International benchmark Brent crude traded at $61.84 per barrel at 11.57 GMT on Friday while the price of American benchmark West Texas Intermediate (WTI) was $52.87 per barrel at the same time.
Brent oil started the week at $57.84 per barrel at 06.45 GMT on Monday while WTI registered at $48.73 a barrel.
Crude oil prices started the new week with gains on positive expectations from the negotiations between the U.S. and China on Monday to resolve trade disputes.
Nonetheless on Monday, American investment banking and financial services firm Goldman Sachs lowered its oil price forecast for 2019 citing rising oil output, high inventory and low global demand.
The firm said in a note that it expects international benchmark Brent crude to average $62.50 per barrel this year, down from its prior estimate of $70 a barrel. WTI is forecast to average $55.50 a barrel in 2019, down from the previous expectation of $64.50 per barrel.
On Tuesday, crude oil prices were slightly down at the start of trading, despite reports that Saudi Arabia cut its crude exports to help boost prices. Brent oil traded at $57.28 per barrel at 0620 GMT for a daily loss of 0.5 percent while WTI was at $48.55 a barrel at the same time showing a 0.4 percent loss.
At the start of trading on Wednesday, crude oil prices were up around 1 percent through OPEC curbing oil production and with the ongoing trade talks between the U.S. and China generating investor optimism.
OPEC and its allies agreed on Dec. 7 to curb their total crude oil production by 1.2 million barrels per day from Jan. 1 for six months. The agreement aims to trim some of the supply glut in the global oil market and drive prices higher.
At trading start on Thursday, oil prices were down around 1 percent as U.S. crude production endured at a record high level to keep a downward pressure on prices.
Brent crude traded at $60.77 per barrel at 0745 GMT on Thursday with a 1.1 percent decline, after it ended Wednesday at $61.44 a barrel. WTI was recorded as $51.75 a barrel at the same time marking a 0.8 percent loss, after closing the previous session at $52.17 per barrel.
By Gulsen Cagatay