After thinking about it, your reference is probably to a statement at the ASPO-USA conference by Peter Wells. He is not from IHS himself, but analyzed IHS data and came up with a peak date of 2020. His presentation can be found here. I didn't take all that good notes, so don't remember that comment specifically.

When I first read your comment, I thought you were referring to the paper by Aage Figenschou, with Matt Simmons, that is up on the APSO-USA web site now. It says:

Saudi Arabia is being assumed to produce 15.7 mbpd although they have never promised to do so. Sadad al Husseini, former head of E&P in Saudi Aramco, has said the Saudis should not produce more than 12 mbpd if they want to avoid damaging their reservoirs. He has also said that Middle East OPEC will never produce more than 25 mbpd. Yet IEA projects that these countries will produce 37.1 mbpd by 2030. There is clearly a downside risk of some magnitude.