LLS
Schlumbergerohm·mShallow Laterolog Resistivity
The shallow-reading focused-current resistivity, paired with the deep laterolog (LLD) to profile invasion in salt muds and hard rock. Its separation from LLD indicates the depth and resistivity of the invaded zone.
- Property
- Shallow Laterolog Resistivity
- Shallow Resistivity
- Quantity
- electrical resistivity
- Typical range
- ~1.3–78.8 ohm·m
- ohm·m, invaded-zone resistivity
Logging tool
No logging tool is associated with this curve.
Service company
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How it's measured
Focused survey current with a shallow depth of investigation reads resistivity near the borehole wall, requiring a conductive water-based mud path like all laterolog measurements.
How it's used
The shallow member of the dual-laterolog pair — LLD/LLS separation drives invasion correction and Rt/Rxo analysis, especially in carbonates and salt muds where induction is unreliable.
Common gotchas
It cannot run in oil-based mud. It reads the invaded zone, not Rt, and needs the micro-resistivity (MSFL) to fully pin down Rxo. Thin resistive beds distort the reading.
In LAS files
Recorded as LLS (or RLLS, RS) in ohm·m, alongside LLD and MSFL.
Also seen with LLS in real logs
Curves that appear alongside LLS in the same wells across the public corpus.