ITT
Schlumberger1/² msInterval Transit Time
The acoustic interval transit time — sonic slowness, how long a compressional wave takes to cross a foot of formation. The same measurement family as DT, and the direct input to sonic porosity and seismic ties.
- Property
- Integrated Slowness
- Acoustic Travel Time
- Quantity
- time
- 1/² ms · wk · µs · a[t] · ps · 100 ka[t] · s · Ma[t] · fa · min · a · cs · ca · h · ka[t] · ds · Ea[t] · ms · hs · d · ns · Ta[t] · na · Ga[t]
- Typical range
- ~0–1 msec
- 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 ITT curve?
How it's measured
A sonic tool times the first compressional arrival between receivers and reports the slowness (transit time per foot).
How it's used
Sonic porosity, acoustic impedance for seismic ties, and geomechanics — identical in role to DT, of which ITT is the descriptive name (interval transit time).
Common gotchas
Cycle-skipping and noise in poor conditions, and a compaction correction in unconsolidated sands. Where both ITT and DT appear they are usually the same quantity under different mnemonics.
In LAS files
Recorded as ITT (or DT, DTC) in µs/ft. Treat it as the sonic slowness curve.
Also seen with ITT in real logs
Curves that appear alongside ITT in the same wells across the public corpus.