Oklahoma Stopped Its Earthquakes by Shrinking Its Plumbing. Now It Needs the Pipes Back.
Oklahoma solved an earthquake crisis by shrinking its disposal capacity. Statewide Class II injection has fallen about 40% from its 2015 peak, and effectively the entire cut came out of the deep Ordovician zone — the Arbuckle among them — while shallower Pennsylvanian injection stayed roughly flat. The state still puts about twice as much fluid back into the ground as it produces for sale. This paper argues that with gas demand pulling new drilling into the Anadarko Basin, the binding limit on Oklahoma's next production cycle is not the rock but how many barrels of water an acre is legally and physically allowed to dispose of, and who controls that permission.
Key findings
Statewide injection down since 2015
Barrels reinjected per barrel sold
Marketed gas in 2025, a six-year high
Methodology
Statewide and zone-level Class II injection volumes are indexed to the 2015 peak using Oklahoma Geological Survey monthly disposal data by geologic zone of completion, then read against the Corporation Commission's directive record — 33 directives, including the November 2016 Cushing plan with its tiered 6-, 10-, and 15-mile response radii. Cost exposure is priced by moving a barrel of water from pipeline to trucking at a documented 20:1 water-to-oil ratio, which converts disposal logistics into a per-barrel-of-oil figure.
What the scenarios show
| Exposure case | Share modeled | Annualized exposure |
|---|---|---|
| Deep Ordovician injection | Since 2015 | Down roughly half |
| Shallow Pennsylvanian injection | Since 2015 | Roughly flat |
| Pipeline lost to trucking | 20:1 water-oil ratio | About $34 per barrel of oil |
One M4.0 event triggered orders against 54 wells: 7 shut in within 6 miles, 16 cut by a quarter at 10 miles, and 31 held to their last 30-day average at 15 miles, with compliance due inside two weeks. The seismic program worked — earthquake rates fell by roughly a factor of four — but the capacity withdrawn to achieve that has not returned, and nothing in the current framework returns it.
Data sources
- —Oklahoma Geological Survey — Open-File Report OF1-2026, Class II saltwater disposal 2011–2025 by geologic zone
- —Oklahoma Corporation Commission — Advisory 4 (Cushing, November 2016), Area of Interest review, Carney directive
- —U.S. Energy Information Administration — Oklahoma natural gas marketed production
- —Railroad Commission of Texas — Permian saltwater disposal permitting guidelines, effective June 2025
- —Oklahoma Water Resources Board — Oklahoma Water / Energy Nexus
- —Morningstar DBRS — U.S. pipeline build-out analysis, January 2026