URAN
SchlumbergerPPMUranium
Uranium concentration from spectral gamma ray. Uranium is mobile and often unrelated to clay — its spikes flag organic-rich source rock, phosphates, and fractures, and it is the component stripped out to form CGR.
- Property
- Uranium Concentration
- Concentration
- Quantity
- dimensionless
- Typical range
- ~0.5–7.3 PPM
- parts per million (ppm)
Logging tool
No logging tool is associated with this curve.
Service company
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How it's measured
From the uranium emission window (1.76 MeV, bismuth-214 in the uranium series) of the spectral gamma tool, reported in ppm.
How it's used
Source-rock and organic-matter indication, fracture, stylolite and phosphate detection, and explaining GR hot streaks that are not shale. Subtracting it from GR yields the cleaner CGR.
Common gotchas
Because uranium moves with fluids, it can concentrate in fractures and permeable streaks — high uranium is not high clay. It is the noisiest of the three spectral channels.
In LAS files
Recorded as URAN (or U) in ppm, with POTA and THOR. A high URAN with a normal CGR marks a uranium spike.
Also seen with URAN in real logs
Curves that appear alongside URAN in the same wells across the public corpus.