The most capital-dense oil basin in North America. 393,073 drilled wells across 32 counties in Texas and New Mexico. We went looking for what has been logged and what has been forgotten. What we found was a lesson in measurement.
Kansas, the first basin in this series, is 94% dark. The interesting question isn't whether Permian is worse or better. It's whether a basin this economically central, with operators this sophisticated, still hides most of its own subsurface record.
"Dark" here means the same thing it meant for Kansas: no publicly accessible log for that well. The floor is what a determined analyst could recover without paying a commercial data vendor.
28 counties in Texas (Andrews through Yoakum) plus 4 in New Mexico: Lea, Eddy, Chaves, Roosevelt. The county union is the defensible Permian boundary, more auditable than any single basin outline.
The state line runs down the middle of the Delaware Basin. It is also a data boundary.
The Texas Railroad Commission publishes a live ArcGIS feed. Layer 1 is every well location in the state. We filter to the Permian bbox, deduplicate surface holes, spatial-join to county polygons.
What the layer returns: API number, coordinates, symbol code. What it does not return: spud date, completion date, operator, status. For those, the RRC points to a separately maintained ASCII dump behind a JSF portal.
So the live answer to "when was this well drilled?" is: we don't know. We keep going.
OCD's API_Export MapServer returns each well with operator, spud year, status, plug date, total depth, a link to the well-details page, and a link to the scanned-files portal. Forty fields per row.
Different state, different IT shop, different answer to the same question. The asymmetry is the first finding, not an inconvenience to flatten.
TX lit = API appears in RRC's Well Logs layer (a registry of scanned TIFFs in the imaged log system, ~236k wells statewide).
NM lit = spud year ≥ 2002, OCD's digital-filing-era floor. We can't use the per-well "files" URL as a lit proxy: every NM well has one, whether or not the portal has actual logs behind it.
The state boundary is bureaucratic, not geological. The same Wolfcamp rock gets a scanned paper log in Reeves County and a digital log in Eddy County because two different regulators made two different choices a generation ago.
That's the row count in the RRC Well Logs layer, clipped to our bbox. On its face, it suggests a lit rate of 28%.
The next step is a lesson in what happens when you let a row count stand in for a well count.
The 38,397 missing rows are duplicate scans: the same API, multiple log entries. Some horizontal wells have thousands of per-stage log records in the registry. Deduplicate, and the Texas lit rate drops from 28% to 20.8%.
"Lit" is never one number. It's whatever definition survives the next level of scrutiny.
TX RRC publishes a separate Well Logs layer. NM OCD does not. The OCD imaging portal exists but has no bulk inventory we can query. Each well has a boilerplate deep-link into it, whether the portal holds a log behind that link or a blank shell.
We use a proxy: any NM well spudded in 2002 or later is counted as lit, based on OCD's own stated digital-filing-era floor. Wells with unknown or placeholder spud years (1900, 9999) are counted as dark by default.
32% of NM wells have a junk or unknown spud year. That's its own finding.
87,027 of 393,073 wells. Texas at 20.8%, New Mexico at 26.0% by our proxy. Most of the lit wells sit on a narrow band through the Midland Basin and the Delaware: the horizontal-drilling campaigns of the last fifteen years.
Kansas was 94% dark. Permian is 78% dark. The gap is 16 points. Both basins hide most of their own record; they just hide different centuries of it.
Texas wells are clipped to the Permian 28 and tinted amber when lit. New Mexico wells are tinted teal. Both datasets cross the same rock; the color change at the state line is not geological.
If you were analyzing the Wolfcamp as a single play, you'd pay for IHS or Enverus to flatten this boundary. That's the point: the boundary is not real, but the data cost of erasing it is.
We can only plot vintage for New Mexico. The Texas side is blank here by admission: no spud dates on the live feed.
The 1980s drop is the oil-price crash. The 2010+ spike is the horizontal transition. 32% of NM wells have no reliable spud year: another gap inside the gap.
The five most-lit counties are the Midland Basin core plus Eddy on the Delaware side: the exact geography of the horizontal campaign. Where operators are drilling today, logs follow. Where they aren't, logs don't.
The five least-lit counties are shelf and transitional plays. Hockley and Winkler are old vertical country on the Central Basin Platform. Chaves and Roosevelt are NM's northern and eastern margins: less rock, older wells, less filing.
NM's largest operator-of-record isn't a company. It's a placeholder for every well whose operator was never migrated into OCD's ONGARD digital system when it came online. 15,601 wells, 0% lit by our proxy, 16% of the NM Permian.
The named majors and independents cluster at 40–50% lit, roughly double the basin average. The horizontal-era operators are running a separate data regime.
Kansas was structurally dark: old plays, shallow oil, nobody ever had the incentive. Permian is selectively dark. The horizontal Wolfcamp is well-logged because operators need the logs to model the next pad. The vertical century underneath it is dark because those logs aren't load-bearing for anyone's decisions.
The gap persists not despite massive economic pressure, but because the pressure points somewhere else.
Kansas was the easy case: 94% dark, nobody surprised. Permian is the hard case. Well-resourced operators, sophisticated regulators, billions of dollars a month in active drilling, and still 78% of the historical record is unreachable to a public analyst. The series continues through the Appalachian, the Bakken, the SCOOP/STACK, and the D-J. Each basin has its own century it has stopped caring about.
Where this goes
I build the pipelines, county-grain analyses, and AI-assisted subsurface QC that close this kind of gap, across basins, regulators, and the geological detail that still matters. If you work any side of this, let's talk.
Sources: Texas RRC Public Viewer MapServer (layers 1, 2, 8) · New Mexico OCD API_Export MapServer · US Census 2010 TIGER county boundaries. Coordinates as published. Built with deck.gl and scrollama. Analysis: @salamituns.