Analysts said oil likely garnered extra selling pressure from Thursday's rout in U.S. equities.
While the U.S. oil contract plummeted, Thursday's declines were modest in Brent, which is more leveraged to the international oil market.
Key questions include the effect of new sanctions on Russian oil production and the impact of continued violence in Libya on the North African country's output.
Eurasia Group predicted Brent would continue to trade in the $105-to-$110-a-barrel range in the third quarter.
"Concerns about geopolitical risk will continue to be supportive, particularly in relation to the perceived fragility of the partial recovery in Libyan production and a renewal of concerns about risks related to Iran," the consultancy said in a note.
Copyright Agence France-Presse, 2014