By Campbell Gough, Product Manager, OilfieldH2O
Understanding arcane Class I wells isn’t just regulatory minutiae—it’s operational foresight.
As the Texas Railroad Commission (RRC) rolls out new permitting rules for Class II injection wells in the Permian Basin, a category of wells is coming into sharper focus: Class I industrial disposal wells. While historically overlooked by many oil and gas operators, these facilities—regulated by the Texas Commission on Environmental Quality (TCEQ)—are becoming a critical source of subsurface intelligence.
Here’s why.
A Shift in Subsurface Strategy
Most subsurface planning has traditionally centered on Class II wells—used to dispose of oilfield fluids under RRC oversight. But with the RRC’s June 2025 rule changes requiring expanded Area of Review (AOR) analyses that now include all well classes, they are being pushed to consider a broader set of injection activity in proximity to their own assets.
That includes industrial Class I wells, which are permitted by facility rather than individually and are designed to higher construction standards than their Class II counterparts. These wells often inject deeper, operate under stricter mechanical integrity requirements, and—importantly—are supported by valuable geologic, engineering, and performance data.
What Makes Class I Wells Unique?
Class I wells handle some of the state’s most hazardous liquid wastes but have a lower risk profile than Class II wells. They are fewer in number and typically co-located at secure industrial sites. They have steady disposal rates in controlled conditions. The smaller number of wells allows for closer regulatory oversight, enabling risk to be engineered out during the planning phase. Class I facilities may encompass multiple drilled or undrilled wells, complicating geospatial and volumetric analysis. Most are drilled deeper than Class II wells and must meet more rigorous standards for casing, cementing, and MIT testing.
Why It Matters for SWD Wells and Carbon Storage Planning
Permitting Impact
Under the new RRC permitting guidelines, Class II operators must analyze all wellbores that intersect the injection zone within a 0.5–2-mile radius. Class I wells, even if undrilled or plugged, can represent containment risks or complicate pressure modeling. Identifying and understanding these wells early in the AOR process can mean the difference between a smooth application and costly delays.
Carbon Storage Relevance
Class I data is also gaining relevance for developers of carbon storage, Class VI projects. Class I wells often inject into formations being considered for CO₂ sequestration and offer decades of injectivity and data to inform project feasibility. Data such as permitted injection volumes and pressure, as well as MIT and construction history, reveal the formation’s response and pressure evolution over time.
Nuances in the Data Matter
Class I well records offer valuable insights—but only when interpreted with attention to the nuances. For example, when evaluating Class I records, operators should be aware of important distinctions between:
- Legal status (e.g., active, permitted) does not guarantee the well was drilled.
- Physical status may show a well is plugged, even if the permit’s Legal status remains active.
- Coordinates are often at the facility level unless updated with as-drilled location data. Or, coordinates to surface hole are available only for one well in a group of several listed in a permit.
Understanding these details and taking the time to review the permit documents are essential for modeling pressure propagation, containment zones, and potential migration risks.
How OilfieldH2O Helps
B3 Insight’s OilfieldH2O platform integrates fragmented Class I data into a structured, geospatially-attributed dataset. Key capabilities include:
- Geospatial Attribution: Cross-referencing TCEQ filings, BEG reports, and legacy permits to extract and display well locations and characteristics.
- Integrated View: Class I wells appear alongside Class II, III, pressure gradient maps, seismicity overlays, and land data.
- Regulatory Compliance: Supports the RRC’s AOR requirements by providing access to verified well data and documentation.
- Scenario Planning: Class I injection behavior informs Class VI site selection and reservoir suitability modeling.
Class I Wells: From Obscure to Operationally Critical
As the Permian enters an era of pressure-limited disposal, tighter regulatory scrutiny, and carbon storage expansion, Class I wells have moved from peripheral curiosity to a critical source of subsurface intelligence.
They are part of the planning toolkit for any operator navigating water disposal constraints or exploring CO₂ injection feasibility.