WELL · 42-255-37159 · DISTRICT 2
Challenger AC Unit A #4H
Karnes County · Sugarkane (Austin Chalk) field · Producing · Horizontal
Challenger AC Unit A #4H (API 42-255-37159) is a horizontal well in Karnes County operated by Marathon Oil EF LLC, completed October 27, 2021 and listed as producing on the RRC schedule.
The RRC has issued one drilling permit, issued March 23, 2021, permitted to 22,000 ft.
Completion filings report 10 formation tops, including Queen City, Reklaw, Carrizo, Wilcox.
Its lease has reported 549K barrels of oil and 1.45M mcf of gas since June 2021, last reporting in July 2026. The lease carries 2 wells, so these are lease totals, not this well alone.
Operator of record
- Based in
- Houston, TX
- P-5 status
- Active (A)
- P-5 last filed
- Sep 26, 2025
- Permits on file
- 3,191
- Phone
- (832) 486-2737
SOURCE · RRC EWA WELLBORE SCHEDULE
What each RRC source says
| Wellbore schedule | Marathon Oil EF LLC |
| Production reports | Marathon Oil EF LLCthrough Apr 2026 |
| Latest permit | Marathon Oil EF LLCMar 23, 2021 |
- 22,000
- total depth, ft
- 1
- permits on file
- Mar 23, 2021
- last permit issued
- Oct 27, 2021
- completed
- 549K
- cumulative oil, bbl
- 1.45M
- cumulative gas, mcf
PRODUCTION FROM PDQ LEASE REPORTS · Jun 2021 THROUGH Jul 2026
Regulatory status · RRC wellbore file
- Schedule
- ON SCHEDULE
- Completed
- Oct 27, 2021
- Shut in
- —
- Plugged
- —
Operator's P-5 on the schedule: Active (A)
Surface location
28.921333, -97.983874
Permit surface location from the RRC GIS record, in Karnes 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 2 wells in total, so volumes are shared.Why →
| Lease | Field | Reporting operator | Wells | Oil, bbl | Gas, mcf | Reported |
|---|---|---|---|---|---|---|
| Challenger AC Unit A O-2-12193 | Sugarkane (Austin Chalk) | Marathon Oil EF LLC | 2 | 549K | 1.45M | Jun 2021 – Jul 2026 |
Oil, barrels lease total
Last 12 months 37,886 · prior 12 41,635(-9%)
Gas, mcf lease total
Last 12 months 123,274 · prior 12 148,971(-17%)
Chain of custody
Every operator that reported production on this well's lease, in order.
- 1Marathon Oil EF LLCAug 2021 → Apr 2026
Permits
| Permit | Type | Operator | Received | Issued | Spud | Depth |
|---|---|---|---|---|---|---|
| 868392-99 | Drill | Marathon Oil EF LLC | Mar 15, 2021 | Mar 23, 2021 | Jun 1, 2021 | 22,000 |
Completions
| Completed | Lease | Field | Operator | Status | Depth |
|---|---|---|---|---|---|
| — | — O-2-12193 | — | — | — | — |
Formation tops
As filed on W-2/G-1. Subsea from 305 ft elevation.Download CSV →
| Formation | MD ft | Subsea |
|---|---|---|
| Queen City | 2,706 | -2,401 |
| Reklaw | 3,630 | -3,325 |
| Carrizo | 4,060 | -3,755 |
| WilcoxWILCOX - DISPOSAL | 4,135 | -3,830 |
| Austin ChalkAUSTIN CHALK - H2S | 10,539 | -10,234 |
| Eagle FordEAGLE FORD - H2S | — | — |
| EdwardsEDWARDS - H2S | — | — |
| FrioFRIO - DISPOSAL | — | — |
| SligoSLIGO - H2S | — | — |
| YeguaYEGUA - DISPOSAL | — | — |
Perforations
Perforated and open-hole intervals.
| From | To | Type |
|---|---|---|
| 10,838 | 16,494 | Perforated |
Casing
Strings as reported, shallowest first.
| Casing in | Set at | Hole in | Cement |
|---|---|---|---|
| 9.625 | 5,241 | 12.25 | 1,518 S |
| 5.5 | 16,494 | 8.75 | 2,918 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 | Dec 10, 2021 | Nov 30, 2021 | Yes |
| 00 | Dec 8, 2021 | Sep 24, 2021 | Yes |
| 00 | Aug 13, 2021 | Jul 9, 2021 | Yes |
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 42-255-37159 → W-2, G-1, plugging reports, as PDFs
- Completion packets for 42-255-37159 → 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.
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 neighbors, subsea-aligned so they line up regardless of surface terrain.
Challenger Unit B-a AC SA42-255-37160
0.0 KM · Marathon Oil EF LLC · Section with this well →
| Queen City | 2,706 | -2,400 |
| Reklaw | 3,630 | -3,324 |
| Carrizo | 4,060 | -3,754 |
| Wilcox | 4,135 | -3,829 |
| Austin Chalk | 10,472 | -10,166 |
| Yegua | — | |
| Eagle Ford | — | |
| Edwards | — |
10 TOPS · FIRST 8
Challenger AC Unit A42-255-37158
0.0 KM · Marathon Oil EF LLC · Section with this well →
| Queen City | 2,706 | -2,401 |
| Reklaw | 3,630 | -3,325 |
| Carrizo | 4,060 | -3,755 |
| Wilcox | 4,135 | -3,830 |
| Austin Chalk | 10,513 | -10,208 |
| Yegua | — | |
| Sligo | — | |
| Frio | — |
10 TOPS · FIRST 8
Berdie Unit42-255-37261
0.3 KM · Validus NRG Aquilas Assetco LLC · Section with this well →
| Yegua | 1,399 | -1,095 |
| Queen City | 2,603 | -2,299 |
| Reklaw | 3,392 | -3,088 |
| Carrizo | 4,104 | -3,800 |
| Wilcox | 4,505 | -4,201 |
| Austin Chalk | 10,498 | -10,194 |
| Sligo | — | |
| Edwards | — |
10 TOPS · FIRST 8
Berdie Unit42-255-37259
0.3 KM · Validus NRG Aquilas Assetco LLC · Section with this well →
| Yegua | 1,358 | -1,017 |
| Queen City | 2,576 | -2,235 |
| Reklaw | 3,366 | -3,025 |
| Carrizo | 4,058 | -3,717 |
| Wilcox | 4,468 | -4,127 |
| Austin Chalk | 10,457 | -10,116 |
| Eagle Ford | 10,700 | -10,359 |
| Sligo | — |
10 TOPS · FIRST 8
Berdie Unit42-255-37260
0.3 KM · Validus NRG Aquilas Assetco LLC · Section with this well →
| Yegua | 1,470 | -1,166 |
| Queen City | 2,685 | -2,381 |
| Reklaw | 3,478 | -3,174 |
| Carrizo | 4,170 | -3,866 |
| Wilcox | 4,595 | -4,291 |
| Austin Chalk | 10,409 | -10,105 |
| Frio | — | |
| Edwards | — |
10 TOPS · FIRST 8
Berdie Unit42-255-36210
0.8 KM · Encana Oil & Gas(usa) Inc. · Section with this well →
| Yegua | 1,245 | -916 |
| Queen City | 3,156 | -2,827 |
| Reklaw | 3,468 | -3,139 |
| Carrizo | 4,047 | -3,718 |
| Wilcox | 4,933 | -4,604 |
| Austin Chalk | 10,559 | -10,230 |
| Eagle Ford | 10,707 | -10,378 |
| Edwards | — |
10 TOPS · FIRST 8
Berdie Unit42-255-36209
0.8 KM · Encana Oil & Gas(usa) Inc. · Section with this well →
| Yegua | 1,245 | -916 |
| Queen City | 3,156 | -2,827 |
| Reklaw | 3,468 | -3,139 |
| Carrizo | 4,047 | -3,718 |
| Wilcox | 5,933 | -5,604 |
| Austin Chalk | 10,548 | -10,219 |
| Eagle Ford | 10,704 | -10,375 |
| Frio | — |
10 TOPS · FIRST 8
Berdie Unit42-255-36208
0.8 KM · Encana Oil & Gas(usa) Inc. · Section with this well →
| Yegua | 1,245 | -916 |
| Queen City | 3,156 | -2,827 |
| Reklaw | 3,468 | -3,139 |
| Carrizo | 4,047 | -3,718 |
| Wilcox | 5,933 | -5,604 |
| Austin Chalk | 10,558 | -10,229 |
| Eagle Ford | 10,706 | -10,377 |
| Sligo | — |
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/25537159, documented in the API reference.