LEASES · O-2-10797 · OIL · DISTRICT 02
Sienkiewicz Unit
ReportingMarathon Oil EF LLC · Karnes County · Sugarkane (Eagle Ford) field
Sienkiewicz Unit is an RRC oil lease (O-2-10797) in Karnes County operated by Marathon Oil EF LLC, with 6 wells completed on it.
It has reported 1.06M barrels of oil and 3.88M mcf of gas since December 2012, last reporting volume in February 2026 (statewide data runs through April 2026).
It reported 10.3K barrels of oil in the 12 months through April 2026, down 25% on the year before; the lease peaked at 56.5K barrels in May 2015.
- 1.06M
- bbl oil, all reported
- 3.88M
- mcf gas incl. casinghead
- 10.3K
- bbl oil, 12 months through Apr 2026
- -25%
- vs the 12 before
- 6
- wells completed on it
- 56.5K
- peak month, bbl (May 2015)
PDQ LEASE REPORTS · FIRST DEC 2012 · LAST VOLUME FEB 2026 · STATEWIDE DATA THROUGH APR 2026
Oil by month
Barrels reported on Form PR for the whole lease. The latest months are revised upward as late reports arrive.
12 months through Apr 2026 10,286 · prior 12 13,794(-25%)
Gas by month
Gas-well gas plus casinghead gas, mcf. On an oil lease all gas is reported as casinghead. The latest months are revised upward as late reports arrive.
12 months through Apr 2026 29,803 · prior 12 49,963(-40%)
Decline curve
A MODEL FITTED TO THE REPORTS, NOT A REPORT
An Arps exponential curve fitted to the 118 reporting months of oil since the peak in May 2016. The dashed line below is that curve, drawn over the months it was fitted to and then 24 months past the last report; where it parts from the columns is where the model stops describing the lease. It describes the trend of past reports. It does not know about recompletions, shut-ins, or new wells, and it is shown only when the lease reported within the last year and the curve explains most of the history.
- 24%
- first-year decline from the peak (nominal Di 27%)
- 0.0
- b factor (exponential)
- 0.74
- fit R²
- 25.3K
- bbl remaining on the curve, to 1 per month
Oil, barrels reported months since the peak, with the fitted curve and its projection
Last 12 months 10,286 · prior 12 13,794(-25%)
Fitted exponential curve from the May 2016 peak, dashed 24 months past the last report
| Projected month | Oct 2026 | Apr 2027 | Oct 2027 | Apr 2028 |
|---|---|---|---|---|
| On the curve, bbl per month | 499 | 436 | 381 | 333 |
Quoting a projected figure as if it were reported would be wrong; the reported figures are the ones in the charts and the table view. How production is reported →
Who reported it
Each run of months one operator filed the production report, oldest first.
- Marathon Oil EF LLCNov 2012 → Jul 2026 · 165 mo
Wells on the lease
FROM COMPLETION REPORTS · PRODUCTION ABOVE IS THEIR TOTAL
6
wells completed on the lease
- Producing
- 4
- Not on Schedule
- 2
Operates them now
About this data
Monthly oil, gas, and casinghead from the RRC PDQ production dump, which lags the reporting month by two to three months; figures shown through Apr 2026. Wells from completion reports; operator runs from who filed each month's report.
Developers: this page as JSON is GET /v1/data/leases/tx/o-2-10797, documented in the API reference.