Oil prices fell nearly 3 percent on Friday after data showed U.S. production and rig counts rose last week just as OPEC exports hit a 2017 high, casting doubt over efforts by producers to curb global oversupply.
U.S. West Texas Intermediate (WTI) crude futures ended Friday's session down $1.29, or 2.8 percent, to $44.23 per barrel.
Brent crude futures, the international benchmark for oil prices, were trading down $1.47, or 3.1 percent, at $46.64 per barrel by 2:36 p.m. ET (1836 GMT).
After rising earlier in the week, U.S. crude ended the week down nearly 4 percent, a sixth weekly decline in the past seven.
"The stream of relentless supply continues," said Matt Smith, director of commodity research at Clipperdata.