Eagle Ford
Shale

The Eagle Ford Shale is a south Texas oil play that produces from a wide range of fluid types depending on depth and location. It is one of the more geographically distinct US shale plays, with a clear progression from oil-rich shallow areas in the north to gas-rich deep areas in the south, with a transitional condensate zone in between. The Eagle Ford emerged as a major US oil source in the early 2010s and continues to produce at high volumes despite being less prominent in headlines than the Permian.

Therocks beneath your minerals.

The Eagle Ford is a Late Cretaceous calcareous shale deposited roughly 95 million years ago in a shallow marine setting along the Western Interior Seaway. The formation thickens to the south, ranging from 50 to 250 feet across the productive trend, and dips toward the Gulf of Mexico, deepening from a few thousand feet of depth in the north to more than 14,000 feet at the southern edge of the productive window.

This depth gradient produces three distinct production windows:

The black oil window covers the northern part of the trend (counties like Wilson, Atascosa, Frio, La Salle, McMullen, and Live Oak). Wells produce primarily oil with minor associated gas. Depths range from 4,000 to 8,000 feet.

The volatile oil and condensate window covers the central trend (counties like Karnes, DeWitt, Gonzales, and parts of Dimmit and Webb). Wells produce a mix of oil, condensate, and gas, with high gas-to-oil ratios but meaningful liquid revenue per barrel of oil equivalent. Depths range from 8,000 to 12,000 feet.

The dry gas window covers the southern trend (counties like Webb, Maverick, southern Dimmit, and the southern fringes of Live Oak and McMullen). Wells produce mostly dry gas. Depths range from 10,000 to 14,000 feet.

The Eagle Ford is divided informally into Lower Eagle Ford and Upper Eagle Ford, with the Lower Eagle Ford generally being the more productive horizontal target across most of the trend.

Where theproduction lives.

Eagle Ford activity is concentrated in the volatile oil and condensate window where economics are most favorable. Karnes, DeWitt, Gonzales, La Salle, and McMullen counties see the most consistent drilling. EOG, ConocoPhillips (through the 2024 Marathon Oil acquisition), Chesapeake (now Expand Energy), Sundance, and Murphy are among the major operators.

Modern Eagle Ford wells use completion designs adapted to the local reservoir properties (oil-window completions differ meaningfully from condensate-window completions). Initial production rates vary widely by location, with the strongest results in the most productive parts of Karnes and DeWitt counties.

The Eagle Ford has settled into a steady-state development pattern, with operators drilling capital-disciplined programs focused on infill development of held acreage rather than aggressive expansion. The play has not seen the production growth surges of the Permian over the past five years, but it has produced steady, reliable contributions to US oil supply.

Mineral rights in theEagle Ford.

The Eagle Ford drives most royalty checks across the south Texas play. Where your tract sits within the play determines what you receive. Owners in the northern oil window (Karnes, Gonzales, and surrounding counties) primarily receive oil-driven royalty income. Owners in the central volatile window receive a mix. Owners in the southern dry gas window receive primarily gas-driven royalty income.

For inheritors with Eagle Ford interests, the play’s mature horizontal development means most actively-leased acreage has seen at least one round of drilling. The most-developed counties (Karnes, DeWitt, La Salle) often have multiple wells per drilling spacing unit, generating staged royalty income across years.

ConocoPhillips’s 2024 acquisition of Marathon Oil affected many Eagle Ford royalty owners. Marathon was a significant Eagle Ford operator, and the transition transferred operator of record on a meaningful number of wells. If your records still show Marathon, the underlying interest carried over to ConocoPhillips unchanged. We are happy to help you trace the current operator if the legacy name on your paperwork is making the chain hard to follow.