DTC
Schlumbergerµs/ftSonic (Corrected Delta-T)
Borehole-corrected compressional slowness — the interval transit time after environmental corrections. The preferred sonic curve for porosity and seismic ties when available, since it removes the tool and hole effects present in raw DT.
- Property
- Compressional Slowness
- Acoustic Slowness
- Quantity
- time per length
- µs/ft · ms/ft · ms/cm · ns/m · ns/ft · ms/m · 0.001 h/ft · min/m · min/ft · h/km · µs/in · s/m · s/cm · ms/in · µs/m · s/in · s/ft
- Typical range
- ~52.1–99.4 µs/ft
- µs/ft, from matrix (~40–55) to shale or high-porosity (>100)
Logging tool
No logging tool is associated with this curve.
Service company
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View Schlumberger mnemonics →What is the DTC curve?
How it's measured
A borehole-compensated sonic tool times the first compressional arrival across receiver pairs, then applies corrections for hole size, tool tilt, and mud slowness — yielding a cleaned slowness in µs/ft.
How it's used
The same role as DT — sonic porosity, acoustic impedance and synthetic seismograms, and geomechanics — but with environmental corrections already applied, so it is usually the version fed into quantitative workflows.
Common gotchas
Still subject to cycle-skipping in poor signal and a compaction correction in unconsolidated sands. Confirm which corrections a vendor's 'corrected' curve actually includes before trusting it blindly.
In LAS files
Recorded as DTC (or DT, AC) in µs/ft. Where both DT and DTC exist, DTC is generally the interpretation-ready curve.
Also seen with DTC in real logs
Curves that appear alongside DTC in the same wells across the public corpus.