Fluid caliper

{
  "id": "MLC-T-OAG-001499",
  "term": "Fluid caliper",
  "field": "Oil and gas",
  "definition": "A wellbore survey that finds the annular volume, and so the average hole size, by pumping a marker through the well and timing its arrival at surface against a measured flow rate. No downhole tool is run, and the result shows washout and sets the cement volume needed to reach the planned top of cement. It differs from a mechanical caliper log, which measures hole diameter directly with arms pressed against the wall.",
  "subject": "Drilling",
  "url": "https://mlchart.com/terminology/oil-and-gas/fluid-caliper/"
}