Much like a poker player that lets you look at his/her cards and you realize that they have nothing. It seems the Saudi's have done just that. The Financial Times has a page one article claiming this. Here is the money quote:
But private warnings also point to a worsening long-term outllook, with Saudi
officials saying that the Organisation of the Petroleum Exporting Countries will
be unable to meet projected western demand in 10 to 15 years.