Oil prices climbed for a seventh straight session in thin trading on Friday, posting their longest bull run since April, but still turned in their worst first-half performance since 1998.
Lingering worries about oversupply have knocked 16 percent off Brent crude so far this year, despite a deal involving OPEC members and some other major producers to curb production.
On Friday, oilfield services firm Baker Hughes reported its weekly count of oil rigs operating in U.S. fields fell for the first time since January. It was down by two oil rigs to a total of 756.
U.S. crude futures ended Friday's session $1.11 higher, up 2.5 percent, at $46.04 a barrel, having added 7 percent this week. Benchmark Brent climbed 48 cents to $47.90 a barrel by 2:38 p.m. ET (1838 GMT) and has gained 5 percent this week.
Trading volume was low ahead of the U.S. Independence Day holiday weekend.