WEBPOSTING_GULF_OF_MEXICO.pdf

Repsol is conservatively estimating 133 million barrels and they have a good reputation to back it up.
Offshore reservoirs like this are composed of unconsolidated sands. This results in the pore fluids actually sharing a part in supporting the weight of overlying formations. This results in the high production rates documented offshore. They are speculating, but they can look at the seismic image and estimate how much oil/gas the reservoir would hold.

3] The presentation above shows that Noble has had a 50/50 chance in sub-salt plays in Miocene Sands like this well. Repsol has developed & mastered the art of imaging seismic data below salt formations, and played a big part in the Huge finds offshore Brazil. Also, nothing makes a better seal than evaporites like salt or anhydrite. Repsol has the funds to drill anywhere in the world, but they chose this little platform just South of the Mississippi. They wouldn't be risking their reputation if they weren't confident that their seismic technology is correct and that it is oil, not water in those sands.