I think the rough picture is that we are fairly clueless what is really going on with OPEC.  I don't completely agree with JD's math, because it's likely Ghawar's production was partially shut-in during parts of the eighties and nineties.  But nor do I have tremendous confidence in the Hubbert linearizations for those countries because the linear regimes are small and the production was far from unconstrained during a lot of the linear regime.  The linearization may be roughly indicative, but it's very hard to stand on it with cast-iron confidence.  When you do stability analyses on them, the answer you get is very sensitive to your choice of beginning and end years.

I think the production numbers have to be more solid than the reserve numbers because the missing barrels number (oil that can't be accounted for when you subtract the known consumption from the known production and take into account known stock changes) is not usually more than a couple of percent of global production - ie comparable to the discrepancies between the different production series (EIA, IEA, etc.  So whatever lies are being told about production numbers, they can't sum to more than a percent or two of the total.

So I think the only facts about OPEC that I have a lot of confidence is that for the last 12 months or so:

• rig counts are rising
  
• production is not increasing