Leanan -

Note that in the text they are speaking of "contracting" rigs. They aren't building more drilling rigs, but rather offering higher rates to obtain the rigs from elsewhere on the globe. This "bidding up" escalates throughout the industry, increasing rig rental rates and raising exploration costs. It also delays drilling programs in other areas by creating a temporary rig shortage as contractors accept the more lucrative Saudi bids.

That tells me that the Saudis have VERY profitable drilling prospects.  If they can afford to pay more than anyone else for the rigs, it can only be because they are certain that their remainging costs will be lower than everybody elses - the oil they are going after is going to be very cheap to extract and deliver.

And that implies that they have quite a bit of it still in the ground, relative to the rest of the world.

Why are they exploring in deep water when they supposedly have a half trillion barrels of proven reserves in their existing fields?