Eagle Ford Shale
Geography and Geology
Shale Outcrops
The name Eagle Ford comes from the small Texas town where the shale outcrops can be found in clay form on the earth’s surface. The Eagle Ford Shale is made up of sedimentary rock that contains oil and natural gas; it is the source rock for Austin Chalk, located 4,000 to 14,000 feet below the earth’s surface.
The Eagle Ford Shale extends approximately 50-miles wide, 400-miles long and has an average thickness of 250 feet. The shale is most commonly associated with the 14-county region that surrounds the play, including: Atascosa, Bee, DeWitt, Dimmit, Frio, Gonzales, Karnes, La Salle, Live Oak, Maverick, McMullen, Webb, Wilson, and Zavala. The Eagle Ford is also frequently correlated with six additional counties that are experiencing tremendous indirect and induced impact from the shale play, namely Bexar, Jim Wells, Nueces, San Patricio, Uvalde and Victoria Counties. Collectively, these counties are referred to as the surrounding “20-county region.”