Crude prices rose on Friday for the second straight day following Fed Chair Yellen's speech, as demand rises on the commodity due to bullish forecasts for economic performance.
U.S. crude futures last traded at $47.64 a barrel, up from the opening price of $47.36, with an intraday high at $48.43, and a low at $46.92.
Yellen pointed to the improving path of growth for the economy, as it moves towards the bank's target, which restored confidence in the recovery of the U.S. economy and raised demand on risky assets like stocks and oil.
On the other hand, the dollar wavered up and down, which helped crude prices carry on yesterday's gains and get near a seven-week high.
The dollar index, which tracks the greenback against an array of six main currencies, last traded at 94.77, compared to the opening of 94.80, with a session-low at 94.57, and a high at 94.82, after the index hit its highest this week at 94.90.