Oil prices have fallen due to companies increasing output and filled inventories.
Brent crude oil slipped 50 cents at $42.97 a barrel, while US light crude fell 20 cents at $41.72, Reuters reported.
Data released by the US Government highlighted an increase in crude and gasoline stocks, which added to an already huge refined product glut worldwide.
PVM Oil Associates lead oil analyst Tamas Varga told the news agency: "US commercial stocks are a good reflection of the oversupplied nature of the global oil market."
Oil markets have fallen by as much as 70% between 2014 and early this year, having since recovered.
But oil prices remain low and weak refining margins are hitting energy companies.
Royal Dutch Shell posted a 70% fall in quarterly profit, which is well below estimates of analysts.
During the second quarter of this year, the company’s net income stood at $1bn, compared with expectations of $2.2bn and $3.8bn that was achieved during the same period last year.
Sun Global Investments CEO Mihir Kapadia said that oil was still being depressed by oversupply worries.