Unrest that closed major Libyan ports cut the chaotic OPEC nation's crude production in July, but output rebounded by 280,000 barrels per day (bpd) in August to 950,000 bpd, and ports reopened, according to the International Energy Agency, which coordinates the energy policies of industrialized nations.

Four tankers carrying a total of 2.1 million barrels, or 70,800 barrels per day (bpd), from Libya's major port in Es Sider and other terminals will arrive or have already made port in Philadelphia, New York and Houston this month.

The Seascout arrived on Sept. 4 with 600,000 barrels at Phillips 66's Bayway Refinery in the Port of New York and New Jersey, the data showed. Phillips 66 declined to comment.

The Silverway, chartered by Italian oil major Eni, is set to reach Philadelphia on Wednesday after leaving Libya's Mellitah port with more than 600,000 barrels.

In August, US East Coast refiners including Monroe Energy in Trainer, Pennsylvania, shifted to light, sweet Saharan Blend from Algeria to offset the drop in imports from Libya, Thomson Reuters data show.

The US imported 140,000 barrels per day of the Saharan blend in August, the largest volume in two years. Imports of Saharan blend are set to fall to 48,000 bpd in September, the data show.

Other African suppliers are able to quickly step in and replace Libyan barrels that are lost due to unrest, said Judith Dwarkin, chief economist at market intelligence firm RS Energy Group.

Saharan Blend traded around a $0.70 and $1 discount to global benchmark Brent in August for September delivery and rose to a $0.20 premium in September, traders said.