Located in South Texas, the Eagle Ford Shale was discovered by Petrohawk Energy Corp in 2008. The company came to the region hoping to find natural gas-rich shale similar to its holdings in the Haynesville Shale formation on the border of Texas, Oklahoma, and Arkansas. Although the Eagle Ford Shale holds substantial amounts of natural gas, the discovery of oil and natural gas liquids (NGL) is what really inspired a staking rush in the Eagle Ford.

The Eagle Ford consists of three distinct regions, as shown in the Eagle Ford map below:

Map of Eagle Ford Regions; Source: US Energy Information Administration

The northern part of the shale play (highlighted in green) is known as the oil window, and in addition to producing crude oil, it also contains lesser amounts of natural gas and NGLs. Situated to the south of the oil window, the wet-gas region (highlighted in red) produces gas along with high volumes of NGLs. The southernmost region (highlighted in orange) contains mostly dry natural gas. Because oil and natural gas liquids command a higher price than natural gas, producers have mostly focused on extracting the formation’s oil and NGL resources.

The Eagle Ford Shale is not a typical shale formation, and is more closely related to marl—a type of lime-rich mudstone that contains variable amounts of clays and silt. As such, the Eagle Ford Shale is very brittle and is therefore easily fractured using hydraulic fracturing techniques. The Eagle Ford formation is also more porous and permeable than many other shales, which makes the extraction of hydrocarbons much less difficult.

The Eagle Ford Shale formation is relatively close to the surface, with productive depths located between 4,000 feet and 6,000 feet. By contrast, the Bakken Shale’s most productive layer is found at depths of 10,000 feet.

Map of Dallas/Ft. Worth Section Showing the Eagle Ford Shale Source: Wikipedia

Petrohawk Energy Corp’s success in the Eagle Ford soon spurred a massive staking rush. EOG Resources (NYSE: EOG) was one of the first companies to see the Eagle Ford’s potential, and the firm shrewdly amassed large swaths of land at prices around $500 per acre. Less than a year after initiating its staking campaign, EOG Resources announced that its 500,000-acre land holdings contain estimated potential reserves of 900 million barrels of oil equivalent. More recently, the firm nearly doubled that earlier estimate and now believes its Eagle Ford holdings could yield up to 1.6 billion barrels of oil equivalent.

As the map below shows, oil and gas producers dominate land holdings in the Eagle Ford Formation.

Map of Eagle Ford Shale Land Claims; Source: Rystad Energy

To learn more about investing in the Eagle Ford Shale and other US energy plays, be sure to get our free investment report, The Complete Investor’s Guide to Striking It Big in Today’s Hottest Shale Plays.