WTI or Brent ?

Brent Poised to Depose WTI as Most-Traded Oil Futures

"Daily trading in Brent jumped 14 percent to average 567,000 contracts in the year to Nov. 20 compared with all of 2011, while WTI fell 17 percent to 575,000, according to data from the ICE Futures Europe exchange in London and New York Mercantile Exchange compiled by Bloomberg. The number of Brent futures changing hands has exceeded those for WTI every month from April through October, the longest streak since at least 1995"

But not so fast.  From the same story.

"By some measures, WTI remains ahead. Open interest, the number of contracts that have not been closed, remains 30 percent higher for the U.S. futures at 1.5 million lots this year, compared with 1.16 million for Brent, data from the exchanges show...If the WTI volumes that are also registered on ICE’s exchange are added to those on Nymex, the U.S. grade remains the more widely-traded. Combined WTI volumes on ICE and Nymex have averaged 704,152 lots this year. "

What would be more interesting to know is what volume of physical oil cargoes are priced based on each of the two benchmarks.  I would suspect that Brent is well out ahead. Although if the IEA is correct (see here) in that the US is on its way to becoming the world's largest oil producer again then I would suspect that WTI will take over the lead role in physical pricing as well.