How much is global oil market oversupplied?

Global petroleum supply has exceeded demand since early this year, contrast to the shortage in the last year. Sluggish growth of demand while ample supply caused the situation. But how much is global petroleum market oversupplied at moment?

World balance of petroleum supply and demand was matched in 2009, but it turned to the shortage of supply due to the global economic recovery in 2010. Then, Libyan civil war suddenly stopped 1.6 million barrels per day of crude oil supply last year and led the global oil market to the significant shortage.

Urgent hike of output by producing countries made up for the shortage, and Libyan production has recovered quite faster than expected. Therefore, the decreasing crude oil supply from Iran by more than 1 million bpd due to the international sanction did not cause another shortage of supply in the global market.

The following table shows global balance of petroleum supply and demand based on data supplied by the U.S. Energy Information Administration, the Organization of Petroleum Exporting Countries and the International Energy Agency.

Except for EIA's estimate for 3Q 2012, that shows supply shortage due to steady demand, estimates and forecasts for 2012 and Q1 2013 are oversupply.
Meanwhile, EIA forecasts another round of oversupply in Q4 2012 and Q1 2013.

OPEC and IEA do not supply forecasts for OPEC member nations crude oil output yet. Relatively large minus figures in the balance cells in the table indicate necessary amount of OPEC crude oil supply in those periods.
Since recent crude oil output by OPEC is about 31 million bpd, that is much higher than the necessary volume, the supply shortage is unlikely to be seen until OPEC members decide to cut production significantly from the current level.

In the latest monthly report, OPEC has estimated October production by its 12 member countries at 30.95 million bpd and saw the world petroleum supply at 90.22 million bpd. IEA also estimated OPEC October crude oil output at 31.16 million bpd and assessed the world oil supply at 90.92 million bpd. Those numbers are all exceeding the demand forecasts for Q4.

On the other hand, Reuters earlier reported the survey result that OPEC crude oil output in November fell by 90,000 bpd from the previous month, and Bloomberg estimated the OPEC production declined by 330,000 bpd from a month ago.
Even if OPEC production decreases by 200,000 to 300,000 bpd from the October level, global balance of oil supply and demand estimated by OPEC or IEA still stays in oversupply.

It's true that recent volume of petroleum oversupply is shrinking compared to the first half of this year. The fact slightly confuses us. Why current crude oil prices are lower than the first half of this year? The market may have discounted the future slump of demand....