RRC field 80280500 · District 02
San Marcos (Austin Chalk)
The San Marcos (Austin Chalk) field reported 3,625 mcf of gas and 51 barrels of oil in the last 12 months.
Field dossier
3,625mcf gas, last 12 months−77% vs prior year
- Producing leases
- 1
- Operators
- 1
- Counties
- 1
- Biggest operator
- Marathon Oil Ef LLC
Own minerals in this field?
Where the field sits
This county
1 county
- Oil, last 12 months
- 51 bbl
- Data through
- Jul 2026
Five years of output in San Marcos (Austin Chalk)
Gas output in the San Marcos (Austin Chalk) field fell 77% over the last 12 months
3,625 mcf through Jul 2026, against 15.6k mcf a year earlier. Peak Mar 2025: 4,448 mcf.
Oil output in the San Marcos (Austin Chalk) field fell 80% over the last 12 months
51 bbl through Jul 2026, against 261 bbl a year earlier. Peak Apr 2022: 342 bbl.
SourceTexas Railroad Commission Production Data Query, field 80280500, through Jul 2026, file dated Sep 18, 2026.
Leases in the San Marcos (Austin Chalk) field
Under each volume: change on the year before.
3,625mcf gas−77%
Showing 1 of 1.
SourceTexas Railroad Commission Production Data Query.
Recent drilling permits in the San Marcos (Austin Chalk) field
No recent permits.