Investing.com - West Texas Intermediate and Brent oil future turned lower in choppy trade on Thursday, as investors continued to focus on a glut in global supplies.
On the New York Mercantile Exchange, crude oil for delivery in February dipped 4 cents, or 0.08%, to trade at $48.61 a barrel during U.S. morning hours, after hitting a daily peak of $49.64.
A day earlier, WTI oil fell to $46.83, the weakest level since April 2009, before turning higher to end at $48.65, up 72 cents, or 1.5%, after data showed that oil supplies in the U.S. fell unexpectedly last week.
Elsewhere, on the ICE Futures Exchange in London, Brent oil for February delivery hit a session high of $51.90 a barrel, before turning lower to trade at $50.99, down 17 cents, or 0.32%.
On Wednesday, London-traded Brent prices tumbled to $49.66, a level not seen since May 2009, before recovering to settle at $51.15, up 5 cents, or 0.1%.
The US dollar index, which measures the greenback against a basket of six major currencies, climbed to a 12-year high, boosted by the diverging policy outlook between the Federal Reserve and central banks in Europe and Japan.
Oil prices typically weaken when the U.S. currency strengthens as the dollar-priced commodity becomes more expensive for holders of other currencies.
London-traded Brent prices lost nearly 48% in 2014, while WTI futures dropped almost 46% after the Organization of Petroleum Exporting Countries decided to maintain its output target at 30 million barrels a day.
The decision disappointed hopes the oil cartel would lower production to support the market, as a surplus develops amid the shale boom in the U.S., which is pumping at the fastest pace in more than 30 years.