Delta t stretch

{
  "id": "MLC-T-OAG-000992",
  "term": "Delta t stretch",
  "field": "Oil and gas",
  "definition": "An erroneously long transit time on a sonic log, produced when the received signal is weak and the tool's detector triggers late on the first arrival. It is a measurement artefact, not a genuinely slow formation, so it should not be read as porosity or gas. A related but larger error is cycle skipping, in which the detector triggers on a later cycle altogether.",
  "subject": "Formation Evaluation",
  "url": "https://mlchart.com/terminology/oil-and-gas/delta-t-stretch/"
}