Annex Oil
Operator of record for 18 catalogued wells across 1 state. Every well below links to its full registry page.
At a glance
Annex Oil is the operator of record for 18 catalogued U.S. oil & gas wells in 1 state. None is listed as active, 14 (78%) are plugged & abandoned. Its largest concentration is in Michigan, with 18 wells (100% of its portfolio).
Wells operated
18
Active
0
Plugged
14
Orphaned
0
Portfolio by state
| State | Wells |
|---|---|
| Michigan | 18 |
Well mix
- Oil wells
- 0
- Gas wells
- 0
- Shut-in
- 0
- Active share
- 0%
Is this your company?
Claim Annex Oil to keep this portfolio accurate — verified operators can correct well statuses and add plugging documentation.
Claim your operator profileWhere does Annex Oil operate?
Annex Oil's catalogued wells are spread across 1 state: Michigan (18). Its 18 Michigan wells are 0.0% of the 85,673 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 Annex Oil’s wells are active, plugged or orphaned?
0% of Annex Oil's catalogued wells are active, 29 percentage points below the national share of 29%. 78% are plugged & abandoned, against 47% nationally. None of the wells filed under this name is flagged as orphaned.
What kinds of wells does Annex Oil operate?
By product class, 0 (0%) 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 Sponseller, R 2 in Hillsdale, MI at 4,125 ft.
Notable wells operated by Annex Oil
| Well | API # / state ID | Status | Type | Location | Operator | Depth |
|---|---|---|---|---|---|---|
| Sponseller, R 2 | 21-059-22297 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,125 ft |
| Sponseller, Robert 3-A | 21-059-25064 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,120 ft |
| Sponseller, R 4 | 21-059-23357 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,117 ft |
| Sponseller, Robert 5 | 21-059-27093 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,101 ft |
| Sponseller, R 1 | 21-059-22180 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,087 ft |
| Arno, George Jr. 1 | 21-059-39938 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,070 ft |
| Lyons, Theon 4 | 21-059-38254 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,060 ft |
| Williams, James E 1 | 21-059-36745 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,006 ft |
| Lyons, Theon 2 | 21-059-37040 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,003 ft |
| Lyons, Theon 3 | 21-059-37070 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 4,000 ft |
| Sword Merlin 1 | 21-059-36863 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 3,907 ft |
| Lyons, Theon 1 | 21-059-36211 | Plugged & abandoned | Other type | Hillsdale, MI | Annex Oil Corp | 3,896 ft |
Deepest first where depth is published. See all 18 wells →
Frequently asked questions
How many wells does Annex Oil operate?
Annex Oil is the operator of record for 18 catalogued oil & gas wells, with the largest concentration in Michigan (18). Only wells in states WellCensus has ingested are counted.
How many of Annex Oil's wells are still active?
0 of Annex Oil's catalogued wells are active; 14 are plugged & abandoned.
In which states does Annex Oil operate wells?
Annex Oil is the operator of record for wells in Michigan (18).
Does Annex Oil operate mostly oil or gas wells?
0 of Annex Oil's catalogued wells are oil wells and 0 are gas wells; the rest are injection, service or unclassified wells.
What is Annex Oil's deepest well?
Among wells with a published depth, Sponseller, R 2 in Hillsdale, MI is the deepest at 4,125 ft.
Where Annex 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, “Annex Oil — well portfolio”, https://wellcensus.com/operators/annex-oil-121768 (data as of October 10, 2026).
Dataset updated . Operator portfolios are resolved from raw state registry filings (exact-normalized names; subsidiaries stay separate).