Tillman said at an investment conference in New Orleans his company plans to deploy more than two dozen rigs in the Eagle Ford shale play in Texas, the Bakken reserve area in North Dakota and the Woodford shale area in Oklahoma.
"We continue to have high confidence in our ability to deliver on our North America long-term production growth targets," he said in a statement.
Last month, Tillman highlighted his company's production from U.S. shale. Combined, the three reserve areas gave up 144,000 barrels of oil per day on average during the fourth quarter.
In December, Marathon said it would invest more than 60 percent of its $5.9 billion in capital expenses next year on developing the Eagle Ford, Bakken and Woodford shale reserve areas in the United States.
The U.S. Energy Information Administration said in its monthly market forecast shale should help domestic oil production reach 8.4 million bpd this year, a 12 percent increase from the previous year.