WELL · 42-335-31543 · DISTRICT 8
Westbrook Southwest Unit #4-21
Mitchell County · Westbrook field · Vertical
Westbrook Southwest Unit #4-21 (API 42-335-31543) is a plugged well in Mitchell County, plugged April 8, 2025, last operated by Grayrock Energy II LLC.
The RRC has issued one drilling permit, issued November 9, 1979, permitted to 3,350 ft.
It was permitted by Union Texas Petroleum Corp. and has since transferred to Grayrock Energy II LLC on the wellbore schedule.
Completion filings report 3 formation tops, including Redbed, Limesand, Dolamite.
Its lease has reported 8.65M barrels of oil and 21 mcf of gas since January 1993, last reporting in July 2026. The lease carries 371 wells, so these are lease totals, not this well alone.
Operator of record
Permitted by Union Texas Petroleum Corp.; the EWA schedule now lists a different operator.
Fort Worth, TX · P-5 Y, filed Aug 4, 2025 · (214) 234-9115
SOURCE · RRC EWA WELLBORE SCHEDULE
What each RRC source says
| Wellbore schedule | Grayrock Energy II LLC |
| Production reports | Grayrock Energy II, LLCthrough Apr 2026 |
| Latest permit | Union Texas Petroleum Corp.Nov 9, 1979 |
The sources disagree, which usually means a transfer or a lease-level production filing by a different entity. Petrora goes with the schedule.
- 3,350
- total depth, ft
- 1
- permits on file
- Nov 9, 1979
- last permit issued
- Jan 24, 2014
- completed
- 8.65M
- cumulative oil, bbl
- 21
- cumulative gas, mcf
PRODUCTION FROM PDQ LEASE REPORTS · Jan 1993 THROUGH Jul 2026
Regulatory status · RRC wellbore file
- Schedule
- OFF SCHEDULE
- Completed
- Jan 24, 2014
- Shut in
- —
- Plugged
- Apr 8, 2025
Surface location
No coordinates on the permit record yet. The RRC's GIS record usually lands within days of issuance; historical master-file permits never carry one.
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 371 wells in total, so volumes are shared.Why →
| Lease | Field | Reporting operator | Wells | Oil, bbl | Gas, mcf | Reported |
|---|---|---|---|---|---|---|
| Westbrook Southwest Unit O-10-21120 | Westbrook | Grayrock Energy II, LLC | 371 | 8.65M | 21 | Jan 1993 – Jul 2026 |
Oil, barrels lease total
Last 12 months 130,319 · prior 12 134,739(-3%)
Chain of custody
Every operator that reported production on this well's lease, in order.
- 1Meridian Oil Inc.Jan 1993 → Jul 1996
- 2Burlington Resources Oil&gas Co.Aug 1996 → Apr 1997
- 3Gruy Petroleum Management Co.May 1997 → Apr 2006
- 4Cimarex Energy Co. of ColoradoMay 2006 → Sep 2009
- 5Merit Energy CompanyOct 2009 → May 2017
- 6Rover Petroleum Operating, LLCJun 2017 → Dec 2023
- 7Grayrock Energy II, LLCJan 2024 → Apr 2026
Permits
| Permit | Type | Operator | Received | Issued | Spud | Depth |
|---|---|---|---|---|---|---|
| 63731-99 | Drill | Union Texas Petroleum Corp. | Nov 9, 1979 | Nov 9, 1979 | Nov 20, 1979 | 3,350 |
Completions
| Completed | Lease | Field | Operator | Status | Depth |
|---|---|---|---|---|---|
| — | — O-10-21120 | — | — | — | — |
Formation tops
As filed on W-2/G-1. Subsea from 2,148 ft elevation.Download CSV →
| Formation | MD ft | Subsea |
|---|---|---|
| Redbed | 810 | 1,338 |
| Limesand | 1,738 | 410 |
| Dolamite | — | — |
Perforations
Perforated and open-hole intervals.
| From | To | Type |
|---|---|---|
| 2,994 | 3,208 | Perforated |
| 2,994 | 3,209 | Perforated |
Casing
Strings as reported, shallowest first.
| Casing in | Set at | Hole in | Cement |
|---|---|---|---|
| 10.75 | 306 | 14 | 250 S |
| 10.75 | 307 | 14 | 250 S |
| 2.375 | 3,100 | — | — |
| 5.5 | 3,290 | 7.875 | 633 S |
| 5.5 | 3,300 | 7.875 | 633 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 →
| Suffix | Filed | W-2 / G-1 date | Logs referenced |
|---|---|---|---|
| 00 | Aug 29, 2014 | Apr 11, 2014 | — |
| 00 | Mar 14, 1990 | Feb 13, 1990 | — |
| 00 | Jan 12, 1984 | Dec 28, 1979 | — |
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.
- Wellbore filings for 42-335-31543 → W-2, G-1, plugging reports, as PDFs
- Completion packets for 42-335-31543 → scanned completion filings
Log images are in archives with no per-well link: the RRC's Neubus archive (2004 onward). then paste it into their search.
Beyond the permit record
RRC UIC permits · H-10 reported volumes
Injection
- 0
- bbl, last 12 reported months
- 3.12M
- bbl, all reported
- Jan 2025
- reported through
| UIC | Kind | Status | Permitted bbl/d | Max psi | Zone ft |
|---|---|---|---|---|---|
| 000071301 | H-1 Injection | Plugged Apr 10, 2025 | 700 | 1,100 | 2,300–3,300 |
MONTHLY INJECTED, BBL · H-10 · LAST 24 REPORTED MONTHS
Last 12 months 0 · prior 12 119,516(-100%)
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/33531543, documented in the API reference.