Marathon issued its second quarter report showing an adjusted net income of $603 million, up from the $478 million reported for second quarter 2013.
Apart from Libya, where production is down because of lingering violence, Marathon said its production was up more than 5 percent for the quarter for an average 383,000 barrels of oil equivalent per day and most of that growth was driven by shale basins in North Dakota, Oklahoma and Texas.
"Continued strong production growth and crude oil and condensate price realizations across our U.S. resource plays helped Marathon Oil deliver another solid financial quarter," President and Chief Executive Officer Lee Tillman said in a statement Monday.
British energy company BP said in the June publication of its annual energy review shale production in the United States accounted for nearly all of the gains from outside the Organization of Petroleum Exporting Countries. Oil production increases in the United States last year were among the most "the world has ever seen," the report said.
Tillman said the Eagle Ford shale play in Texas should generate double-digit production growth for the rest of the year, while the Bakken reserve area in North Dakota and similar resource basins in Oklahoma should follow that general trend.