EOG Resources, which has headquarters in Houston, said it increased its net potential recoverable reserve estimate from Eagle Ford by 45 percent to 3.2 billion barrels of oil equivalent.
Chief Executive Officer Bill Thomas was quoted by the online energy news site Upstream as saying the reserve area was the "single largest source" of his company's oil production growth last year.
"Through virtually flawless execution of our operations plan, we generated robust crude oil production growth," he said Tuesday.
The Eagle Ford shale area is spread out over southern Texas. The Texas Railroad Commission, the state's energy regulator, said in December the average production rate from January through October 2013 was 659,092 barrels per day. Production from 2011 to 2012 more than doubled.
"To put our Eagle Ford position in simple terms, our current reserve potential is almost four times what we estimated four years ago when EOG discovered the play," Thomas said.