1. n. [Production Logging]

The fraction of a particular fluid measured in the vicinity of a small probe in a production well. The small, or local, probes respond digitally to the type of fluid in front of them, indicating gas, oil or water depending on the type of probe. The local holdup of oil, for example, is determined by the percentage of time the probe spends in front of oil.

See: bubble count,  electric probe,  holdup image,  local probe,  optical probe,  production log,  velocity image