Benchmark oil for October delivery gained US$1.39, or 1.4 per cent, to close at US$106.42 a barrel on the New York Mercantile Exchange.
Oil rose US$1.18 a barrel Thursday. Even with the two days of gains, oil fell US$1.04 a barrel last week.
Brent crude, which sets prices for imported oil used by many US refineries, gained US$1.14 on Friday to US$111.04 a barrel on the ICE Futures exchange in London.
In other energy futures trading on Nymex Friday, heating oil added three cents to US$3.10 per gallon; natural gas fell six cents to US$3.49 per 1,000 cubic feet; and wholesale gasolene gained three cents to US$2.87 per gallon.