Geothermal exploration in Cornwall, England, has gained significant attention due to the region’s unique geological conditions that make it suitable for harnessing geothermal energy. Cornwall is known for its large granite formations, which have high heat-producing properties. The granite’s natural radioactive decay generates substantial heat, making it an excellent candidate for geothermal energy extraction.
Cornwall has a higher-than-average geothermal gradient, meaning the temperature increases more rapidly with depth compared to other regions. This enhances the potential for geothermal energy.
United Downs, Cornwall: a pre-drill prediction, tested by a 5 km well
Independent validation of Atomic Dielectric Resonance (ADR) against public data from the UK’s flagship deep-geothermal well.
See before you drill.
In November 2014, ADR produced a blind, pre-drill virtual borehole at the United Downs Deep Geothermal project in Cornwall — years before the UD-1 well reached depth. When the completed well was later cross-checked against the 2014 prediction, using publicly available UD-1 data, ADR’s predicted permeable zones fell within the intervals where the well went on to record its major mud losses — the field signature of permeability, and the single most important property for a geothermal well. The strongest energy troughs aligned with mapped faults, and the dielectric response tracked the distinct granite units the drill later encountered. This is a genuine “see before you drill” result, reported here with its limits as well as its wins.
A rare deep target with a public answer
United Downs, near Redruth, is the UK’s flagship deep-geothermal development. Its UD-1 well was drilled to around 5 km into hot Cornish granite to test permeability along a major fault structure — one of the most demanding onshore targets in the country, and a rare case where a deep, well-documented public dataset exists to test a prediction against.
What ADR did
ADR measures the dielectric response of the subsurface to a coherent pulsed electromagnetic signal, returning a depth profile — a “virtual borehole” — of material-property contrasts. At United Downs the virtual borehole UD-C2 was acquired in November 2014 and reported in 2015, entirely ahead of drilling. From the dielectric and energy responses it flagged three candidate permeable zones — at approximately 1,100 m, 4,100 m and 4,700 m. No drilling data existed at the time to guide it.
Assessed against the drilled well
Each finding is reported under VEXRAD’s four-tier evidence standard — nothing is claimed beyond what the data supports.
| Depth / feature | ADR pre-drill prediction (2014) | UD-1 well outcome | Read |
|---|---|---|---|
| ~1,070–1,800 m | High dielectric; permeable-zone pick ~1,100 m | Major mud losses (permeability) | Validated |
| ~4,540–5,010 m | High dielectric; permeable-zone pick ~4,700 m | Major mud losses (permeability) | Validated |
| ~4,100 m | Additional permeable-zone pick | Not separately confirmed | Candidate |
| Faults | Strongest energy-response troughs | Align with mapped UD-1 faults | Validated |
| Granite units | High dielectric zones | Track micro-granite, cross-course fault, Granite A & D | Validated |
Two of ADR’s three blind permeable-zone picks — made in 2014 — fall inside the intervals where UD-1 later recorded its major mud losses. For a geothermal well, permeability is the prize, and ADR flagged it ahead of the bit.
What this doesn’t claim
- Only one virtual borehole (UD-C2) was processed for this validation.
- The dielectric and energy parameters correlated well; the WMF and E-Gamma parameters did not, and the E-Gamma processing window differs from VEXRAD’s standard temperature setting.
- Permeability was inferred from the well’s mud-loss record — a robust field proxy, but not a direct measurement.
We report these plainly. A validated result is only worth as much as the honesty around it.
What it means for explorers and developers
United Downs shows ADR doing the one thing that most de-risks a deep well: flagging where permeability is likely, before the drill gets there. On a live project the method is sharper still — calibrated against one or two of your own logged holes first, then used to predict where, and where not, to drill.
Talk to us about your project