By Nicole Friedman and Timothy Puko 

Oil prices eked out a gain Friday but settled lower for the week after the U.S. Federal Reserve chairwoman left the door open for a sooner-than-later rate increase.

U.S. crude for October delivery settled up 31 cents, or 0.7%, to $47.64 a barrel on the New York Mercantile Exchange. Prices fell 3% this week.

Brent, the global benchmark, rose 25 cents, or 0.5%, to $49.92 a barrel on ICE Futures Europe. Prices fell 1.9% on the week.

Oil prices have wavered this week as investors weighed continued concerns that the global market remains oversupplied against new indications that the Organization of the Petroleum Exporting Countries could agree to a production freeze in September.

U.S. commercial inventories of crude oil and refined products rose to a record high, a sign that the global glut of oil persists, federal data showed this week. But reports that Iran could join major producers in talks next month about coordinated action increased optimism among market participants.

"There's a lot of price uncertainty," said Robert Boslego, managing director of Boslego Risk Services in Santa Barbara, Calif. "Oil inventories keep reaching new highs," he said, adding that the big question whether OPEC members will intervene "if prices go back down to $40."

Chairwoman Janet Yellen, speaking at the annual central bankers' summit Friday at Jackson Hole, Wyo., signaled growing conviction that the central bank will raise short-term interest rates in the weeks or months ahead.

An increase in U.S. interest rates could lift the dollar, which would make oil more expensive for traders who conduct business in other currencies.

Also on Friday, weekly U.S. drilling data from oil-field services company Baker Hughes Inc. showed that the number of rigs drilling for oil in the U.S. was unchanged this week. The rig count had risen for eight straight weeks as the springtime rally in oil prices prompted some producers to invest in new production, sparking concerns among investors that the global oversupply of crude was set to persist and push prices lower. The lack of additional rigs this week could lessened those worries.

Bank of America Merrill Lynch said Friday it is holding its 2017 forecast for Brent at $61 a barrel, but noted that a rising dollar could keep oil prices lower than the bank expects. "Oil prices keep a strong correlation to the U.S. [dollar], and a hawkish Fed is a key risk to our outlook."

Gasoline futures settled up 0.14 cent, or 0.1%, at $1.5128 a gallon. Prices fell 0.01% this week.

Diesel futures fell 1.22 cents, or 0.8%, to $1.4972 a gallon, capping a 1.5% weekly loss.

Write to Nicole Friedman at nicole.friedman@wsj.com and Timothy Puko at tim.puko@wsj.com

(END) Dow Jones Newswires

August 26, 2016 16:49 ET (20:49 GMT)