The Opec oil cartel, led by Saudi Arabia, will pocket a record of more than $1tn in net oil revenues in 2012 as the annual average price for Brent, the benchmark, heads to an all-time high in spite of weak economic growth.

The windfall will provide fresh capital to some of the world’s largest sovereign wealth funds. United Arab Emirates, Saudi Arabia and Kuwait, the most influential members of the cartel, have three of the world’s 10 largest SWFs by assets under management, according to estimates by the SWF Institute.

With one trading day left before the end of the year, Brent oil prices are on the point of seeing an average for the year of about $111.50 a barrel, higher than the previous high set in 2011 of $110.90. The benchmark closed at or above $100 every trading day in 2012, bar 24 days in June and early July.