Oil prices were boosted amid supply outages in Nigeria and wildfires in Canada, two major exporters.
In Nigeria, an activist group protesting environmental pollution and oppression attacked pipelines, sending output to a 22-year low, according to Barclays analysts Miswin Mahesh, Michael Cohen and Warren Russell. Meanwhile, the housing for oil field workers was fields "effectively decimated" by a blaze in Alberta, Dennis Gartman told CNBC last week.
"In our view, these unplanned outages have helped cushion some of the effect of Iran's speedy recovery of exports," the Barclay's analysts wrote in a research note. "What was expected to be a source of supply over the tail end of this year is now already factored in, and political developments in Nigeria need to be assessed more carefully now to gauge the pace of return of these supplies and their effect on market balances."
Shares of Marathon are down more than 53 percent over the past year as historically-low oil prices have pressured shares. Apache has seen shares fall more than 13 percent in the past 12 months, while Murphy has fallen 32 percent and Transocean has fallen 54 percent in that time.
— CNBC's Gina Francolla contributed to this report.