According to recent data from consultancy DrillingInfo, half of all U.S. crude oil production comes from just 20 counties/development areas.

Included in the list are six Eagle Ford counties: Karnes, LaSalle, Dewitt, Dimmit, Gonzales and McMullen. Four counties in North Dakota covering another major shale play, the Bakken Shale, were also included.

The 20 counties/development areas covered make up only 2% of all oil producing counties across the country, but accounted for 52% of all oil production. Karnes County, which is the top oil producing county in the state, ranked at number seven on the list.

See below for a full list of Eagle Ford counties included in the DrillingInfo report and their respective ranking and daily production data:

• Karnes (7) - 214,000 b/d
• LaSalle (9) - 141,000 b/d
• Dewitt (13) - 133,000 b/d
• Dimmit (14) - 117,000 b/d
• Gonzales (15) - 116,000 b/d
• McMullen (19) - 88,000 b/d

In July of 2014, the Energy Information Administration (EIA) predicts the Eagle Ford Shale will produce 1.429 million b/d of crude oil and other liquids. That's approximately 24,000 b/d over June production, according to the EIA’s most recent Drilling Productivity Report. By 2020, some analysts predict the Eagle Ford will reach  two-million b/d of crude and condensate production.

Since the Eagle Ford oil boom began in 2009, more than 14,000 drilling permits have been issued by the Texas Railroad Commission (RRC) in the play. Permitting peaked in 2012 and 2013 in the top producing Eagle Ford counties, and has started to decline. According to the RRC, in 2013, there were 2,521 producing oil leases on schedule.