MLchartDataset catalogue

U-tube effect

Term · Oil and gas · MLC-T-OAG-004004

The tendency of fluid to flow between the drill string and the annulus, like liquid levelling in the two arms of a U-shaped tube, when the two columns have different densities and the pumps are off. It occurs after a heavy slug or cement is pumped, producing flow back at surface or free fall of the heavier fluid. Swab and surge pressures differ, since they come from pipe movement and not from a density difference.

Table 1. Record
IdentifierMLC-T-OAG-004004
FieldOil and gas
SubjectDrilling Fluids
Record as JSON 
{
  "id": "MLC-T-OAG-004004",
  "term": "U-tube effect",
  "field": "Oil and gas",
  "definition": "The tendency of fluid to flow between the drill string and the annulus, like liquid levelling in the two arms of a U-shaped tube, when the two columns have different densities and the pumps are off. It occurs after a heavy slug or cement is pumped, producing flow back at surface or free fall of the heavier fluid. Swab and surge pressures differ, since they come from pipe movement and not from a density difference.",
  "subject": "Drilling Fluids",
  "url": "https://mlchart.com/terminology/oil-and-gas/u-tube-effect/"
}

Record 4,254 of 4,469 in Oil and gas terminology (MLC-0103). Request the full dataset.