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Producing

GUAJILLO UNIT 13 SOUTH

Guajillo Unit 13 South is an oil lease in Atascosa County, Texas, operated by Marathon Oil Ef LLC in the Eagleville (Eagle Ford-1) field.

4 wells

52,067bbl oil, last 12 months−21% vs prior year
Operator
Marathon Oil Ef LLC
County
Atascosa County
Field
Eagleville (Eagle Ford-1)
RRC lease
01-20460

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Where it sits

This county

Atascosa CountyAtascosaWilsonMedinaKarnesFrioBexarAtascosa County
Atascosa County
Gas, last 12 months
66,952 mcf
Oil in Jul 2026
4,899 bbl

Production by month

Oil output fell 21% over the last 12 months

  • Oil (bars)
  • Gas (line)
  • Last 12 months
Oil output fell 21% over the last 12 monthsMonthly oil production and gas for GUAJILLO UNIT 13 SOUTH, Aug 2023 to Jul 2026. Oil output fell 21% over the last 12 months. 52,067 bbl in the 12 months through Jul 2026, against 65,843 bbl in the 12 months before.Last 12 months: 52,067 bblbbl per monthmcf per month002,5005,0005,00010k7,50015k10k20kOct 23Jan 24AprJulOctJan 25AprJulOctJan 26AprJul
Oil output fell 21% over the last 12 monthsMonthly oil production and gas for GUAJILLO UNIT 13 SOUTH, Aug 2023 to Jul 2026. Oil output fell 21% over the last 12 months. 52,067 bbl in the 12 months through Jul 2026, against 65,843 bbl in the 12 months before.Last 12 monthsbbl per monthmcf per month002,5005,0005,00010k7,50015k10k20kJan 24JulJan 25JulJan 26Jul

SourceTexas Railroad Commission Production Data Query, through Jul 2026.

Where the gas went

69% of the gas went to a processing plant in the last 12 months

Flaring peaked at 4.3% of the gas in Aug 2025.

  • Processing plant (3)
  • Lease fuel (1)
  • Flared (4)
69% of the gas went to a processing plant in the last 12 monthsShare of GUAJILLO UNIT 13 SOUTH gas by disposition code each month, Aug 2023 to Jul 2026. 69% of the gas went to a processing plant in the last 12 months. Flaring peaked at 4.3% of the gas in Aug 2025.Share of the lease’s gas by disposition code, per month0%50%100%Flared 4.3%Oct 23Jan 24AprJulOctJan 25AprJulOctJan 26AprJul
69% of the gas went to a processing plant in the last 12 monthsShare of GUAJILLO UNIT 13 SOUTH gas by disposition code each month, Aug 2023 to Jul 2026. 69% of the gas went to a processing plant in the last 12 months. Flaring peaked at 4.3% of the gas in Aug 2025.Share of gas by disposition code0%50%100%Flared 4.3%Jan 24JulJan 25JulJan 26Jul

SourceTexas Railroad Commission Production Data Query, through Jul 2026.

  • Processing plant (3)

    69% · 46,343 mcf

  • Lease fuel (1)

    29% · 19,448 mcf

  • Flared (4)

    1.7% · 1,161 mcf

1.7% of the gas flared in the last 12 months. 6 months above 3%.

4 wells on this lease

Wells on GUAJILLO UNIT 13 SOUTH
API numberWell no.Status
42-013-358411HActive
42-013-358422HActive
42-013-358433HActive
42-013-358444HActive

SourceTexas Railroad Commission Wellbore Query.

Buyers and gatherers

Companies named on the Form P-4, by product
CompanyProductRoleShare%FromUntil
Enterprise Crude Oil LLCOilGathers25Jul 1, 2022–
Harvest Midstream CompanyOilGathers25Jul 1, 2022–
Reynolds Energy Transport LLCOilGathers25Jul 1, 2022–
Trafigura Trading LLCOilGathers25Jul 1, 2022–
Marathon Oil Ef LLCCasinghead gasBuys100Jul 4, 2021–
Marathon Oil Ef LLCCasinghead gasGathers100Jul 4, 2021–
Enterprise Crude Oil LLCOilGathers1Jul 4, 2021Jul 1, 2022
Gulfmark Energy, Inc.OilGathers1Jul 4, 2021Jul 1, 2022
Harvest Midstream CompanyOilGathers97Jul 4, 2021Jul 1, 2022
Trafigura Trading LLCOilGathers1Jul 4, 2021Jul 1, 2022

SourceRailroad Commission Form P-4 file, Sep 24, 2026 (source).

Who buys my oilOil price check

187.50 acres on the newest permit

  • Worth asking

    A Rule 37 case is listed

    The RRC permit records list a Rule 37 case. This does not establish your royalty share. Ask for the permit and unit plat for your well.

Check your decimal on this lease
Permits for Guajillo Unit 13 South
API numberWell no.Acreson the permit
42-013-358411H187.50
42-013-358422H187.50
42-013-358433H187.50
42-013-358444H187.50

SourceRailroad Commission drilling permits, Oct 3, 2026 (source 1, source 2).

Unit decimal checker

What ConocoPhillips told investors it received

Marathon Oil Ef LLC is linked to ConocoPhillips (MRO).
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, SEC EDGAR, company-wide averages before hedging.

Estimate your royalty

36 months, newest first

Ledger for GUAJILLO UNIT 13 SOUTH
MonthOil producedbblOil soldbblGas producedmcfGas soldmcf, codes 2+3FlaredmcfWTI$/bblHenry Hub$/MMBtu
Jul 20264,8994,9156,9884,57684$80.46$2.89
Jun 20264,7564,7534,6583,12047$84.81$3.15
May 20264,8624,8646,9504,849116$102.13$2.94
Apr 20265,3895,4188,1595,83071$100.32$2.77
Mar 20264,4284,3774,2732,91587$91.38$3.04
Feb 20263,5743,5186,5584,66179$64.51$3.62
Jan 20263,6773,6695,2143,66234$60.04$7.72
Dec 20254,2424,2326,0074,33743$57.97$4.26
Nov 20254,0404,0444,2312,948151$60.06$3.79
Oct 20254,0564,0623,7382,74753$60.89$3.19
Sep 20254,0754,0624,1572,880140$63.96$2.97
Aug 20254,0694,0816,0193,818256$64.86$2.91
Jul 20254,7094,7028,5195,322159$68.39$3.20
Jun 20254,7854,7958,2865,014226$68.17$3.02
May 20255,3875,4139,0885,542232$62.17$3.12
Apr 20255,2355,2035,4003,397109$63.54$3.42
Mar 20255,9685,9626,8064,420139$68.24$4.12
Feb 20255,2555,2668,6505,637108$71.53$4.19
Jan 20255,5685,5309,9146,410315$75.74$4.13
Dec 20245,4345,43611,6417,846222$70.12$3.01
Nov 20246,0726,06412,0378,457210$69.95$2.12
Oct 20246,3556,36211,5868,539182$71.99$2.20
Sep 20245,2865,2979,7147,418156$70.24$2.28
Aug 20245,7895,78512,5259,686128$76.68$1.99
Jul 20246,4446,44014,04811,075121$81.80$2.07
Jun 20245,3045,3628,4066,220139$79.77$2.54
May 20247,7247,70812,3416,825316$80.02$2.12
Apr 20246,6036,6089,9074,998347$85.35$1.60
Mar 20247,5527,54013,9478,087155$81.28$1.49
Feb 20248,3108,32210,7867,776125$77.25$1.72
Jan 20247,8147,8249,2916,103172$74.15$3.18
Dec 20237,5497,54112,1608,966161$71.90$2.52
Nov 20237,8277,80516,04812,718179$77.69$2.71
Oct 20237,7007,70016,19612,712248$85.64$2.98
Sep 20237,2407,24611,5658,179410$89.43$2.64
Aug 20238,1428,14715,56512,225168$81.39$2.58

Flared above 3%

SourceTexas Railroad Commission Production Data Query, through Jul 2026. Prices: EIA, through Aug 2026. Updated Oct 2, 2026.

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Nearby

This lease belongs to

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

Marathon Oil Ef LLC in Atascosa County

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Eagleville (Eagle Ford-1) field

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