Oil futures rose slightly on Friday as investors were encouraged by U.S. supply tightness.
Benchmark Brent for October delivery increased 6 cents to $51.09 per barrel on the day but looked set for a weekly loss of 2 percent.
September West Texas Intermediate crude rose 11 cents to $47.20 per barrel, although they were also on track to finish the week more than 3 percent lower.
The U.S. stockpiles have slumped 13 percent from their March top to below 2016 levels - 466.5 million barrels. At the same time, U.S. crude production leaped 13 percent to 9.5 million a day last week, its highest level since July 2015.