Eagle Ford Shale

Eagle Ford Group Stratigraphic range: Cenomanian to Turonian 96 to 90 million years
Type	Group
Sub-units	Britton Formation, Arcadia Park Shale Formation, Lake Waco Formation, South Bosque Formation, Boquillas Formation
Underlies	Austin Chalk
Overlies	Woodbine Formation or Buda Limestone
Lithology
Primary	Shale
Other	Marl, limestone, sandstone, volcanic ash beds
Location
Region	Texas
Country	United States
Type section
Named for	Eagle Ford, Texas
Named by	Robert T. Hill

The Eagle Ford Group (also called the Eagle Ford Shale) is a sedimentary rock formation deposited during the Cenomanian and Turonian ages of the Late Cretaceous over much of the modern-day state of Texas. The Eagle Ford is predominantly composed of organic matter-rich fossiliferous marine shales and marls with interbedded thin limestones. It derives its name from outcrops on the banks of the West Fork of the Trinity River near the old community of Eagle Ford, which is now a neighborhood within the city of Dallas. The Eagle Ford outcrop belt trends from the Oklahoma/Texas border southward to San Antonio, westward to the Rio Grande, Big Bend National Park, and the Quitman Mountains of West Texas. It also occurs in the subsurface of East Texas and South Texas, where it is the source rock for oil found in the Woodbine, Austin Chalk, and the Buda Limestone, and is produced unconventionally in South Texas and the "Eaglebine" play of East Texas. The Eagle Ford was one of the most actively drilled targets for unconventional oil and gas in the United States in 2010, but its output had dropped sharply by 2015. By the summer of 2016, Eagle Ford spending had dropped by two thirds from $30 million in 2014 to $10 million, according to an analysis from the research firm, Wood Mackenzie. This strike has been the hardest hit of any oil fields in the world. The spending is, however, expected to increase to $11.6 million in 2017. A full recovery is not expected any time soon.

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