I think it would be a mistake to discount most of these production numbers very much.  They are based on some fairly sophisticated analysis, and since most are in Deep water have required a fairly high level of validity to convince the oil companies to invest billions of dollars in their development.  Further although the Saudi oilfields are old, they were produced earlier probably using vertical well technology.  If they are now switching to maximum reservoir contact, with internal well valving to control the water cut then it is possible that they might get the production up to the level projected - I suspect that we will see from how Haradh performs, as it comes on stream,  and so far - without oil coming out of the ground - it is reported to be on schedule.