WELL · 42-391-31278 · DISTRICT 2
O'Brien, J.M. #312
Refugio County · Vertical
O'Brien, J.M. #312 (API 42-391-31278) is a disposal or injection well in Refugio County operated by Cambrian Management, Ltd. under an active UIC permit.
The RRC has issued 2 drilling permits between 1978 and 2010, permitted to 4,900 ft.
Its 3 leases have reported 495K barrels of oil and 351K mcf of gas since January 1993, last reporting in July 2026. The leases carry 17 wells, so these are lease totals, not this well alone.
It holds an active disposal or injection permit.
Operator of record
- Based in
- McCaulley, TX
- P-5 status
- Active (A)
- P-5 last filed
- Jul 16, 2026
- Permits on file
- 107
- Phone
- (432) 664-7052
SOURCE · RRC EWA WELLBORE SCHEDULE
What each RRC source says
| Wellbore schedule | none |
| Production reports | Dorchester Operating Company LLCthrough Apr 2026 |
| Latest permit | Cambrian Management, Ltd.Feb 25, 2010 |
- 4,900
- total depth, ft
- 2
- permits on file
- Feb 25, 2010
- last permit issued
- —
- completed
- 495K
- cumulative oil, bbl
- 351K
- cumulative gas, mcf
PRODUCTION FROM PDQ LEASE REPORTS · Jan 1993 THROUGH Jul 2026
Regulatory status · RRC wellbore file
- Schedule
- OFF SCHEDULE
- Completed
- —
- Shut in
- —
- Plugged
- —
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 3 leases this well is completed on; they carry 17 wells in total, so volumes are shared.Why →
| Lease | Field | Reporting operator | Wells | Oil, bbl | Gas, mcf | Reported |
|---|---|---|---|---|---|---|
| O'Brien, J.M. G-2-256500 | Greta (C-2) | Dorchester Operating Company LLC | 1 | 0 | 0 | Aug 2008 – Jul 2026 |
| O'Brien, J. M. O-2-3981 | Greta (4400) | Dorchester Operating Company LLC | 10 | 380K | 252K | Jan 1993 – Jul 2026 |
| Obrien, J. M. O-2-3997 | Greta (4400) | Primrose Operating Company | 6 | 116K | 98.9K | Jan 1993 – Oct 2005 |
Oil, barrels lease total
Last 12 months 4,832 · prior 12 5,674(-15%)
Gas, mcf lease total
Last 12 months 1,988 · prior 12 2,743(-28%)
Chain of custody
Every operator that reported production on this well's lease, in order.
- 1Dewbre Petroleum CorporationJan 1993 → Oct 2002
- 2Exxon Corp.Jan 1993 → Mar 2000
- 3Exxon Mobil CorporationApr 2000 → Oct 2001
- 4Primrose Operating CompanyNov 2001 → Mar 2007
- 5Cambrian Management LtdApr 2007 → Sep 2007
- 6Cambrian Management, Ltd.Oct 2007 → Oct 2010
- 7Acock/Anaqua Operating Co., LPNov 2010 → Nov 2020
- 8Dorchester Operating Company LLCDec 2020 → Apr 2026
Permits
| Permit | Type | Operator | Received | Issued | Spud | Depth |
|---|---|---|---|---|---|---|
| 691499-99 | Recompletion | Cambrian Management, Ltd. | Feb 18, 2010 | Feb 25, 2010 | Apr 14, 2008 | 4,503 |
| 41532-99 | Drill | Exxon Corp. | Oct 10, 1978 | Oct 10, 1978 | Dec 1, 1978 | 4,900 |
Completions
| Completed | Lease | Field | Operator | Status | Depth |
|---|---|---|---|---|---|
| — | — G-2-256500 | — | — | — | — |
| — | — O-2-3981 | — | — | — | — |
| — | — O-2-3981 | — | — | — | — |
| — | — O-2-3997 | — | — | — | — |
Perforations
Perforated and open-hole intervals.
| From | To | Type |
|---|---|---|
| 2,695 | 2,720 | Perforated |
| 2,750 | 2,760 | Perforated |
| 2,800 | 2,840 | Perforated |
| 2,995 | 3,025 | Perforated |
| 3,390 | 3,394 | Open hole |
| 4,364 | 4,368 | Perforated |
Casing
Strings as reported, shallowest first.
| Casing in | Set at | Hole in | Cement |
|---|---|---|---|
| 13.375 | 342 | 17.5 | 350 S |
| 8.625 | 1,339 | 12.5 | 550 S |
| 2.875 | 3,852 | — | — |
| 5.5 | 4,486 | 7.875 | 500 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 9, 2010 | Dec 10, 2008 | Yes |
| 00 | Jul 12, 2010 | — | — |
| 00 | Sep 14, 2005 | Jan 11, 1979 | — |
| 00 | Aug 12, 2005 | Jan 11, 1979 | — |
| 00 | Jan 12, 1984 | Jan 11, 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 42-391-31278 → W-2, G-1, plugging reports, as PDFs
- Completion packets for 42-391-31278 → 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
- 220K
- bbl, all reported
- Nov 2025
- reported through
| UIC | Kind | Status | Permitted bbl/d | Max psi | Zone ft |
|---|---|---|---|---|---|
| 000096033 | H-1 Injection | Active | 10,000 | 1,200 | 2,400–3,650 |
MONTHLY INJECTED, BBL · H-10 · LAST 24 REPORTED MONTHS
Last 12 months 0 · prior 12 0
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/39131278, documented in the API reference.