Underream

{
  "id": "MLC-T-OAG-003982",
  "term": "Underream",
  "field": "Oil and gas",
  "definition": "To enlarge a section of a wellbore below a restriction, such as a casing shoe or a previously drilled narrower hole. This is accomplished using an underreamer, a specialized tool with expandable cutting arms that are activated at a specific depth. Underreaming is distinct from hole opening, which enlarges the hole from the surface downward rather than below a restriction.",
  "subject": "Drilling",
  "url": "https://mlchart.com/terminology/oil-and-gas/underream/"
}