I just read the article. I figured it would be a very left wing article, but it wasn't. I'm liberal, but I tend to be conservative when it comes to financial and some environmental issues.
The farthest left theory in the article was that Saudi oil production has peaked and the fields producing now will have a production decline. I think this is a little far fetched but the rest of the article was enlightening.
They talked to the past head of the Saudi oil company in Saudi. This guy has a PhD from Brown and is one of the most prominent oil men of all time. He is most worried with the increase in demand. The world is currently consuming 84 million barrels a day and increasing by about 2 mil a year! Saudi has the largest known reserves at 263 bil barrels and produces 10.5 mil a day. At that rate it has about 68 years of oil! But they are planning to increase their production so maybe not so many years.
If oil production is increased too quickly out of a field, damage can occur which decreases the amount of possible production. According to the article this happened in Oman.
My take: yes there are untapped reserves in the World but I have a feeling oil is about to get real expensive. I just hope 20, 30, or 40 years from now we aren't all sitting around wondering why we were driving trucks and SUV's and looking like the biggest morons in history. As the cost of oil skyrockets, we'll see some pretty amazing new technologies, but I'll bet it's not hydrogen fuel cells.