WELL · 42-255-36943 · DISTRICT 2
Challenger Unit C-B SA #1H
Karnes County · Eagleville (Eagle Ford-2) field · Producing · Horizontal
Challenger Unit C-B SA #1H (API 42-255-36943) is a horizontal well in Karnes County operated by Marathon Oil EF LLC, completed March 26, 2021 and listed as producing on the RRC schedule.
The RRC has issued one drilling permit, issued May 14, 2020, permitted to 23,000 ft.
Completion filings report 10 formation tops, including Yegua, Queen City, Reklaw, Carrizo.
Its lease has reported 283K barrels of oil and 432K mcf of gas since August 2020, last reporting in July 2026.
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 LLCMay 14, 2020 |
- 23,000
- total depth, ft
- 1
- permits on file
- May 14, 2020
- last permit issued
- Mar 26, 2021
- completed
- 283K
- cumulative oil, bbl
- 432K
- cumulative gas, mcf
PRODUCTION FROM PDQ LEASE REPORTS · Aug 2020 THROUGH Jul 2026
Regulatory status · RRC wellbore file
- Schedule
- ON SCHEDULE
- Completed
- Mar 26, 2021
- Shut in
- —
- Plugged
- —
Operator's P-5 on the schedule: Active (A)
Surface location
28.904880, -97.997001
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; this well is the only one on it.Why →
| Lease | Field | Reporting operator | Wells | Oil, bbl | Gas, mcf | Reported |
|---|---|---|---|---|---|---|
| Challenger Unit C-B SA O-2-12092 | Eagleville (Eagle Ford-2) | Marathon Oil EF LLC | 1 | 283K | 432K | Aug 2020 – Jul 2026 |
Oil, barrels lease total
Last 12 months 23,840 · prior 12 29,163(-18%)
Gas, mcf lease total
Last 12 months 39,343 · prior 12 49,798(-21%)
Chain of custody
Every operator that reported production on this well's lease, in order.
- 1Marathon Oil EF LLCJan 2021 → Apr 2026
Permits
| Permit | Type | Operator | Received | Issued | Spud | Depth |
|---|---|---|---|---|---|---|
| 863582-99 | Drill | Marathon Oil EF LLC | May 8, 2020 | May 14, 2020 | Aug 22, 2020 | 23,000 |
Completions
| Completed | Lease | Field | Operator | Status | Depth |
|---|---|---|---|---|---|
| — | — O-2-12092 | — | — | — | — |
Formation tops
As filed on W-2/G-1. Subsea from 345 ft elevation.Download CSV →
| Formation | MD ft | Subsea |
|---|---|---|
| YeguaYEGUA - DISPOSAL | 1,419 | -1,074 |
| Queen City | 3,279 | -2,934 |
| Reklaw | 3,589 | -3,244 |
| Carrizo | 4,304 | -3,959 |
| WilcoxWILCOX - DISPOSAL | 5,491 | -5,146 |
| Austin ChalkAUSTIN CHALK - H2S | 10,603 | -10,258 |
| Eagle FordEAGLE FORD - H2S | 10,848 | -10,503 |
| EdwardsEDWARDS - H2S | — | — |
| FrioFRIO - DISPOSAL | — | — |
| SligoSLIGO - H2S | — | — |
Perforations
Perforated and open-hole intervals.
| From | To | Type |
|---|---|---|
| 11,289 | 16,553 | Perforated |
Casing
Strings as reported, shallowest first.
| Casing in | Set at | Hole in | Cement |
|---|---|---|---|
| 9.625 | 5,412 | 12.25 | 1,544 S |
| 5.5 | 16,553 | 8.75 | 2,577 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 | May 11, 2021 | Apr 20, 2021 | Yes |
| 00 | Mar 24, 2021 | Feb 25, 2021 | Yes |
| 00 | Nov 19, 2020 | Nov 11, 2020 | 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 42-255-36943 → W-2, G-1, plugging reports, as PDFs
- Completion packets for 42-255-36943 → 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.
Medina-Hoffman Unit42-255-36941
0.0 KM · Marathon Oil EF LLC · Section with this well →
| Yegua | 1,419 | -1,074 |
| Queen City | 3,279 | -2,934 |
| Reklaw | 3,589 | -3,244 |
| Carrizo | 4,304 | -3,959 |
| Wilcox | 5,491 | -5,146 |
| Austin Chalk | 10,589 | -10,244 |
| Eagle Ford | 10,849 | -10,504 |
| Edwards | — |
10 TOPS · FIRST 8
Mohr-Hons Medina-Hoffman SA42-255-36942
0.0 KM · Marathon Oil EF LLC · Section with this well →
| Yegua | 1,423 | -1,078 |
| Queen City | 3,283 | -2,938 |
| Reklaw | 3,593 | -3,248 |
| Carrizo | 4,308 | -3,963 |
| Wilcox | 5,495 | -5,150 |
| Austin Chalk | 10,551 | -10,206 |
| Eagle Ford | 10,813 | -10,468 |
| Edwards | — |
10 TOPS · FIRST 8
Medina-Hoffman Unit42-255-36422
0.5 KM · Marathon Oil EF LLC · Section with this well →
| Queen City | 2,897 | -2,548 |
| Reklaw | 3,207 | -2,858 |
| Carrizo | 3,922 | -3,573 |
| Wilcox | 5,109 | -4,760 |
| Austin Chalk | 10,613 | -10,264 |
| Eagle Ford | 10,879 | -10,530 |
| Frio | — | |
| Edwards | — |
10 TOPS · FIRST 8
Medina-Hoffman Unit42-255-36419
0.5 KM · Marathon Oil EF LLC · Section with this well →
| Queen City | 2,897 | -2,548 |
| Reklaw | 3,207 | -2,858 |
| Carrizo | 3,922 | -3,573 |
| Wilcox | 5,109 | -4,760 |
| Austin Chalk | 10,617 | -10,268 |
| Eagle Ford | 10,877 | -10,528 |
| Yegua | — | |
| Edwards | — |
10 TOPS · FIRST 8
Medina-Hoffman Unit42-255-36420
0.5 KM · Marathon Oil EF LLC · Section with this well →
| Queen City | 2,897 | -2,548 |
| Reklaw | 3,207 | -2,858 |
| Carrizo | 3,922 | -3,573 |
| Wilcox | 5,109 | -4,760 |
| Austin Chalk | 10,625 | -10,276 |
| Eagle Ford | 10,884 | -10,535 |
| Edwards | — | |
| Yegua | — |
10 TOPS · FIRST 8
Medina-Hoffman Unit42-255-36421
0.5 KM · Marathon Oil EF LLC · Section with this well →
| Queen City | 2,897 | -2,548 |
| Reklaw | 3,207 | -2,858 |
| Carrizo | 3,922 | -3,573 |
| Wilcox | 5,109 | -4,760 |
| Austin Chalk | 10,633 | -10,284 |
| Eagle Ford | 10,886 | -10,537 |
| Yegua | — | |
| Sligo | — |
10 TOPS · FIRST 8
Medina-Hoffman Medina-Trial SA42-255-36423
0.5 KM · Marathon Oil EF LLC · Section with this well →
| Queen City | 2,897 | -2,548 |
| Reklaw | 3,207 | -2,858 |
| Carrizo | 3,922 | -3,573 |
| Wilcox | 5,109 | -4,760 |
| Austin Chalk | 10,659 | -10,310 |
| Eagle Ford | 10,912 | -10,563 |
| Yegua | — | |
| Sligo | — |
10 TOPS · FIRST 8
Challenger Unit C AC42-255-36039
0.6 KM · Marathon Oil EF LLC · Section with this well →
| Yegua | 1,294 | -952 |
| Queen City | 3,154 | -2,812 |
| Reklaw | 3,464 | -3,122 |
| Carrizo | 4,179 | -3,837 |
| Wilcox | 5,366 | -5,024 |
| Austin Chalk | 10,518 | -10,176 |
| Frio | — | |
| Edwards | — |
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/25536943, documented in the API reference.