Oil prices rose nearly 1 percent on Thursday on expectations the dollar would weaken after Friday's key speech by U.S. Federal Reserve Chair Janet Yellen, making greenback-denominated commodities more attractive to holders of other currencies.
Crude futures also rebounded from a selloff in the previous session on support from players buying on dips and looking for a bottom on speculation that next month's informal meeting between the Organization of the Petroleum Exporting Countries and other major producers could result in output curbs.
Some traders cited bullish data issued by energy monitoring firm Genscape showed a drawdown of more than 313,000 barrels at the Cushing, Oklahoma delivery point for U.S. crude futures during the week to Aug. 23.
Brent crude futures rose 66 cents to $49.71 a barrel, after settling down 1.8 percent on Wednesday.
U.S. crude's West Texas Intermediate (WTI) futures rose 56 cents, or 1.2 percent, to $47.33. WTI lost nearly 3 percent in the previous session.
"There are two things going - wariness about the dollar tumbling after Friday's Fed event and bottom-fishing by players looking for more speculative support for the market ahead of a possible OPEC deal next month," a broker said.
The dollar eased against a basket of currencies as some investors sold the currency before the annual global central bankers' gathering in Jackson Hole, Wyoming, where Yellen was to speak on U.S. monetary policy on Friday.
Recent U.S. economic data has pointed to sluggish productivity and subdued inflation, suggesting the Fed could hold off on raising interest rates. The U.S. central bank hiked rates for the first time in nearly a decade in December.
Members of OPEC will meet on the sidelines of the International Energy Forum, which groups producers and consumers, in Algeria on Sept. 26-28.
There is speculation that OPEC and other producers led by Russia will agree to output curbs at the meeting. Few analysts expect such a deal, pointing to record OPEC production and a tendency by the group's key members, such as Saudi Arabia and Iran, to protect their market share at the expense of prices.
"We do not expect a production freeze - let alone a production cut - from the OPEC meeting," investment bank Jefferies said in a report.