The evidence seems to support the Saudis claim that they still have a lot of oil left (URR > 200Gb). However, if Ghawar (which constitutes almost 40% of their production) goes into depletion it won't be easy to increase production.
khebab...you seem to have a very good grasp on what's going on...would you elucidate what evidence you possess that the saudis have a URR > 200Gb?
Well, this is common sense, Saudi Arabia production comes from a few giant fields that have been online since the 50s, if one collapses... see Simmons's last book.

The result of the Hubbert linearization done by Stuart (URR @ 200Gb) seems to be consistent with the current production levels.