Two stacked Texas plays in the same column — what's the difference, and what does it mean if your lease covers both?
Get a Free Mineral ValuationThe Austin Chalk and the Eagle Ford Shale are stacked above one another across central and south Texas. The Eagle Ford sits directly below the Austin Chalk; in most counties of overlap, the two zones are separated by 100-300 ft. Many Giddings-trend leases — and most south Texas leases — cover both depths.
For mineral owners whose lease covers both, your interest may receive royalty income from Austin Chalk wells, Eagle Ford wells, or both — depending on what each operator chooses to drill.
Austin Chalk: Upper Cretaceous fractured chalk; production driven by natural fractures supplied by chalk matrix; depths 7,000-12,000 ft TVD across the Giddings trend
Eagle Ford Shale: Upper Cretaceous calcareous shale; production driven by induced fractures from hydraulic stimulation of low-permeability matrix; depths typically 9,000-13,000 ft TVD in central Texas; deeper to the south
Both plays produce oil, condensate, and natural gas — but the mix varies by depth and geography:
Austin Chalk: predominantly oil and condensate in the Giddings trend; gassier in the south
Eagle Ford: three-window play — oil window in the north (Karnes / DeWitt), condensate window in the middle (Live Oak / McMullen), dry-gas window in the south (Webb / Dimmit / La Salle)
Austin Chalk: commercial production since 1960; commercial horizontal since the early 1990s; modern long-lateral era began approximately 2018
Eagle Ford: commercial production began 2008-2009 with Petrohawk's Hawkville field discovery; the play is purely a 21st-century unconventional phenomenon
Austin Chalk: mix of modern long-lateral redevelopers (EOG, Magnolia, Crownquest) and a long tail of legacy short-lateral horizontal and vertical operators going back to the 1960s
Eagle Ford: dominated by large public independents (EOG, ConocoPhillips, Chesapeake, Devon, Marathon, Magnolia, BP) with limited private/stripper operator presence
Many Giddings-trend and south Texas mineral interests are subject to leases that cover BOTH Austin Chalk and Eagle Ford depths. For a current valuation, both zones must be considered:
Currently producing zone — what's actually generating royalty checks today
Other-zone optionality — the value of future drilling in the unproduced zone
Lease terms specific to each zone — some leases have different royalty rates or different held-by-production rules per depth
A valuation that only credits the currently-producing zone undervalues the interest. Request a written valuation that explicitly accounts for both Austin Chalk and Eagle Ford economics.
Buckhead Energy buys mineral rights across both Austin Chalk and Eagle Ford depths.
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