Methodology & data sources
Dataset updated . Derived from public data sources.
Sources
WellCensus re-publishes the public well registries of state oil & gas regulators, unified under one schema and one canonical key: the API number (API-10, digits only; the handful of source rows without a usable API carry a state-record fallback key). Current ingests:
| Source | State | Records | Last import |
|---|---|---|---|
| ca_calgem_allwells | CA | 242,471 | Jul 8, 2026 |
| co_ecmc_wells | CO | 124,344 | Jul 8, 2026 |
| nd_dmr_wells | ND | 43,680 | Jul 8, 2026 |
| nm_ocd_wells | NM | 141,088 | Jul 8, 2026 |
| ok_occ_rbdms | OK | 456,064 | Jul 8, 2026 |
| us_usgs_dow | US | 117,609 | Jul 8, 2026 |
| wy_wogcc_wells | WY | 129,955 | Jul 9, 2026 |
The national orphan overlay is the USGS Documented Orphaned Wells dataset (doi 10.5066/P91PJETI, 2022 snapshot, 117,672 wells in 27 states), merged onto state records by API number where possible. Coming next: the Texas RRC wellbore database (~1.1M) and the Pennsylvania DEP registry (~252k).
Coverage matrix (honest gaps)
States publish different fields. Where a column reads “—” the registry doesn’t publish it (or the ingest doesn’t parse it yet) — well pages render those fields as absent rather than guessing.
| Registry | Coordinates | Dates | Depth | Operator |
|---|---|---|---|---|
| Oklahoma (OCC RBDMS) | 97% | — | — | 99% |
| California (CalGEM) | 100% | spud ~37% | — | 98% |
| New Mexico (EMNRD OCD) | 100% | spud 72% · plug 35% | 100% | 100% |
| Wyoming (WOGCC) | 100% | — | 100% | 99% |
| Colorado (ECMC) | 100% | spud 72% | 79% | 100% |
| North Dakota (NDIC) | 100% | spud 84% | 100% | 97% |
| Orphan-overlay states (USGS) | 100% | — | — | — |
Status & type normalization
Every state’s status/type codes are normalized to five status buckets (active, plugged, orphan, shut-in, other) and four type buckets, with the raw state code preserved on every well page. Dry holes and “abandoned” map to plugged except where a state’s program defines abandoned as unplugged-with-no-operator (orphan).
Operator resolution
Raw operator spellings are exact-normalized (case, punctuation, INC/LLC/CO/CORP suffixes) into 25,561 canonical operators — 1,129,203 of 1,232,530wells (91%+) are linked. No fuzzy matching: subsidiaries stay separate on purpose. State bookkeeping records (“NOT ASSIGNED”, pre-migration placeholders, orphan funds) are kept for completeness but excluded from rankings and search indexing.
Indexing policy (completeness gate)
All 1,232,530 wells are served on demand, but only the 1,232,459 wells carrying at least an operator link, a lifecycle date or coordinates are submitted for search indexing — records below that threshold are too thin to be useful search results. Depth figures above 35,000 ft are treated as source errors and excluded from rankings.
Refresh cadence
State registries republish daily-to-monthly; WellCensus re-ingests weekly (OK, ND, CO, NM) to monthly (CA, WY), re-resolves operators after each batch, and stamps every page with a machine-readable “Dataset updated” timestamp plus Dataset JSON-LD dateModified. The USGS orphan file is a static 2022 snapshot, re-checked for revisions.
Licensing & attribution
Source data is public record published by U.S. state and federal agencies. WellCensus compilations may be cited with attribution to “WellCensus (wellcensus.com)”. Contact kenny@hyder.me for bulk or API access.