O Brien Sill
Operator of record for 23 catalogued wells across 1 state. Every well below links to its full registry page.
At a glance
O Brien Sill is the operator of record for 23 catalogued U.S. oil & gas wells in 1 state. 9 (39%) are active, 13 (57%) plugged & abandoned. Its largest concentration is in California, with 23 wells (100% of its portfolio).
Wells operated
23
Active
9
Plugged
13
Orphaned
0
Portfolio by state
| State | Wells |
|---|---|
| California | 23 |
Well mix
- Oil wells
- 22
- Gas wells
- 0
- Shut-in
- 1
- Active share
- 39%
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Claim your operator profileWhere does O Brien Sill operate?
O Brien Sill's catalogued wells are spread across 1 state: California (23). Its 23 California wells are 0.0% of the 242,471 catalogued in that state — its largest share of any state. Counts cover only states whose registries WellCensus has ingested with operator names; wells in Nebraska and Texas (location indexes) and in states without a registry ingest are not yet attributed to any operator.
How many of O Brien Sill’s wells are active, plugged or orphaned?
39% of O Brien Sill's catalogued wells are active, 10 percentage points above the national share of 29%. 57% are plugged & abandoned, against 47% nationally. 1 wells (4%) are shut-in — unplugged but idle. None of the wells filed under this name is flagged as orphaned.
What kinds of wells does O Brien Sill operate?
By product class, 22 (96%) are oil wells and 0 (0%) gas wells; nationally the shares are 43% and 17%.
Notable wells operated by O Brien Sill
| Well | API # / state ID | Status | Type | Location | Operator | Depth |
|---|---|---|---|---|---|---|
| Lease by O'Brien-Sill 1 | 04-029-38930 | Shut-in | Other type | Kern, CA | O'Brien-Sill | — |
| O'Brien 6 | 04-029-38942 | Plugged & abandoned | Oil | Kern, CA | O'Brien-Sill | — |
| O'Brien 10 | 04-029-38946 | Active | Oil | Kern, CA | O'Brien-Sill | — |
| Hart-Dearin 1 | 04-029-38935 | Plugged & abandoned | Oil | Kern, CA | O'Brien-Sill | — |
| O'Brien 2 | 04-029-38938 | Active | Oil | Kern, CA | O'Brien-Sill | — |
| Hart-Dearin 3 | 04-029-63948 | Active | Oil | Kern, CA | O'Brien-Sill | — |
| O'Brien 8 | 04-029-38944 | Active | Oil | Kern, CA | O'Brien-Sill | — |
| Hart-Dearin 2 | 04-029-38936 | Active | Oil | Kern, CA | O'Brien-Sill | — |
| O'Brien 3 | 04-029-38939 | Plugged & abandoned | Oil | Kern, CA | O'Brien-Sill | — |
| O'Brien 5 | 04-029-38941 | Plugged & abandoned | Oil | Kern, CA | O'Brien-Sill | — |
| O'Brien 4 | 04-029-38940 | Plugged & abandoned | Oil | Kern, CA | O'Brien-Sill | — |
| O'Brien 7 | 04-029-38943 | Active | Oil | Kern, CA | O'Brien-Sill | — |
Deepest first where depth is published. See all 23 wells →
Frequently asked questions
How many wells does O Brien Sill operate?
O Brien Sill is the operator of record for 23 catalogued oil & gas wells, with the largest concentration in California (23). Only wells in states WellCensus has ingested are counted.
How many of O Brien Sill's wells are still active?
9 of O Brien Sill's catalogued wells are active; 13 are plugged & abandoned.
In which states does O Brien Sill operate wells?
O Brien Sill is the operator of record for wells in California (23).
Does O Brien Sill operate mostly oil or gas wells?
22 of O Brien Sill's catalogued wells are oil wells and 0 are gas wells; the rest are injection, service or unclassified wells.
Where O Brien Sill's wells are
About this data
Source: State oil & gas regulator registries (operator of record as filed, exact-normalized across states) plus the USGS United States Documented Orphaned Well Database (2026), as published October 10, 2026 — WellCensus refreshes it monthly. See the methodology for how records are matched, cleaned and scored.
Cite as: WellCensus, “O Brien Sill — well portfolio”, https://wellcensus.com/operators/o-brien-sill-8346 (data as of October 10, 2026).
Dataset updated . Operator portfolios are resolved from raw state registry filings (exact-normalized names; subsidiaries stay separate).