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Texas oil lease

Producing

COX 12-9 UNIT 1

Cox 12-9 Unit 1 is an oil lease in Martin County, Texas, operated by Diamondback E&P LLC in the Spraberry (Trend Area) field.

13 wells

374,423bbl oil, last 12 months−62% vs prior year
Operator
Diamondback E&P LLC
County
Martin County
Field
Spraberry (Trend Area)
RRC lease
08-49245

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Where it sits

This county

Martin CountyMartinGainesAndrewsHowardDawsonBordenMartin County
Martin County
Gas, last 12 months
2,200,215 mcf
Oil in Jul 2026
21,038 bbl

Checks stopped on this lease?

  • Operator

    Operator changed: Diamondback E&P LLC took over from Endeavor Energy Resources L.P. in Jan 2025.

SourceRailroad Commission production, P-5 and P-4 records, data through Jul 2026.

See why checks stop on this lease

Production by month

Oil output fell 62% over the last 12 months

  • Oil (bars)
  • Gas (line)
  • Last 12 months
Oil output fell 62% over the last 12 monthsMonthly oil production and gas for COX 12-9 UNIT 1, Aug 2023 to Jul 2026. Oil output fell 62% over the last 12 months. 374,423 bbl in the 12 months through Jul 2026, against 998,453 bbl in the 12 months before.Last 12 months: 374,423 bblbbl per monthmcf per month0050k100k100k200k150k300k200k400k250k500kOct 23Jan 24AprJulOctJan 25AprJulOctJan 26AprJul
Oil output fell 62% over the last 12 monthsMonthly oil production and gas for COX 12-9 UNIT 1, Aug 2023 to Jul 2026. Oil output fell 62% over the last 12 months. 374,423 bbl in the 12 months through Jul 2026, against 998,453 bbl in the 12 months before.Last 12 monthsbbl per monthmcf per month0050k100k100k200k150k300k200k400k250k500kJan 24JulJan 25JulJan 26Jul

SourceTexas Railroad Commission Production Data Query, through Jul 2026.

Where the gas went

Since Nov 2024 the lease's gas goes to a transmission line instead of a processing plant

Flaring peaked at 3.3% of the gas in Nov 2024.

  • Processing plant (3)
  • Transmission line (2)
  • Lease fuel (1)
  • Flared (4)
Since Nov 2024 the lease's gas goes to a transmission line instead of a processing plantShare of COX 12-9 UNIT 1 gas by disposition code each month, Aug 2023 to Jul 2026. Since Nov 2024 the lease's gas goes to a transmission line instead of a processing plant. Flaring peaked at 3.3% of the gas in Nov 2024.Share of the lease’s gas by disposition code, per month0%50%100%Nov 2024: plant to lineFlared 3.3%Oct 23Jan 24AprJulOctJan 25AprJulOctJan 26AprJul
Since Nov 2024 the lease's gas goes to a transmission line instead of a processing plantShare of COX 12-9 UNIT 1 gas by disposition code each month, Aug 2023 to Jul 2026. Since Nov 2024 the lease's gas goes to a transmission line instead of a processing plant. Flaring peaked at 3.3% of the gas in Nov 2024.Share of gas by disposition code0%50%100%Nov 24: plant to lineFlared 3.3%Jan 24JulJan 25JulJan 26Jul

SourceTexas Railroad Commission Production Data Query, through Jul 2026.

  • Transmission line (2)

    99% · 2,173,441 mcf

  • Lease fuel (1)

    0.8% · 16,688 mcf

  • Flared (4)

    0.5% · 10,086 mcf

0.5% of the gas flared in the last 12 months. One month above 3%.

Who has run this lease

The operator changed once, most recently in Jan 2025

Operators of this lease over timeEndeavor Energy Resources L.P., Jan 2020 to Dec 2024; Diamondback E&P LLC, Jan 2025 to Jul 20262020202120222023202420252026Changed Jan 2025Endeavor Energy Resources L.P.Jan 2020 to Dec 2024Diamondback E&P LLCJan 2025 to now
Operators of this lease over timeEndeavor Energy Resources L.P., Jan 2020 to Dec 2024; Diamondback E&P LLC, Jan 2025 to Jul 20262020202120222023202420252026Changed Jan 2025Endeavor Energy Resources L.P.Jan 2020 to Dec 2024Diamondback E&P LLCJan 2025 to now

SourceTexas Railroad Commission Production Data Query, through Jul 2026.

13 wells on this lease

Wells on COX 12-9 UNIT 1
API numberWell no.Status
42-317-40784222Active
42-317-40785221Active
42-317-45615111Active
42-317-45616112Active
42-317-45617123Active
42-317-45618124Active
42-317-45619125Active
42-317-45620126Active
42-317-45621131Active
42-317-45622141Active
42-317-45623142Active
42-317-45624144Active
42-317-45625243Active

SourceTexas Railroad Commission Wellbore Query.

Buyers and gatherers

Companies named on the Form P-4, by product
CompanyProductRoleShare%FromUntil
Medallion Operating Company, LLCOilGathers100Oct 15, 2024–
Enterprise Products Operating LLCCasinghead gasBuys100Oct 15, 2024–
Enterprise Products Operating LLCCasinghead gasGathers100Oct 15, 2024–
Nustar Permian Trans and Stg,llcOilGathers100Apr 1, 2019Oct 15, 2024
Navitas Mdstr Midland Basin, LLCCasinghead gasGathers100Aug 11, 2017Jul 1, 2019
Navitas Mdstr Midland Basin, LLCCasinghead gasBuys100Aug 11, 2017Jul 1, 2019
Eastex Crude CompanyOilGathers10Aug 11, 2017Apr 1, 2019
Nustar Permian Field Svcs, LLCOilGathers70Aug 11, 2017Apr 1, 2019
Oasis Transp & Marketing Corp.OilGathers10Aug 11, 2017Apr 1, 2019

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

Who buys my oilOil price check

511.39 acres on the newest permit

  • Good to know

    A pooling certificate (P-12) was filed

    Your tract may share its production with neighbors in a pooled unit. The unit acres the operator uses to divide production can differ from the acreage on one permit.

  • Good to know

    The wells on this lease state different acreage

    The permits state between 499 and 511.39 acres. Use the acres from your own division order for the well you are paid on.

  • Good to know

    13 wells are listed on this lease

    Each well can have its own unit. The decimal for one well does not have to equal the decimal for another.

  • 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 Cox 12-9 Unit 1
API numberWell no.Acreson the permit
42-317-45616112511.39
42-317-45617123511.39
42-317-45618124511.39
42-317-45619125511.39
42-317-45620126511.39
42-317-45621131511.39
42-317-45622141511.39
42-317-45623142511.39
42-317-45624144511.39
42-317-45625243511.39
42-317-45615111511.39
42-317-40784222499

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

Unit decimal checker

What Diamondback Energy, Inc. told investors it received

Diamondback E&P LLC is linked to Diamondback Energy, Inc. (FANG).
Realized prices reported by Diamondback Energy, Inc.
QuarterOil$ per bblFiling
Q2 2026$96.82SEC filing
Q1 2026$73.47SEC filing
Q4 2025$58.00SEC filing
Q3 2025$64.60SEC filing
Q2 2025$63.23SEC filing
Q1 2025$70.95SEC filing

SourceDiamondback Energy, Inc. quarterly reports, SEC EDGAR, company-wide averages before hedging.

Estimate your royalty

36 months, newest first

Ledger for COX 12-9 UNIT 1
MonthOil producedbblOil soldbblGas producedmcfGas soldmcf, codes 2+3FlaredmcfWTI$/bblHenry Hub$/MMBtu
Jul 2026Diamondback E&P21,03821,156158,656157,02938$80.46$2.89
Jun 2026Diamondback E&P22,75522,708160,147158,66544$84.81$3.15
May 2026Diamondback E&P23,40223,536162,251160,61159$102.13$2.94
Apr 2026Diamondback E&P22,66022,679161,019158,27415$100.32$2.77
Mar 2026Diamondback E&P22,37922,521132,637129,1082,478$91.38$3.04
Feb 2026Diamondback E&P29,31529,275163,773162,328386$64.51$3.62
Jan 2026Diamondback E&P27,55928,730164,940162,0222,006$60.04$7.72
Dec 2025Diamondback E&P33,63432,542204,705203,263154$57.97$4.26
Nov 2025Diamondback E&P36,34535,997205,424204,11738$60.06$3.79
Oct 2025Diamondback E&P39,41741,542220,503219,19136$60.89$3.19
Sep 2025Diamondback E&P44,95042,792225,185223,569382$63.96$2.97
Aug 2025Diamondback E&P50,96951,308240,975235,2644,450$64.86$2.91
Jul 2025Diamondback E&P56,01755,851238,094234,61639$68.39$3.20
Jun 2025Diamondback E&P58,17858,099234,864229,5472,189$68.17$3.02
May 2025Diamondback E&P77,57177,556289,035285,391122$62.17$3.12
Apr 2025Diamondback E&P90,16090,230278,482274,1721,059$63.54$3.42
Mar 2025Diamondback E&P121,316121,279333,234328,108149$68.24$4.12
Feb 2025Diamondback E&P146,435146,451316,160310,876148$71.53$4.19
Jan 2025Diamondback E&P222,493224,297311,891305,71478$75.74$4.13
Dec 2024Endeavor Energy182,905181,962189,725184,37415$70.12$3.01
Nov 2024Endeavor Energy34,79733,57134,88030,7751,134$69.95$2.12
Oct 2024Endeavor Energy9422213130$71.99$2.20
Sep 2024Endeavor Energy3,8663,6699,3279,3270$70.24$2.28
Aug 2024Endeavor Energy4,6214,8249,6669,6660$76.68$1.99
Jul 2024Endeavor Energy3,6723,6753,5873,5870$81.80$2.07
Jun 2024Endeavor Energy4,8885,2129,5109,5100$79.77$2.54
May 2024Endeavor Energy3,5543,1875,7545,7540$80.02$2.12
Apr 2024Endeavor Energy2,6472,6086,1296,1236$85.35$1.60
Mar 2024Endeavor Energy4,3014,4606,2596,2590$81.28$1.49
Feb 2024Endeavor Energy4,1054,0733,7953,70194$77.25$1.72
Jan 2024Endeavor Energy3,1853,1952,5032,5030$74.15$3.18
Dec 2023Endeavor Energy5,0024,7687,7087,7080$71.90$2.52
Nov 2023Endeavor Energy5,5625,8257,9427,9420$77.69$2.71
Oct 2023Endeavor Energy4,0383,6253,8843,8840$85.64$2.98
Sep 2023Endeavor Energy1,4742,0315,8575,8570$89.43$2.64
Aug 2023Endeavor Energy6,7576,50516,50916,5090$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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This lease belongs to

OperatorDiamondback E&P LLCFieldSpraberry (Trend Area)CountyMartin County

Diamondback E&P LLC in Martin County

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