Loadings for Asia are expected to rise by 16.7 percent in June to around 2.43 million barrels per day, from May's 2.085 million bpd. This is the highest since January this year and up a full 22 percent from last June's sub-2 million bpd figure that marked a nine-month low.

China's daily intake will rise to 1.57 million bpd in June, from 1.17 million bpd in May, also the highest since January.

Reuters data shows that more Chinese refining capacity was offline in the month of May than at any time in the last few years, which in turn pushed refinery runs down from the previous month's record highs, but traders and analysts expect a firm bounce-back this month.

Part of the problem for West African grades has been the premium of Brent crude futures to both WTI futures and benchmark Dubai futures, which has rendered Atlantic Basin grades far less competitive against US crude.

Major buyer Unipec, the trading arm of Sinopec, offered June-loading cargoes of Cabinda, Kissanje, Saturno and Mondo, as well as Congolese Djeno on a delivered basis in Shandong, home to a number of large so-called Chinese teapot refineries.

Separately, Sinopec plans to boost its imports of US crude to record highs this month, after Unipec bought 16 million barrels, or about 533,000 bpd of US oil to load this month, the largest volume ever to be lifted in a month by the company and worth about $1.1 billion.

The Nigerian June loading programme took almost a month longer than usual to clear, because of the slowdown in demand.

Angolan grades however proved more successful in finding buyers and account in large part for the rise in exports to China.