Brent crude futures were down 52 cents, or 0.7%, at $72.56 a barrel.
US West Texas Intermediate (WTI) crude futures were down 39 cents, or 0.6%, at $70.65 a barrel, after retreating 1.5% on Thursday and is also set to be flat on the week.
Brent crude futures were down 30 cents, or 0.4%, at $68.16 a barrel by 1004 GMT, having jumped 3% on Monday. US West Texas Intermediate futures were off 42 cents, or 0.6%, at $65.63 a barrel, after gaining 3.9% the previous session.
Still, the global recovery from the COVID-19 pandemic is patchy, indicating a mixed outlook for oil demand.