TEXAS · WELLS · KARNES COUNTY · API 42-255-34739 · DISTRICT 02
Sienkiewicz Unit #4H
Karnes County · Sugarkane (Eagle Ford) field · Producing · Horizontal
Sienkiewicz Unit #4H (API 42-255-34739) is a horizontal well in Karnes County operated by Marathon Oil EF LLC, completed June 7, 2021 and listed as producing on the RRC schedule.
The RRC has issued one drilling permit (amended twice), issued September 4, 2015, permitted to 12,718 ft.
Completion filings report 10 formation tops, including Frio, Yegua, Queen City, Reklaw.
Its 2 leases have reported 1.29M barrels of oil and 4.68M mcf of gas since November 2012, last reporting volume in April 2026. The leases carry 7 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 LLCSep 4, 2015 |
- 12,718
- total depth, ft
- 3
- permits on file
- Sep 4, 2015
- last permit issued
- Jun 7, 2021
- completed
- 1.29M
- cumulative oil, bbl
- 4.68M
- cumulative gas, mcf
PRODUCTION FROM PDQ LEASE REPORTS · Dec 2012 THROUGH Apr 2026
Regulatory status · RRC wellbore file
- Schedule
- ON SCHEDULE
- Completed
- Jun 7, 2021
- Shut in
- —
- Plugged
- —
Operator's P-5 on the schedule: Active – Extension (X)
Surface location
28.845350, -97.900285 NAD27, as filed
28.845607, -97.900565 WGS84
Permit surface location from the RRC GIS record, referenced to NAD27 as the RRC files it; the WGS84 pair is the same point through NOAA's NADCON grid, and the map link uses it, in Karnes County.
Wells nearby
Every well with a location on file around this one, in any state, nearest first.
Loading the wells nearby…
Texas locations come from drilling permits, so most older Texas wells have none and are not listed.
Lease production
PDQ LEASE REPORTS · REPORTED THROUGH APR 2026
Texas reports oil by lease, not by well. These are the 2 leases this well is completed on; they carry 7 wells in total, so volumes are shared.Why →
| Lease | Field | Reporting operator | Wells | Oil, bbl | Gas, mcf | Reported |
|---|---|---|---|---|---|---|
| Sienkiewicz Unit G-2-290538 | Sugarkane (Eagle Ford) | Marathon Oil EF LLC | 1 | 225K | 805K | Jan 2021 – Apr 2026 |
| Sienkiewicz Unit O-2-10797 | Sugarkane (Eagle Ford) | Marathon Oil EF LLC | 6 | 1.06M | 3.88M | Nov 2012 – Feb 2026 |
Gas, mcf lease total
Last 12 months 48,633 · prior 12 83,956(-42%)
Oil, barrels lease total
Last 12 months 10,286 · prior 12 13,794(-25%)
Chain of custody
Every operator that reported production on this well's lease, in order.
- 1Marathon Oil EF LLCDec 2012 → Apr 2026
Permits
| Permit | Type | Operator | Received | Issued | Spud | Depth |
|---|---|---|---|---|---|---|
| 809801-97 | Drill | Marathon Oil EF LLC | Mar 29, 2021 | Sep 4, 2015 | Dec 31, 2015 | 19,000 |
| 809801-98 | Drill | Marathon Oil EF LLC | Oct 28, 2015 | Sep 4, 2015 | Dec 31, 2015 | 19,000 |
| 809801-99 | Drill | Marathon Oil EF LLC | Aug 26, 2015 | Sep 4, 2015 | Dec 31, 2015 | 19,000 |
Completions
| Completed | Lease | Field | Operator | Status | Depth |
|---|---|---|---|---|---|
| Jun 7, 2021 | Sienkiewicz Unit G-2-290538 | Sugarkane (Eagle Ford) | Marathon Oil EF LLC | Producing | 12,718 |
| Jan 24, 2016 | Sienkiewicz Unit O-2-10797 | Sugarkane (Eagle Ford) | Marathon Oil EF LLC | Not on Schedule | — |
Formation tops
As filed on W-2/G-1. Subsea from 372 ft elevation.Download CSV →
| Formation | MD ft | Subsea |
|---|---|---|
| FrioFRIO - DISPOSAL | 1,500 | -1,128 |
| YeguaYEGUA - DISPOSAL | 2,213 | -1,841 |
| Queen City | 4,477 | -4,105 |
| Reklaw | 4,833 | -4,461 |
| Carrizo | 5,407 | -5,035 |
| WilcoxWILCOX - DISPOSAL | 6,772 | -6,400 |
| Austin ChalkAUSTIN CHALK - H2S | 12,397 | -12,025 |
| Eagle FordEAGLE FORD - H2S | 12,565 | -12,193 |
| EdwardsEDWARDS - H2S | — | — |
| FrioFRIO - DISPOSAL | — | — |
| SligoSLIGO - H2S | — | — |
Perforations
Perforated and open-hole intervals.
| From | To | Type |
|---|---|---|
| 12,672 | 17,736 | Perforated |
Casing
Strings as reported, shallowest first.
| Casing in | Set at | Hole in | Cement |
|---|---|---|---|
| 9.625 | 5,948 | 12.25 | 1,835 S |
| 5.5 | 17,840 | 8.5 | 3,327 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 | Jul 19, 2021 | Jul 7, 2021 | — |
| 00 | Apr 14, 2021 | Feb 2, 2021 | — |
| 00 | Aug 18, 2016 | Jul 25, 2016 | Yes |
Well logs
1 log loaded from the RRC's log index, 1 of it with a digital LAS file, the latest received Jan 14, 2019. Gamma ray. 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 |
|---|---|---|---|---|
| Gamma RaySpans Wilcox, Austin Chalk, Eagle Ford | LAS + TIFF | 11,780 to 17,797 | Jan 14, 2019 | 0.36 + 10.6 |
"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 42-255-34739 → W-2, G-1, plugging reports, as PDFs
- Completion packets for 42-255-34739 → scanned completion filings
The logs loaded for this well are under Well logs, with the RRC's log search for it.
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.
Sienkiewicz Unit AC42-255-34738
0.0 KM · Marathon Oil EF LLC · Section with this well →
| Yegua | 2,213 | -1,843 |
| Queen City | 4,477 | -4,107 |
| Reklaw | 4,833 | -4,463 |
| Carrizo | 5,407 | -5,037 |
| Wilcox | 6,772 | -6,402 |
| Austin Chalk | 12,400 | -12,030 |
| Sligo | — | |
| Eagle Ford | — |
10 TOPS · FIRST 8
Sienkiewicz Unit AC42-255-34794
0.0 KM · Marathon Oil EF LLC · Section with this well →
| Yegua | 2,213 | -1,846 |
| Queen City | 4,477 | -4,110 |
| Reklaw | 4,833 | -4,466 |
| Carrizo | 5,407 | -5,040 |
| Wilcox | 6,772 | -6,405 |
| Austin Chalk | 12,399 | -12,032 |
| Eagle Ford | — | |
| Edwards | — |
10 TOPS · FIRST 8
Sienkiewicz Unit42-255-34795
0.0 KM · Marathon Oil EF LLC · Section with this well →
| Yegua | 2,213 | -1,847 |
| Queen City | 4,477 | -4,111 |
| Reklaw | 4,833 | -4,467 |
| Carrizo | 5,407 | -5,041 |
| Wilcox | 6,772 | -6,406 |
| Austin Chalk | 12,390 | -12,024 |
| Eagle Ford | 12,532 | -12,166 |
| Edwards | — |
10 TOPS · FIRST 8
Crew Unit A42-255-32148
0.4 KM · Burlington Resources O & G Co LP · Section with this well →
| Pecan Gap | 12,208 | -11,854 |
| Austin Chalk | 12,374 | -12,020 |
| Eagle Ford | 12,509 | -12,155 |
Crews Quad Ulw B42-255-38158
0.5 KM · Burlington Resources O & G Co LP · Section with this well →
| Yegua | 2,143 | -1,801 |
| Queen City | 4,127 | -3,785 |
| Reklaw | 4,530 | -4,188 |
| Carrizo | 4,731 | -4,389 |
| Wilcox | 5,438 | -5,096 |
| Austin Chalk | 12,383 | -12,041 |
| Eagle Ford | 12,522 | -12,180 |
| Sligo | — |
10 TOPS · FIRST 8
Crews Unit A42-255-38144
0.5 KM · Burlington Resources O & G Co LP · Section with this well →
| Yegua | 2,144 | -1,802 |
| Queen City | 4,127 | -3,785 |
| Reklaw | 4,518 | -4,176 |
| Carrizo | 4,731 | -4,389 |
| Wilcox | 5,433 | -5,091 |
| Austin Chalk | 12,350 | -12,008 |
| Eagle Ford | 12,481 | -12,139 |
| Edwards | — |
10 TOPS · FIRST 8
Kosub Unit42-255-38026
0.5 KM · Devon Energy Production Co, L.P. · Section with this well →
| Frio | 2,259 | -1,873 |
| Yegua | 3,257 | -2,871 |
| Queen City | 4,320 | -3,934 |
| Reklaw | 4,755 | -4,369 |
| Carrizo | 5,329 | -4,943 |
| Wilcox | 5,573 | -5,187 |
| Austin Chalk | 12,492 | -12,106 |
| Eagle Ford | 12,636 | -12,250 |
10 TOPS · FIRST 8
Kosub Unit42-255-38025
0.5 KM · Devon Energy Production Co, L.P. · Section with this well →
| Frio | 2,273 | -1,888 |
| Yegua | 3,272 | -2,887 |
| Queen City | 4,337 | -3,952 |
| Reklaw | 4,781 | -4,396 |
| Carrizo | 5,339 | -4,954 |
| Wilcox | 5,577 | -5,192 |
| Austin Chalk | 12,480 | -12,095 |
| Eagle Ford | 12,634 | -12,249 |
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/25534739, documented in the API reference.