The Brent crude January futures contract lost 46 cents, or 0.61 percent, to trade at $74.58 per barrel by GMT0451. West Texas Intermediate (WTI) crude futures fell 41 cents to $64.90 a barrel.
Both benchmarks posted their worst monthly performance since July 2016 on Wednesday, with Brent falling 8.8 percent for October and WTI dropping 10.9 percent.
Thursday’s drops came after U.S. Energy Information Administration data showed crude oil inventories climbed for a sixth straight week.
“The strong built in oil inventories is likely to keep downward pressure on oil prices,” Research analysts said in a note.
Still, Goldman Sachs (NYSE:GS) on Thursday reiterated a year-end forecast for Brent prices of $80 barrel. The bank said 2018 oil demand growth, though down slightly, remains above consensus expectations, and said Chinese demand continues to show resilience despite concerns over the world’s second-biggest economy.