WELL · 42-317-45617 · DISTRICT 8

Cox 12-9 Unit 1 #123

Y

Martin County · Spraberry (Trend Area) field · Shut IN  · Horizontal

Cox 12-9 Unit 1 #123 (API 42-317-45617) is a horizontal well in Martin County operated by Diamondback E&P LLC, completed November 9, 2024 and listed as shut in on the RRC schedule.

The RRC has issued one drilling permit, issued September 25, 2023, permitted to 10,802 ft.

It was permitted by Endeavor Energy Resources L.P. and has since transferred to Diamondback E&P LLC on the wellbore schedule.

Completion filings report 16 formation tops, including Santa Rosa, Yates, Queen, Grayburg.

Its lease has reported 2.08M barrels of oil and 5.16M mcf of gas since August 2017, last reporting in July 2026. The lease carries 13 wells, so these are lease totals, not this well alone.

Operator of record

Diamondback E&P LLC

Permitted by Endeavor Energy Resources L.P.; the EWA schedule now lists a different operator.

Midland, TX · P-5 Y, filed Mar 4, 2026 · 5,231 permits on file · (855) 247-5920

SOURCE · RRC EWA WELLBORE SCHEDULE

What each RRC source says

Wellbore scheduleDiamondback E&P LLC
Production reportsDiamondback E&P LLCthrough Apr 2026
Latest permitEndeavor Energy Resources L.P.Sep 25, 2023

The sources disagree, which usually means a transfer or a lease-level production filing by a different entity. Petrora goes with the schedule.

10,802
total depth, ft
1
permits on file
Sep 25, 2023
last permit issued
Nov 9, 2024
completed
2.08M
cumulative oil, bbl
5.16M
cumulative gas, mcf

PRODUCTION FROM PDQ LEASE REPORTS · Aug 2017 THROUGH Jul 2026

Regulatory status · RRC wellbore file

Schedule
ON SCHEDULE
Completed
Nov 9, 2024
Shut in
—
Plugged
—

Operator's P-5 on the schedule: X

Surface location

32.303005, -102.004439

OpenStreetMap → ·  Google Maps →

Permit surface location from the RRC GIS record, in Martin County.

Lease production

PDQ LEASE REPORTS · REPORTED THROUGH APR 2026

Texas reports oil by lease, not by well. These are the lease this well is completed on; they carry 13 wells in total, so volumes are shared.Why →

LeaseFieldReporting operatorWellsOil, bblGas, mcfReported
Cox 12-9 Unit 1 O-10-49245Spraberry (Trend Area)Diamondback E&P LLC132.08M5.16MAug 2017 – Jul 2026

Oil, barrels lease total

Last 12 months 498,220 · prior 12 818,801(-39%)

0100K200K300K202420252026

Gas, mcf lease total

Last 12 months 2,481,154 · prior 12 1,502,229(+65%)

0200K400K202420252026

Chain of custody

Every operator that reported production on this well's lease, in order.

  1. 1Endeavor Energy Resources L.P.Aug 2017 → Dec 2024
  2. 2Diamondback E&P LLCJan 2025 → Apr 2026

Permits

PermitTypeOperatorReceivedIssuedSpudDepth
893731-99DrillEndeavor Energy Resources L.P.Sep 14, 2023Sep 25, 2023Nov 27, 202310,802

Completions

CompletedLeaseFieldOperatorStatusDepth
—— O-10-49245————

Formation tops

As filed on W-2/G-1. Subsea from 2,826 ft elevation.Download CSV →

FormationMD ftSubsea
Santa Rosa1,0001,826
Yates2,75571
Queen3,619-793
Grayburg3,970-1,144
San AndresSAN ANDRES - ACTIVE CO2 FLOOD; H4,731-1,905
Spraberry7,791-4,965
Cisco——
Dean——
Devonian——
Ellenburger——
Fusselman——
Mississippian——
Pennsylvanian——
Precambrian (Undifferentiated)——
Silurian (undifferentiated)SILURIAN——
Wolfcamp——

Perforations

Perforated and open-hole intervals.

FromToType
8,80116,240Perforated

Casing

Strings as reported, shallowest first.

Casing inSet atHole inCement
13.3751,94217.51,175 S
9.6256,67512.251,880 S
5.516,2668.51,920 S

Completion filings

W-2 and G-1 reports on record in the RRC wellbore file, newest first. The suffix identifies the wellbore or completion event. About these reports →

SuffixFiledW-2 / G-1 dateLogs referenced
00May 19, 2025Mar 14, 2025—
00Sep 19, 2024Jun 27, 2024Yes

The source documents

Petrora holds the structured record. The scanned filings live at the RRC; these links open its search already filled in for this API.

Log images are in archives with no per-well link: the RRC's Neubus archive (2004 onward) and the University Lands library. then paste it into their search.

Nearby wells and their tops

NEAREST 8 LOCATED WELLS WITH TOPS · WITHIN 16 KM

Draw a cross-section

This well's tops beside its 5 nearest neighbours, subsea-aligned so they line up regardless of surface terrain.

Open the cross-section →

Cox 12-9 Unit 142-317-45616

0.0 KM · Endeavor Energy Resources L.P. · Section with this well →

Santa Rosa1,0001,826
Yates2,75571
Queen3,620-794
Grayburg3,792-966
San Andres4,732-1,906
Clear Fork6,481-3,655
Spraberry7,805-4,979
Cisco—

11 TOPS · FIRST 8

Cox 12-9 Unit 142-317-45620

0.0 KM · Endeavor Energy Resources L.P. · Section with this well →

Santa Rosa1,0001,826
Yates2,75571
Queen3,620-794
Grayburg3,973-1,147
San Andres4,732-1,906
Clear Fork6,472-3,646
Spraberry7,791-4,965
Wolfcamp—

11 TOPS · FIRST 8

Cox 12-9 Unit 142-317-45615

0.0 KM · Endeavor Energy Resources L.P. · Section with this well →

Santa Rosa1,0001,826
Yates2,75769
Queen3,604-778
Grayburg3,982-1,156
San Andres4,733-1,907
Spraberry7,779-4,953
Cisco—
Dean—

10 TOPS · FIRST 8

Cox 12-9 Unit 142-317-45619

0.0 KM · Endeavor Energy Resources L.P. · Section with this well →

Santa Rosa1,0001,826
Yates2,75373
Queen3,617-791
Grayburg3,968-1,142
San Andres4,725-1,899
Clear Fork6,470-3,644
Spraberry7,789-4,963
Pennsylvanian—

11 TOPS · FIRST 8

Cox 12-9 Unit 142-317-45618

0.0 KM · Endeavor Energy Resources L.P. · Section with this well →

Santa Rosa1,0001,826
Yates2,75472
Queen3,620-794
Grayburg3,972-1,146
San Andres4,732-1,906
Clear Fork6,472-3,646
Spraberry7,794-4,968
Cisco—

12 TOPS · FIRST 8

Pier 21-24 B42-317-42242

0.0 KM · Endeavor Energy Resources L.P. · Section with this well →

Santa Rosa1,0001,823
Yates1,846977
Queen2,300523
Grayburg4,243-1,420
San Andres4,466-1,643
Cisco6,476-3,653
Spraberry8,079-5,256
Dean—

10 TOPS · FIRST 8

Pier 21-24 B42-317-42241

0.0 KM · Endeavor Energy Resources L.P. · Section with this well →

Santa Rosa1,0001,823
Yates1,846977
Queen2,300523
Grayburg4,243-1,420
San Andres4,466-1,643
Cisco6,476-3,653
Spraberry7,840-5,017
Wolfcamp—

10 TOPS · FIRST 8

Pier 21-24 B42-317-42239

0.0 KM · Endeavor Energy Resources L.P. · Section with this well →

Santa Rosa1,0001,827
Yates1,846981
Queen2,300527
Grayburg4,243-1,416
San Andres4,466-1,639
Cisco6,476-3,649
Spraberry8,089-5,262
Dean9,154-6,327

10 TOPS · FIRST 8

About this data

Permits from the RRC OGA049M master and daily daf420 files; wellbore and operator of record from the EWA schedule, weekly; completions, formation tops, casing, and perforations from the dbf900 wellbore file; production from PDQ lease reports, which lag two to three months; injection from UIC permits, H-10 reports, and TexNet daily volumes; earthquakes from the TexNet catalog.

New to these records? How to read a well page · API numbers · completion reports and tops · why production is by lease

Developers: this page as JSON is GET /v1/data/wells/31745617, documented in the API reference.