TEXAS · WELLS · MARTIN COUNTY · COX LEASE · API 42-317-36220 · DISTRICT 7B
Cox #4
Martin County · Spraberry (Trend Area) field · Producing · Vertical
Cox #4 (API 42-317-36220) is a well in Martin County operated by Xto Energy Inc., completed March 11, 2012 and listed as producing on the RRC schedule.
The RRC has issued one drilling permit (amended once), issued August 13, 2010, permitted to 11,550 ft.
It was permitted by Berry Oil Comp. and has since transferred to Xto Energy Inc. on the wellbore schedule.
Completion filings report 5 formation tops, including Clear Fork, Spraberry, Dean, Wolfcamp.
Its lease has reported 17.2K barrels of oil and 15.9K mcf of gas since March 2011, last reporting volume in August 2025.
Operator of record
Permitted by Berry Oil Comp.; the EWA schedule now lists a different operator.
- Based in
- Spring, TX
- P-5 status
- Active – Extension (X)
- P-5 last filed
- Apr 8, 2026
- Permits on file
- 16,156
- Phone
- (346) 502-1572
SOURCE · RRC EWA WELLBORE SCHEDULE
What each RRC source says
| Wellbore schedule | XTO Energy Inc. |
| Production reports | XTO Energy Inc.through Aug 2025 |
| Latest permit | Berry Oil Comp.Aug 13, 2010 |
The sources disagree, which usually means a transfer or a lease-level production filing by a different entity. Petrora goes with the schedule.
- 11,550
- total depth, ft
- 2
- permits on file
- Aug 13, 2010
- last permit issued
- Mar 11, 2012
- completed
- 17.2K
- cumulative oil, bbl
- 15.9K
- cumulative gas, mcf
PRODUCTION FROM PDQ LEASE REPORTS · Apr 2011 THROUGH Aug 2025
Regulatory status · RRC wellbore file
- Schedule
- ON SCHEDULE
- Completed
- Mar 11, 2012
- Shut in
- —
- Plugged
- —
Operator's P-5 on the schedule: Active (A)
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; this well is the only one on it.Why →
| Lease | Field | Reporting operator | Wells | Oil, bbl | Gas, mcf | Reported |
|---|---|---|---|---|---|---|
| Cox O-10-42095 | Spraberry (Trend Area) | XTO Energy Inc. | 1 | 17.2K | 15.9K | Mar 2011 – Aug 2025 |
Oil, barrels lease total
Last 12 months 142 · prior 12 515(-72%)
Gas, mcf lease total
Last 12 months 0 · prior 12 15(-100%)
Chain of custody
Every operator that reported production on this well's lease, in order.
- 1Berry Oil Comp.Apr 2011 → Jun 2014
- 2Linn Operating, Inc.Jul 2014 → Oct 2014
- 3XTO Energy Inc.Dec 2014 → Aug 2025
Permits
| Permit | Type | Operator | Received | Issued | Spud | Depth |
|---|---|---|---|---|---|---|
| 700608-98 | Drill | Berry Oil Comp. | Dec 30, 2010 | Aug 13, 2010 | Feb 17, 2011 | 12,000 |
| 700608-99 | Drill | Berry Oil Comp. | Aug 12, 2010 | Aug 13, 2010 | — | 12,000 |
Completions
| Completed | Lease | Field | Operator | Status | Depth |
|---|---|---|---|---|---|
| Mar 11, 2012 | Cox O-10-42095 | Spraberry (Trend Area) | XTO Energy Inc. | Producing | 11,550 |
Formation tops
As filed on W-2/G-1. Subsea from 2,765 ft elevation.Download CSV →
Perforations
Perforated and open-hole intervals.
| From | To | Type |
|---|---|---|
| 8,800 | 9,630 | Perforated |
| 8,800 | 11,440 | Perforated |
| 10,270 | 11,440 | Perforated |
Casing
Strings as reported, shallowest first.
| Casing in | Set at | Hole in | Cement |
|---|---|---|---|
| 13.375 | 450 | 17.5 | 350 S |
| 8.625 | 5,000 | 11 | 1,320 S |
| 5.5 | 11,540 | 7.875 | 1,200 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. The record date is the RRC's own date on the record, not the day the report was filed: 462,034 of the state's filings carry 1984-01-12. About these reports →
| Suffix | RRC record date | W-2 / G-1 date | Logs referenced |
|---|---|---|---|
| 00 | Oct 2, 2013 | Oct 26, 2012 | — |
| 00 | Jan 3, 2013 | Jul 27, 2011 | Yes |
Well logs
1 log loaded from the RRC's log index, the latest received May 26, 2014. Resistivity. These are the logs loaded into Petrora from the Railroad Commission's inventories, not necessarily every log run on the well. The RRC holds the files; each opens from its log search for the well. The kind is the RRC's description of the log; the interval is the one filed for it.
Open the RRC's log search for this well ↗| Logas described | Files | Intervalft, as filed | Datereceived | SizeMB |
|---|---|---|---|---|
| RESISTIVITYSpans Clear Fork, Spraberry, Dean, Wolfcamp, Strawn | TIFF | 4,970 to 11,532 | May 26, 2014run Mar 7, 2011 | 3.83 |
"Spans" is by this well's own filed formation tops: a formation runs from its top to the next deeper top filed, and the deepest runs to the bottom of the log. Depths are measured along the wellbore, so on a horizontal the lateral counts in the formation it was landed in.
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 42-317-36220 → W-2, G-1, plugging reports, as PDFs
- Completion packets for 42-317-36220 → scanned completion filings
The logs loaded for this well are under Well logs, with the RRC's log search for it. The University Lands library has no per-well link: then paste it into its search.
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/31736220, documented in the API reference.