SINGAPORE, Feb 21 (Reuters) – Crude oil benchmarks in the Middle East, Oman and Dubai, surged to new all-time highs on Monday on tight supplies, while jitters over Russian energy supply disruption amid the Ukraine crisis left global oil markets in severe backwardation held.

Brent’s premium over Dubai rose to $6.31 a barrel on Monday, nearing a 2013 high of $6.48 recorded last week and keeping arbitrage windows closed on Asia.

Iraqi SOMO has sold 2 million barrels of Basra Medium Crude for…