Texas · Eagle Ford · Black Oil Window

Sell Mineral Rights
in Karnes County,
Texas.

Karnes County sits at the heart of the Eagle Ford black oil window, where the play first proved itself at scale in 2010 and 2011. If you own mineral rights here, you own a piece of one of the most productive shale oil counties in the country, with active Eagle Ford development, legacy production still on the books, and a growing pipeline of Austin Chalk redevelopment. We are happy to help you understand what you have.

Core
Eagle Ford
Black oil window
~10,000ft
Eagle Ford Depth
typical TVD
7,500ft
Standard Lateral
with longer designs
Two
Stacked Targets
Eagle Ford, Austin Chalk
2010
Horizontal Era
Long history of activity
01 The Basin

The heart of the Eagle Ford
black oil window.

Karnes County sits in South Texas, roughly an hour southeast of San Antonio, in the part of the Eagle Ford that produces predominantly black oil. The Eagle Ford itself runs in a long arc across South Texas, transitioning from oil in the north to condensate to dry gas as it deepens to the south. Karnes lies in the sweet spot of that transition where the rock is mature enough to have generated oil, but not so deep that it has been cooked into gas.

The Eagle Ford was the first major US shale oil play to be developed at scale, and Karnes was at the center of it from the beginning. The first horizontal Eagle Ford wells in Karnes were drilled around 2009 and 2010, and the county quickly became one of the most active in Texas. Operators built out gathering pipelines, processing facilities, and trucking infrastructure that still serves the region today. Production peaked in the mid 2010s, declined as drilling slowed during the 2015 to 2016 oil price downturn, and has settled into a steadier rhythm with periodic refracturing and Austin Chalk development layered on top of the original Eagle Ford program.

Karnes is the closest thing the Eagle Ford has to a core. The wells came in early, came in strong, and many of them are still producing more than a decade later.

If you are reading this, you may own a piece of that. Maybe you inherited minerals tracing back to a Spanish or Mexican land grant, an old family ranch, or a homestead patent. Maybe you have been receiving royalty checks since 2011 and are wondering where things go from here. Maybe a landman just sent you a letter about a new Austin Chalk lease. This page walks through the rock, the operators, the geography, valuation, and the regulatory landscape, in plain language.

Starting point

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02 The Rock

Two productive horizons
stacked together.

Karnes County's productive geology is straightforward by Permian standards but exceptionally consistent. The Eagle Ford shale is the primary target, lying at roughly 9,000 to 11,000 feet across most of the county. The Austin Chalk sits directly above it and has emerged as a meaningful secondary target. Both are typically developed horizontally, with the Eagle Ford program now mature and Austin Chalk activity accelerating.

Eagle FordPrimary horizontal target

The Eagle Ford shale is an organic-rich marine mudstone deposited during the Late Cretaceous. Across Karnes County the formation is generally between 200 and 400 feet thick, with operators typically targeting the lower Eagle Ford bench, which has the highest organic content and the best fracability. Karnes sits in the part of the play where the Eagle Ford is mature enough to produce predominantly black oil rather than condensate or gas.

For mineral owners, Eagle Ford development in Karnes typically means one or more long-lateral horizontal wells per spacing unit, with steep initial decline followed by a long, shallow tail. Many original Eagle Ford wells drilled in 2011 and 2012 are still producing, and operators are increasingly returning to refrac existing wells with modern completion techniques.

Depth Range
9,000 to 11,000 ft
Type
Organic-rich marine mudstone
Window
Black oil
Typical Lateral
7,500 ft, longer designs growing
Austin ChalkStacked above the Eagle Ford

The Austin Chalk lies directly above the Eagle Ford and is a fractured carbonate rather than a true shale. It has produced oil in Karnes and surrounding counties since long before the Eagle Ford boom, originally through vertical and short horizontal wells. In recent years operators have re-focused on the Austin Chalk as a horizontal target, drilling long laterals using modern completion techniques developed in the Eagle Ford.

For mineral owners, Austin Chalk activity is increasingly meaningful in Karnes. A spacing unit with established Eagle Ford production may now see additional Austin Chalk wells drilled, generating new royalty streams on the same minerals. The Austin Chalk and Eagle Ford are typically considered separate formations for spacing and royalty purposes.

Depth Range
8,500 to 10,500 ft
Type
Fractured carbonate
Status
Active redevelopment
History
Pre-Eagle Ford production
Buda & Other HorizonsLegacy and selective targets

Below the Eagle Ford, the Buda limestone has produced from vertical wells in parts of Karnes County for decades. Other shallower zones, including various Wilcox and Olmos sands, have also produced historically. None of these are major modern horizontal targets, but legacy vertical production from these zones still continues across many parts of the county and contributes to royalty income for some mineral owners.

The practical implication for mineral owners is that even outside of new Eagle Ford and Austin Chalk activity, older vertical wells may still be on production and generating modest royalty checks. These should not be ignored when looking at the full picture of what your minerals produce.

Buda Depth
~11,500 ft
Olmos / Wilcox
Shallower vertical
Status
Legacy vertical, selective
Where Active
Variable across county
03 The Operators

Who is drilling on your
Karnes County minerals.

The Eagle Ford operator landscape has consolidated over the years as the original wave of independents was acquired or merged with larger players. The operators below are leaders in current Karnes County activity, but Karnes has many more meaningful operators than this list captures.

i.
Marathon Oil (now ConocoPhillips)
Marathon Oil built one of the largest Eagle Ford positions through the early 2010s, with substantial leasehold in and around Karnes County. ConocoPhillips closed its acquisition of Marathon in late 2024, bringing the position under the ConocoPhillips umbrella. The combined company is among the most active operators in the Karnes core, with continued Eagle Ford and Austin Chalk drilling activity.
Major · Combined position
Top in Karnes
ii.
ConocoPhillips
ConocoPhillips already held meaningful Eagle Ford acreage prior to the Marathon transaction, much of it acquired through the 2017 Burlington Resources legacy and subsequent additions. The company is among the largest oil producers in Karnes County and a consistent driller of new Eagle Ford and Austin Chalk inventory.
Major · Long-tenured
Top Producer
iii.
EOG Resources
EOG was one of the earliest movers in the Eagle Ford and helped define the modern horizontal program in Karnes and surrounding counties. EOG continues to hold meaningful acreage in the Eagle Ford and is among the most technically respected operators in the basin, with consistent drilling and completion innovation.
Public · Eagle Ford pioneer
Top 5 in Karnes
iv.
Devon Energy
Devon Energy holds meaningful Eagle Ford acreage including positions in Karnes County, with the position bolstered through the 2022 acquisition of Validus Energy and additional Eagle Ford bolt-ons. Devon has been an active driller of both Eagle Ford and Austin Chalk wells in the area.
Major · Active driller
Top 5 in Karnes
v.
Crescent Energy
Crescent Energy holds substantial Eagle Ford acreage assembled through a series of transactions, including the 2024 acquisition of SilverBow Resources. Crescent's position spans both oil and gas windows of the Eagle Ford and includes meaningful Karnes County exposure.
Public · Recent consolidator
Active in Karnes
vi.
Long Tail of Public and Private Operators
Karnes County has many additional meaningful operators including Magnolia Oil and Gas, BPX Energy (BP), Murphy Oil, Sundance Energy, and various private operators that have acquired packages from public sellers over the years. Mineral owners may see different operator names on different wells within the same general area depending on which operator drilled which spacing unit and which assets have changed hands.
Mixed · Many active
Many Active Operators
See a familiar name?

We know how these operators develop in Karnes County. Happy to give you context on yours.

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04 The Geography

Not all Karnes County
minerals are built the same.

Karnes County covers about 750 square miles across South Texas. The Eagle Ford runs through the county at productive depth and quality, but reservoir character, operator activity, and remaining inventory vary by area. Karnes City is the county seat, and Kenedy is the largest town. Where in the county your minerals sit shapes everything from operator activity to formation depth and well vintage.

Karnes City Core
Central Karnes
The geographic and operational center of the county. The Karnes City area was among the earliest parts of the Eagle Ford to be developed at scale, and many spacing units here have multi-vintage well counts. Remaining inventory is meaningful given Austin Chalk redevelopment and refrac potential on older Eagle Ford wells.
Activity: Highest Development: Mature, infill
Kenedy / Hwy 181 Corridor
Southwest Karnes
The Kenedy area along the US 181 corridor sits in the heart of the Eagle Ford black oil window. Activity here has been consistently high, with established gathering and processing infrastructure supporting continued development. Several of the highest-IP wells in the county have been drilled in this part of the county.
Activity: High Development: Active
Northern Karnes / Wilson Border
Northern Karnes
Northern Karnes transitions toward Wilson County and the shallower, more oil-rich edge of the Eagle Ford. Eagle Ford depth thins here and operators have selectively developed across the county boundary. The Austin Chalk has been a particular focus in northern Karnes in recent years.
Activity: Moderate to High Development: Mixed Eagle Ford and Chalk
Southern Karnes / Live Oak Border
Southern Karnes
Southern Karnes sits closer to the transition between black oil and condensate windows of the Eagle Ford. Wells here may produce a higher gas-to-oil ratio than the central core, which affects how royalty value distributes between oil and gas. Operators have developed this area consistently over the years.
Activity: High Development: Active
Eastern Karnes / DeWitt Border
Eastern Karnes
Eastern Karnes runs toward DeWitt County and the volatile oil and condensate transition zone of the Eagle Ford. Activity remains meaningful here, with operators drilling Eagle Ford and Austin Chalk laterals across the county boundary. Spacing units near the DeWitt line often see continuous development on both sides.
Activity: High Development: Active
Western Karnes / Atascosa Border
Western Karnes
Western Karnes transitions toward Atascosa County and the shallower oil edge of the Eagle Ford. Activity is generally consistent but well productivity can vary as the formation thins. Mineral interests here are valued more on a combination of legacy production and selective new drilling than on continuous infill.
Activity: Moderate Development: Selective
05 Your Valuation

What your Karnes County
mineral rights are worth.

Valuation in Karnes County reflects its position as the heart of the Eagle Ford black oil window. Long history of activity, established infrastructure, multiple stacked targets, and continued refrac and Austin Chalk development all support strong mineral valuations. The four scenarios below cover what we see most often.

01
Producing Minerals with Active Royalty Income
Valued on cash flow plus remaining inventory
If your Karnes County minerals are actively producing, valuation typically starts with the trailing twelve months of royalty income. A buyer applies a multiple based on expected remaining well life, future drilling potential across Eagle Ford and Austin Chalk, refrac potential on older wells, and commodity outlook. Karnes multiples tend to be among the higher tiers in the Eagle Ford because of the depth of remaining inventory and the established infrastructure.
What shapes the number: well vintage and remaining life across multiple existing wells, how many additional Eagle Ford and Austin Chalk locations remain undrilled, your royalty rate, the operator quality, and your lease cost-deduction language.
02
Unleased Minerals in Active Development
Valued on drilling proximity and future potential
Unleased Karnes County minerals, particularly in the Karnes City core or Kenedy corridor, are valued aggressively on expected development timing. Operators continue to compete for acreage in active areas, which supports negotiation on lease bonus and royalty rate. Unleased minerals also carry optionality for both Eagle Ford and Austin Chalk development.
What shapes the number: nearby permit activity, the operator's recent drilling pace in your area, formation quality beneath your specific tract, comparable lease bonuses paid on surrounding tracts, and whether the area is part of an operator's near-term drilling plan.
03
Small Fractional Interests & Inherited Positions
Often worth substantially more than expected
Many Karnes County mineral owners hold small fractional interests inherited across multiple generations, often tracing back to original Spanish and Mexican land grants or later homestead patents. The chains of title can be long and complex, but Karnes's productive geology and active operators mean even small fractional interests can carry meaningful value. We pay these interests the same attention as larger ones and are comfortable doing the title research.
What shapes the number: net mineral acre count, royalty rate if leased, producing status, accumulated unpaid suspense (sometimes meaningful for inherited interests), and whether other heirs holding the same chain are also active.
04
Older Wells with Refrac and Austin Chalk Potential
Valued on legacy income plus new development
Many Karnes mineral owners have been receiving royalty checks since 2011 or 2012 from original Eagle Ford wells that are now well into their decline curves. The valuation question for these interests is often whether new development, either refracs of existing Eagle Ford wells or new Austin Chalk laterals, is likely to add new royalty streams. In active operator footprints in Karnes, the answer is often yes, which materially affects value.
What shapes the number: current decline-curve income, operator's recent activity in offset spacing units, whether Austin Chalk has been drilled nearby, refrac activity in the area, and the lease's depth severance and Pugh clause language.
Your specific situation

We would rather look at real facts than speak in generalities. Send us what you have.

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06 The Regulatory Landscape

Texas rules,
Eagle Ford realities.

Karnes County operates under the Texas oil and gas regime, administered primarily by the Texas Railroad Commission. The on-the-ground realities reflect the long history of Eagle Ford development, established gathering and processing infrastructure, and the layered chain-of-title work that comes with old South Texas land grants and decades of legacy production.

The Texas RRC and how spacing works

The Texas Railroad Commission (RRC) regulates oil and gas activity on private and state minerals in Texas. The RRC permits wells, conducts hearings on spacing and unitization issues, and maintains the public well database. Texas Eagle Ford spacing has evolved over the years as operators moved to longer laterals, and modern Karnes wells are often pooled into larger units that match two-mile or longer laterals across multiple legacy tracts.

Texas pooling and lease language

Texas relies primarily on lease pooling clauses rather than mandatory pooling. Whether and how your minerals can be pooled into a horizontal unit depends substantially on the language of your specific lease. Older leases sometimes have restrictive pooling language that can complicate modern unit formation. Newer leases generally have broader pooling clauses written with horizontal development in mind. This is one of the most important pieces of lease language to review when looking at value.

Post-production costs and royalty deductions

Texas generally allows operators to deduct certain post-production costs from royalty calculations unless the lease specifies otherwise. Whether your specific lease permits which deductions, and how the operator calculates them, depends entirely on the lease language. The Texas Supreme Court has issued several major decisions over the years interpreting royalty clauses, and the practical effect on a given owner can be material. Reading your lease carefully and checking how the operator is calculating deductions is worth doing.

Surface use and South Texas land grants

Many Karnes County tracts trace back to original Spanish and Mexican land grants, with chains of title that can span many generations of heirs spread across multiple states and sometimes multiple countries. This is normal in South Texas and is not in itself an obstacle to a clean transaction, but it does mean title work in Karnes is sometimes more involved than in counties with newer settlement histories. We are comfortable working through these chains.

07 Questions We Hear Often

The real questions
mineral owners ask.

We have been through these conversations hundreds of times. Below are honest answers to the things people actually want to know.

01
How much are mineral rights worth in Karnes County, Texas?
Karnes County sits in the heart of the Eagle Ford black oil window, which generally supports some of the strongest mineral valuations in the play. That said, values vary widely depending on where in the county you own, whether your minerals are leased or producing, the operator, your royalty rate, and lease cost-deduction language. The only way to know what your specific minerals are worth is to look at the actual facts. We are happy to do that for you, at no cost and with no obligation to sell.
02
Why is Karnes County considered the core of the Eagle Ford?
Karnes sits at the geological sweet spot where the Eagle Ford has the right thickness, organic content, and pressure to produce predominantly black oil rather than condensate or dry gas. The county was among the first to see large-scale horizontal development starting in 2010, and many of the highest-IP wells in the Eagle Ford have been drilled here. Karnes also benefits from established gathering, processing, and takeaway infrastructure built out during the early Eagle Ford boom.
03
I inherited mineral rights in Karnes County but I do not have any documents. What do I do?
You are not alone. This is a common situation. Start by gathering anything you do have: old letters from operators, tax statements, probate records, royalty stubs, division orders. The Karnes County Clerk's office in Karnes City keeps deed records, and the Texas Railroad Commission maintains a public database of wells, operators, and production. We can usually identify what someone owns with just a name and a rough idea of where the minerals are located, because Texas mineral records are publicly accessible.
04
Should I sell my Karnes County mineral rights now or hold them?
That depends on your situation. People who hold typically want long-term royalty income, do not need cash for other priorities, and are comfortable with commodity price volatility and the steep decline curves typical of Eagle Ford wells. People who sell typically want to convert future uncertain income into certain present value, simplify their estate, or use the capital for something else. Karnes has a long history of production with refrac and Austin Chalk redevelopment activity continuing, but the Eagle Ford decline curve also supports strong sale valuations. Neither is wrong. We can help you think through the tradeoffs without pressure to pick a side.
05
My Karnes County wells were drilled years ago. Are they still worth anything?
Often yes, sometimes meaningfully so. The Eagle Ford was first developed at scale in Karnes starting around 2010 to 2012, and many of those original wells are still producing on long, shallow declines. More importantly, operators in Karnes are now actively refracturing older wells and drilling Austin Chalk laterals above existing Eagle Ford development. So even minerals under older Eagle Ford production may have meaningful new activity ahead.
06
What is the Austin Chalk and why does it matter for Karnes minerals?
The Austin Chalk sits stratigraphically above the Eagle Ford and has its own oil productivity in parts of South Texas. For years it was treated as a secondary target in Karnes, but operators have re-focused on horizontal Austin Chalk development as Eagle Ford inventory matures. For mineral owners this matters because a spacing unit with established Eagle Ford production may now also see Austin Chalk wells drilled, generating a new set of royalty payments on the same minerals.
07
My royalty statements have post-production cost deductions. Is that normal?
It depends on your lease. Texas generally allows operators to deduct certain post-production costs from royalty calculations unless the lease specifies otherwise. Whether your specific lease permits which deductions, and how the operator calculates them, depends entirely on the lease language. Reading your lease carefully and checking how the operator is calculating deductions is worth doing. We can help review your statements and lease language together if helpful.
08
Can I sell mineral rights I inherited if other family members inherited the same minerals?
Yes, you can sell your undivided fractional interest without needing the other heirs to participate. This is extremely common in Karnes County, where many interests have been subdivided across generations of heirs going back to original Spanish and Mexican land grants and later homestead patents. A good buyer will work with your specific interest, not require you to round up cousins. We do this all the time.
09
How does the sale process actually work?
Step one, we do the research. You send us what you have, we pull Texas Railroad Commission records, we check operator activity in the spacing unit, and we build an analysis. Step two, we send you a written summary with our reasoning. Step three, if you want to proceed, we handle the mineral deed preparation, you sign at a notary, and funds are wired at close. We move on your timeline, whether that is quick or deliberate. There is no charge for the research and no obligation to sell.
10
Why should I sell to Timberline Minerals specifically?
We are a family-owned office with roots in Texas and Montana. We work across the primary US basins and we know the Eagle Ford in detail, including Karnes-specific dynamics like Austin Chalk redevelopment, refracs of legacy wells, and the chain-of-title complexity that comes with old South Texas grants. We work with mineral interests of all sizes including small fractional positions. Our process is straightforward: we research the tract, share what we find, and make an offer. The decision to sell is yours, and we are happy to help you understand what you have either way.

Find out what your
Karnes County minerals
are actually worth.

Send us what you have, or what you think you have. We will pull Texas Railroad Commission records, check operator activity in your section, and put together a plain-English summary with our reasoning laid out. If it makes sense to go further, we move on your timeline. If not, you have a free breakdown you can take anywhere.

Free · No Obligation · Your Timeline