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Royalty Clerk

Texas oil lease · RRC district 01 · Lease 21791

Producing

MCS FOUNDATION UNIT

MCS Foundation Unit is an oil lease in Atascosa County, Texas, operated by Marathon Oil Ef LLC in the Eagleville (Eagle Ford-1) field. The Railroad Commission shows 384,325 bbl of oil in the 12 months through Jul 2026.

Oil lease dossier · 3 wells

384,325bbl oil, last 12 months
Operator
Marathon Oil Ef LLC
County
Atascosa County
Field
Eagleville (Eagle Ford-1)
RRC lease
01-21791

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Where it sits

This county

Atascosa CountyAtascosaWilsonMedinaKarnesFrioBexarAtascosa County
Atascosa County · RRC district 01Open Atascosa County →
Gas, last 12 months
437,213 mcf
Oil in Jul 2026
13,411 bbl
Reporting to the state
since Jul 2025
Wells
3

Production

Month by month, from the state record

What the Railroad Commission says this oil lease produced. Oil is in barrels (bbl). Gas is in thousand cubic feet (mcf).

Oil output fell 73% since Jul 2025

Monthly average of 16,343 bbl in the latest 3 months, against 61,663 bbl in the first 3.

  • Oil (bars, left axis)
  • Gas (line, right axis)
Oil output fell 73% since Jul 2025Monthly oil production and gas for MCS FOUNDATION UNIT, Jul 2025 to Jul 2026. Oil output fell 73% since Jul 2025. Monthly average of 16,343 bbl in the latest 3 months, against 61,663 bbl in the first 3.bbl per monthmcf per month0025k20k50k40k75k60k100k80kJul 25OctJan 26AprJul
Oil output fell 73% since Jul 2025Monthly oil production and gas for MCS FOUNDATION UNIT, Jul 2025 to Jul 2026. Oil output fell 73% since Jul 2025. Monthly average of 16,343 bbl in the latest 3 months, against 61,663 bbl in the first 3.bbl per monthmcf per month0025k20k50k40k75k60k100k80kJul 25Jan 26Jul

SourceTexas Railroad Commission Production Data Query, oil lease 21791, district 01. Reported through Jul 2026. The state revises recent months.

Gas disposition

Where the gas went

Every month the operator tells the state where each mcf of gas went, using a code. The code decides how your gas is paid.

86% of the gas went to a processing plant in the last 12 months

Flaring peaked at 3.8% of the gas in Jul 2025.

  • Processing plant (3)
  • Lease fuel (1)
  • Flared (4)
86% of the gas went to a processing plant in the last 12 monthsShare of MCS FOUNDATION UNIT gas by disposition code each month, Jul 2025 to Jul 2026. 86% of the gas went to a processing plant in the last 12 months. Flaring peaked at 3.8% of the gas in Jul 2025.Share of the lease’s gas by disposition code, per month0%50%100%Flared 3.8%Jul 25OctJan 26AprJul
86% of the gas went to a processing plant in the last 12 monthsShare of MCS FOUNDATION UNIT gas by disposition code each month, Jul 2025 to Jul 2026. 86% of the gas went to a processing plant in the last 12 months. Flaring peaked at 3.8% of the gas in Jul 2025.Share of gas by disposition code0%50%100%Flared 3.8%Jul 25Jan 26Jul

SourceTexas Railroad Commission Production Data Query, gas disposition by code, lease 21791, district 01. Reported through Jul 2026.

Processing plant (3)

Sent to a gas plant that pulls out natural gas liquids. Your statement should show plant products, and may show processing fees.

Lease fuel (1)

Burned to run equipment on the lease. Not sold, so it pays no royalty. A few percent is normal.

Flared (4)

Burned off or vented, not sold. It pays no royalty. More than 3% in a month is worth watching.

Over the last 12 months, 1.4% of the gas was flared. 2 months went above 3%, which we mark in the ledger below.

Operator history

Who has run this lease

The operator runs the wells and pays your royalty. When the operator changes, payments often slip for a month or two.

Marathon Oil Ef LLC has reported this lease for the whole period

No change of operator in the months we hold.

Operators of this lease over timeMarathon Oil Ef LLC, Jul 2025 to Jul 20262026Marathon Oil Ef LLCJul 2025 to nowthrough Jul 2026
Operators of this lease over timeMarathon Oil Ef LLC, Jul 2025 to Jul 20262026Marathon Oil Ef LLCJul 2025 to nowthrough Jul 2026

SourceTexas Railroad Commission Production Data Query, operator by month. Reported through Jul 2026.

Wells

3 wells on this lease

Every well the Railroad Commission links to oil lease 21791 in district 01. The API number is the state’s ID for a well.
Wells on MCS FOUNDATION UNIT
API numberWell no.Status
42-013-362207HActive
42-013-362218HActive
42-013-362229HActive

SourceTexas Railroad Commission Wellbore Query, district 01, lease 21791.

Who buys and gathers

Who moves and buys this lease's production

The operator files a Form P-4 with the Railroad Commission naming the companies authorised to gather and buy the oil and gas. The buyer's price is the one your royalty is figured on.

  • Oil

    Statewide Crude Inc. and Gulfmark Energy, Inc. gather it.

    Statewide Crude Inc. gathers it: 90% of it, on the list since Jul 19, 2025 · Gulfmark Energy, Inc. gathers it: 10% of it, on the list since Jul 19, 2025

  • Gas from oil wells

    Marathon Oil Ef LLC buys and gathers it.

    Marathon Oil Ef LLC buys it: 100% of it, on the list since Jul 19, 2025 · Marathon Oil Ef LLC gathers it: 100% of it, on the list since Jul 19, 2025

SourceRailroad Commission of Texas, Form P-4 file, dated Sep 24, 2026 (source). A listed company is authorised to move or buy the production; the state does not say what it paid.

Who buys my oil and gasIs my oil price fair?

Unit and wells

2,141.85 acres on the newest permit

Acres and wells as the operator filed them on its Railroad Commission drilling permits. Your decimal is your net acres over the unit acres, so this is the number to hold your division order against.
Wells on the permits
33 not plugged
Horizontal
3
First completion
Jul 19, 2025
Latest permit
Jan 23, 2025
Wells and acres on the permits for MCS Foundation Unit
API numberWell no.Acreson the permit
42-013-362207H2,141.85
42-013-362218H2,141.85
42-013-362229H2,141.85

SourceRailroad Commission of Texas, drilling permits and wellbore file, Sep 26, 2026 (source 1, source 2). The acres are what the operator filed; they are not a survey.

Check my decimal against the unit

What the operator reported

What ConocoPhillips told investors it received

Marathon Oil Ef LLC is linked to ConocoPhillips (MRO). Public companies report the average price they realize each quarter. It is an average across everything the company operates, not the price on this lease.
Realized prices reported by ConocoPhillips
QuarterOil$ per bblFiling
Q2 2026$99.40SEC filing
Q1 2026$73.47SEC filing
Q3 2025$66.13SEC filing
Q2 2025$64.23SEC filing
Q1 2025$71.65SEC filing

SourceConocoPhillips quarterly reports on SEC EDGAR, prices before hedging where the company states both. Read by machine from each filing’s tables; the link opens the filing so you can check the figure.

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Estimator

Estimate your royalty for this lease

A rough check before you look at a statement: the state volumes times your decimal, priced at WTI and Henry Hub.

Estimator

What could your check be?

Your decimal interest is the small number on your division order that says what share of the whole lease (8/8ths) is yours. Type it in and we apply it to what the state says MCS FOUNDATION UNIT sold each month.

For example 0.00097656, or a fraction like 1/1024.

Dollars per barrel. Your statements show the gap your operator uses. Leave 0 to price oil at WTI.

Your estimate appears here

Enter your decimal to see an estimated royalty for each of the last 12 months this lease reported. Nothing you type leaves your browser.

An estimate, not your check

It ignores gathering and processing fees, taxes, plant products and the price your operator actually gets, so your statement will differ. Use it as a ceiling to compare against. Regional gas prices are often below Henry Hub.

Ledger

13 months, newest first

Compare these numbers with your statements. Your share of a month is the “Oil sold” volume times your decimal. Scroll sideways on a phone.
Monthly production, disposition and prices for MCS FOUNDATION UNIT
MonthOil producedbblOil soldbblGas producedmcfGas soldmcf, codes 2+3Flaredmcf, code 4WTI$ per bblHenry Hub$ per MMBtu
Jul 2026Marathon Oil13,41113,75819,77817,034159$80.46$2.89
Jun 2026Marathon Oil15,42315,50114,40512,411151$84.81$3.15
May 2026Marathon Oil20,19420,19827,09523,710218$102.13$2.94
Apr 2026Marathon Oil18,89718,87924,62921,138247$100.32$2.77
Mar 2026Marathon Oil22,18322,07532,49128,498241$91.38$3.04
Feb 2026Marathon Oil21,50421,42931,55227,321239$64.51$3.62
Jan 2026Marathon Oil25,94226,13134,04229,864221$60.04$7.72
Dec 2025Marathon Oil30,60630,56236,37531,092230$57.97$4.26
Nov 2025Marathon Oil35,46335,54845,76539,906251$60.06$3.79
Oct 2025Marathon Oil44,43244,28848,51741,625635$60.89$3.19
Sep 2025Marathon Oil52,69053,07751,50843,2761,146$63.96$2.97
Aug 2025Marathon Oil83,58083,38371,05659,7642,545$64.86$2.91
Jul 2025Marathon Oil48,71847,97737,18529,3651,396$68.39$3.20

No report filed More than 3% of gas flared

SourceVolumes: Texas Railroad Commission Production Data Query, reported through Jul 2026. Prices: EIA WTI Cushing spot and Henry Hub spot, monthly, through Aug 2026. “Gas sold” is gas sent to a transmission line (code 2) or a plant (code 3).

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Around this lease

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Everything on this page connects to the operator, field and county records. Start from any of them.

This lease belongs to

OperatorMarathon Oil Ef LLCFieldEagleville (Eagle Ford-1)CountyAtascosa County

Marathon Oil Ef LLC in Atascosa County

All Marathon Oil Ef LLC leases →

Eagleville (Eagle Ford-1) field

All leases in this field →

Leases within 10 km

Found by the location of their wells.

Drilling permits within 10 km

How to read this page

Questions owners ask

What is a decimal interest?

It is your share of the whole lease, written as a decimal. A 1/4 royalty on 5 net acres in a 1,280-acre unit is 1/4 × 5 ÷ 1,280 = 0.00097656. Your division order states yours.

How do I use this page to check a royalty check?

Take the “Oil sold” volume for the month the check covers and multiply it by your decimal. The answer should match the barrels on your statement. If it does not, upload the statement and we will show where the two differ.

Why is the newest month Jul 2026?

The Railroad Commission publishes production two to three months after the fact and revises recent months. We re-pull the latest three months on every update.

Does this page show what my check should be?

No. It shows what the state recorded. Prices, fees and taxes depend on your lease and on what your operator gets for the oil and gas. The estimator gives a ceiling to compare against.

Sources and method

Where these numbers come from

  • Production and disposition by month: Texas Railroad Commission Production Data Query, oil lease 21791, district 01, reported through Jul 2026.
  • Wells: Texas Railroad Commission Wellbore Query.
  • Prices: U.S. Energy Information Administration, WTI Cushing spot and Henry Hub spot, monthly.
  • Page updated Sep 28, 2026.

We show the state’s numbers as filed. Where the state has no report for a month, we say so instead of guessing.