Reef Oil
Operator of record for 10 catalogued wells across 3 states. Every well below links to its full registry page.
Filed as: Reef Oil Co. · Reef Oil Corporation
At a glance
Reef Oil is the operator of record for 10 catalogued U.S. oil & gas wells in 3 states. None is listed as active, 10 (100%) are plugged & abandoned. Its largest concentration is in Illinois, with 6 wells (60% of its portfolio).
Wells operated
10
Active
0
Plugged
10
Orphaned
0
Portfolio by state
| State | Wells |
|---|---|
| Illinois | 6 |
| Montana | 3 |
| California | 1 |
Well mix
- Oil wells
- 6
- Gas wells
- 0
- Shut-in
- 0
- Active share
- 0%
Is this your company?
Claim Reef Oil to keep this portfolio accurate — verified operators can correct well statuses and add plugging documentation.
Claim your operator profileWhere does Reef Oil operate?
Reef Oil's catalogued wells are spread across 3 states: Illinois (6), Montana (3) and California (1). Its 3 Montana wells are 0.0% of the 42,011 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 Reef Oil’s wells are active, plugged or orphaned?
0% of Reef Oil's catalogued wells are active, 29 percentage points below the national share of 29%. 100% are plugged & abandoned, against 47% nationally. None of the wells filed under this name is flagged as orphaned.
What kinds of wells does Reef Oil operate?
By product class, 6 (60%) are oil wells and 0 (0%) gas wells; nationally the shares are 43% and 17%. The deepest of its wells with a published depth is Irelan-Robinson 1 in Sheridan, MT at 9,000 ft. The wells listed below sit in Sheridan (MT), Daniels (MT), Richland (IL), Coles (IL) and San Mateo (CA). State filings spell the name 2 ways; WellCensus merges exact-normalized spellings only, so subsidiaries and affiliates keep their own pages.
Notable wells operated by Reef Oil
| Well | API # / state ID | Status | Type | Location | Operator | Depth |
|---|---|---|---|---|---|---|
| Irelan-Robinson 1 | 25-091-21605 | Plugged & abandoned | Other type | Sheridan, MT | Reef Oil Corporation | 9,000 ft |
| Wilcoxon #1 | 25-019-21088 | Plugged & abandoned | Oil | Daniels, MT | Reef Oil Corporation | 7,410 ft |
| Kamm-Ireland-Robinson 1 | 25-091-21644 | Plugged & abandoned | Other type | Sheridan, MT | Reef Oil Corporation | 6,500 ft |
| Sims F M 3 | 12-159-02843 | Plugged & abandoned | Oil | Richland, IL | Reef Oil Co. | 3,635 ft |
| Buerster 1 | 12-159-02960 | Plugged & abandoned | Oil | Richland, IL | Reef Oil Co. | 3,620 ft |
| Perring, Jw 1 | 12-159-02885 | Plugged & abandoned | Oil | Richland, IL | Reef Oil Co. | 3,604 ft |
| Schnell D 1 | 12-159-02826 | Plugged & abandoned | Oil | Richland, IL | Reef Oil Co. | 3,520 ft |
| Neff-Miller-Crum Comm. 3 | 12-029-00593 | Plugged & abandoned | Oil | Coles, IL | Reef Oil Co. | 1,856 ft |
| Whitley, Joseph Com. 1 | 12-029-00634 | Plugged & abandoned | Other type | Coles, IL | Reef Oil Co. | 1,851 ft |
| Souza 1 | 04-081-00119 | Plugged & abandoned | Other type | San Mateo, CA | Reef Oil Co. | — |
Deepest first where depth is published. See all 10 wells →
Frequently asked questions
How many wells does Reef Oil operate?
Reef Oil is the operator of record for 10 catalogued oil & gas wells, with the largest concentration in Illinois (6). Only wells in states WellCensus has ingested are counted.
How many of Reef Oil's wells are still active?
0 of Reef Oil's catalogued wells are active; 10 are plugged & abandoned.
In which states does Reef Oil operate wells?
Reef Oil is the operator of record for wells in Illinois (6), Montana (3) and California (1).
Does Reef Oil operate mostly oil or gas wells?
6 of Reef Oil's catalogued wells are oil wells and 0 are gas wells; the rest are injection, service or unclassified wells.
What is Reef Oil's deepest well?
Among wells with a published depth, Irelan-Robinson 1 in Sheridan, MT is the deepest at 9,000 ft.
Where Reef Oil'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, “Reef Oil — well portfolio”, https://wellcensus.com/operators/reef-oil-14078 (data as of October 10, 2026).
Dataset updated . Operator portfolios are resolved from raw state registry filings (exact-normalized names; subsidiaries stay separate).