$100 per barrel is the threshold that Dubai crude oil is now approaching, carried there by a surge in purchasing from Asian buyers.
Dubai crude is the primary pricing mechanism for Middle Eastern crude flowing to Asian refiners. When buying from that bloc surges, the benchmark price follows directly. The current surge has pressed prices close enough to $100 that the level has moved from a distant reference to the near-term test.
Asia's buyers carry enough collective weight in the Dubai crude market to shift the benchmark on their own. That capacity is what the current surge reflects, with $100 per barrel now the defining level for the move.