Methodology & 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). Wells a state publishes without an API number are identified by the state’s own record ID instead — every Indiana well, for example, by its IGS ID, since Indiana doesn’t use API numbers. Current ingests:

The national orphan overlay is the USGS United States Documented Orphaned Well Database 2026 (doi 10.5066/P13FHBYG, published Sept. 30, 2026: 130,121 unplugged orphaned wells in 28 states). It supersedes the 2022 dataset (doi 10.5066/P91PJETI, 117,672 wells in 27states). Each federal record is merged onto the state’s own record by API number, or by the state ID where the state uses one (Indiana IGS IDs, Kentucky permit numbers); records with no identifier at all are kept as separate entries. Wells that were in the 2022 dataset but are not in the 2026 release are no longer marked orphaned on the strength of the federal list alone. The 2026 release also estimates surface and mineral ownership categories for each well; USGS says those estimates are not official, and WellCensus does not republish them.

Per-state coverage (honest scope)

The full US universe is roughly ~3 million drilled wells across 30+ producing states — no free public dataset carries all of them, and WellCensus doesn’t claim to. What it does carry: 23state registries, ingested directly from each regulator’s bulk data, with the gaps stated per state. “Location index” means the regulator’s bulk file with attributes is not scriptably available yet — well identity, coordinates and status class are live; operators and dates are queued.

Texasdeserves a straight answer: the RRC’s statewide surface-well index (1.3M+ wellbore locations, API + status symbol) is live here, but the RRC publishes its full-attribute files only through a manual file-transfer portal, so operator names and dates for Texas load in a follow-up enrichment pass rather than an automated feed.

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 101,832 canonical operators — 2,833,767 of 4,166,704wells are linked (location-index states publish no operator names yet). 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 4,166,704 wells are served on demand, but only the 4,164,324 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 them periodically — the table above shows when each source was last imported — re-resolves operators after each batch, and stamps every page with a machine-readable “Dataset updated” timestamp plus Dataset JSON-LD dateModified. USGS publishes its orphaned-well database as periodic releases (2022, then 2026); WellCensus loads each new release when it is published.

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 with licensing questions; bulk files are on /data-files and the API and MCP server on /developers.