TEXAS · WELLS · ATASCOSA COUNTY · HIERHOLZER RETZLOFF UNIT LEASE · API 42-013-34342 · DISTRICT 01
Hierholzer Retzloff Unit #1H
Atascosa County · Eagleville (Eagle Ford-1) field · Producing · Horizontal
- Fields on the latest permit · any of 2
- Eagleville (Eagle Ford-1) · Sugarkane (Eagle Ford)
- Not one formation; the well must be completed in one of them, and no target formation is stated.
Hierholzer Retzloff Unit #1H (API 42-013-34342) is a horizontal well in Atascosa County operated by Marathon Oil EF LLC, completed May 26, 2011 and listed as producing on the RRC schedule.
The RRC has issued one drilling permit, issued February 17, 2011, permitted to 10,543 ft.
It was permitted by Hilcorp Energy Company and has since transferred to Marathon Oil EF LLC on the wellbore schedule.
Completion filings report 4 formation tops, including Anacacho, Austin Chalk, Eagle Ford, Buda.
Its lease has reported 194K barrels of oil and 215K mcf of gas since May 2011, last reporting volume in December 2025.
Operator of record
Permitted by Hilcorp Energy Company; the EWA schedule now lists a different operator.
- 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 Dec 2025 |
| Latest permit | Hilcorp Energy CompanyFeb 17, 2011 |
The sources disagree, which usually means a transfer or a lease-level production filing by a different entity. Petrora goes with the schedule.
- 10,543
- total depth, ft
- 1
- permits on file
- Feb 17, 2011
- last permit issued
- May 26, 2011
- completed
- 194K
- cumulative oil, bbl
- 215K
- cumulative gas, mcf
PRODUCTION FROM PDQ LEASE REPORTS · JUN 2011 THROUGH DEC 2025
Regulatory status · RRC wellbore file
- Schedule
- ON SCHEDULE
- Completed
- May 26, 2011
- Shut in
- —
- Plugged
- —
Operator's P-5 on the schedule: Active – Extension (X)
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.
Wells nearby
Every well with a location on file around this well, in any state, nearest first.
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 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 |
|---|---|---|---|---|---|---|
| Hierholzer Retzloff Unit O-1-15621 | Eagleville (Eagle Ford-1) | Marathon Oil EF LLC | 1 | 194K | 215K | May 2011 – Dec 2025 |
Oil, barrels lease total
Last 12 months 3 · prior 12 5,074(-100%)
Gas, mcf lease total
Last 12 months 0 · prior 12 2,364(-100%)
Wells named Hierholzer Retzloff Unit
Marathon Oil EF LLC's other wells filed under this lease name in Atascosa County, newest permit first. The RRC gives a gas well its own lease number, so the name is what joins the wells of a unit.
Loading the lease's wellsChain of custody
Every operator that reported production on this well's lease, in order.
- 1Hilcorp Energy CompanyJun 2011 → Oct 2011
- 2Marathon Oil EF LLCNov 2011 → Dec 2025
Permits
| Permit | Type | Operator | Received | Issued | Spud | Depth |
|---|---|---|---|---|---|---|
| 710283-99 | Drill | Hilcorp Energy Company | Feb 14, 2011 | Feb 17, 2011 | Apr 16, 2011 | 13,500 |
Completions
| Completed | Lease | Field | Operator | Status | Depth |
|---|---|---|---|---|---|
| May 26, 2011 | Hierholzer Retzloff Unit O-1-15621 | Eagleville (Eagle Ford-1) | Marathon Oil EF LLC | Producing | 10,543 |
Formation tops
As filed on W-2/G-1. Subsea from 399 ft elevation.Download CSV →
| Formation | MD ft | Subsea |
|---|---|---|
| Anacacho | 10,338 | -9,939 |
| Austin Chalk | 10,459 | -10,060 |
| Eagle FordEAGLEFORD | 10,588 | -10,189 |
| Buda | 10,786 | -10,387 |
Perforations
Perforated and open-hole intervals.
| From | To | Type |
|---|---|---|
| 10,832 | 15,354 | Perforated |
Casing
Strings as reported, shallowest first.
| Casing in | Set at | Hole in | Cement |
|---|---|---|---|
| 10.75 | 5,116 | 13.5 | 1,615 S |
| 5.5 | 15,450 | 8.5 | 2,000 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 | Mar 15, 2012 | Oct 25, 2011 | 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 42-013-34342 → W-2, G-1, plugging reports, as PDFs
- Completion packets for 42-013-34342 → scanned completion filings
Log images filed since 2004 open from the RRC's log search for this well; none are loaded here for it.
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/01334342, documented in the API reference.