CA CalGEM Oil & Gas & Geothermal Wells - California Well Register

California's Dept of Conservation / CalGEM publishes its well register (WellSTAR) as a free public map service - every oil, gas and geothermal well ever filed with the state. This actor turns it into a queryable, charged-per-record API - for environmental due-diligence, mineral-rights and land research, and oil & gas supply-chain vetting.

What it covers

~242.5k wells across California (layer 0 of CalGEM's WellSTAR service). Each record carries:

Field	What it is
apiNumber	the 10-digit API number - the stable per-well key
status	Active (53.9k) / Idle (30.3k) / Plugged (146.6k, sealed) / Canceled / New / PluggedOnly / Unknown
wellType	Oil & Gas / Waterflood / Cyclic Steam / Steamflood / Observation / Gas Storage / Water Disposal / Dry Gas ...
operatorName	who operates the well (Chevron, Aera Energy, California Resources...)
county / district	location (Kern is the giant; offshore areas are suffixed 'Offshore')
fieldName / areaName	producing field
leaseName / wellNumber	lease and well-on-lease identity
section / township / range / baseMeridian	PLSS survey location
spudDate / spudYear	when the well was first drilled
inHPZ	verified high-pressure-zone wells
confidential / directional	flags
latitude / longitude	coordinates

Typical questions

• "How many active wells does this operator run in Kern County?"
• "Which wells are in a verified HPZ near this township/range?"
• "Every plugged well on this lease - did the site get sealed?"
• "Where are California's gas-storage wells (for storage-safety diligence)?"
• "New wells spudded since 2020 in Kern County."

Honest limits

The register is a status snapshot, not a production ledger: it carries no depth, plug-report or bond columns, and no per-well "last updated" timestamp (CalGEM exposes those only through other systems). Spud date is a text column, so year filtering happens after a bounded scan. Don't build depth-history claims on this data.

Inputs

Input	What it does
status	Active (default when no other filter is set) / Idle / Plugged / Canceled / PluggedOnly / New / Unknown / NotCalGEMJurisdiction. Leave empty to search all statuses (use with a county/operator/well-type filter for a full-status view)
county / operator / leaseName / wellNumber	name substrings
wellType	code or label (OG / 'Oil & Gas', WF / 'Waterflood', ...)
apiNumber	exact 10-digit API - single well
inHPZ / confidential / directional	yes/no flags
spudYearFrom / spudYearTo	first-drilled year range (record runs; not combinable with aggregate)
latMin/latMax/lonMin/lonMax	bounding box
aggregate / groupBy	one row per group (county / status / wellType / operator / field / district) with a count
maxResults	cap records (default 50)

Default run = up to 50 active wells - fast enough for the daily auto-test, and a live slice of California's operating wells.

Note: a run is capped at $5 of usage - a request large enough to reach it (roughly 5,000 records at the entry price) is cut off part-way, and the truncated run still reports success. For whole-corpus counts, use aggregate.

Example inputs

One well by API number - The 10-digit API number is the stable per-well key.

{"apiNumber": "0403703161", "maxResults": 5}

Active wells run by one operator in one county - operator and county are substring matches.

{"status": "Active", "operator": "Chevron", "county": "Kern", "maxResults": 25}

Verified high-pressure-zone wells in one county

{"inHPZ": "Verified HPZ", "county": "Los Angeles", "maxResults": 25}

Wells by status - aggregate=true returns one summary row per group with a count.

{"aggregate": true, "groupBy": "status"}

Low cost

From $0.001 per record - billed only for the rows you use, and each record is metered individually.

The register is 242,545 wells across California's oil, gas and geothermal fields. The source publishes its drill dates as strings, not dates - so a naive year filter would silently mis-sort records - and its aggregate endpoint ignores its own row-count limit. We sidestep both: year filtering runs as a bounded scan on our side, aggregate rows are re-sliced correctly on our side, and the source's quirky status values (a whitespace-less NotCalGEMJurisdiction, for one) are matched exactly rather than by sloppy substring. You query a clean well register by county / operator / status / API number; the data quirks stay on our side.

Example output

One well - apiNumber=0403703161 returns the single well:

{
 "platform": "ca-wells",
 "source": "calgem-wellstar",
 "mode": "rows",
 "apiNumber": "0403703161",
 "leaseName": "Lease by Tidelands Oil Production Co.",
 "wellNumber": "Z1 61",
 "status": "Plugged",
 "wellTypeCode": "OG",
 "wellType": "Oil & Gas",
 "operatorName": "Tidelands Oil Production Co.",
 "fieldName": "Wilmington",
 "areaName": "Fault Block V",
 "district": "Southern",
 "county": "Los Angeles",
 "section": "11",
 "township": "05S",
 "range": "13W",
 "baseMeridian": "SB",
 "spudDate": "03/07/1962",
 "spudYear": "1962",
 "confidential": "N",
 "directional": "Y",
 "inHPZ": "Verified HPZ",
 "latitude": "33.75258636",
 "longitude": "-118.20665741",
 "groupKey": "",
 "groupCount": ""
}

aggregate=true, groupBy=status - wells by status:

Plugged    146.6k
Active      53.9k
Idle        30.3k

Source

• CalGEM WellSTAR (California Dept of Conservation) - official, free public map service.