now don't get your ghutras in a knot

From Rigzone:

Total up what Saudi Oil Minister Ali Naimi and his aides say the kingdom has produced from February to April and you get 848 million barrels.
But OPEC estimates based on secondary sources put the total at 839 million barrels. And the International Energy Agency pegs it at 814 million barrels - a 34 million barrel difference.

Usually we see member states under-reporting production relative to quotas - they simply want to make some more cash when oil prices are high. So what's up with apparent over-reporting? Why is it important? 4%? Who cares?

...the number question cuts to the heart of Saudi credibility. It has, after all, staked its reputation on its ability meet world oil demand.
And what the Saudis say matters. When it comes to oil, Naimi is like Federal Reserve Chairman Alan Greenspan. He can rattle the oil drum as dramatically as Greenspan moves the dollar or stock markets.
In short, as the only country with any significant spare capacity and a quarter of the world's proven oil reserves, Saudi Arabia is essentially the central bank for oil.
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Under pressure from the U.S. and other economies smarting from $50-plus oil, the Saudis have pledged to spend $50 billion to ramp up output capacity over the next few years and promised to supply whatever the market wants.

Relative to many other parts of the world, Saudi production and delivery infrastructure has almost always been in poor shape. They have been investing huge amounts of cash to improve this over the last few years. I wager that what happened is one of the following...or maybe a combination:

1. Equipment problem in that what they *thought* they delivered what not what actually was delivered, so simple problem...oops, but where?
2. Equipment problem that affected delivery, but the Saudis are managing this credibility issue, so not such a bad problem, can be fixed.
3. Reservoir performance problem somewhere like Ghawar or Abqaiq. Saudi reservoir management is top-of-the-line, but it has not always been that way, and many are irreversibly damaged. Now THAT's a problem.