MLchartDataset catalogue

Excavation effect

Term · Oil and gas · MLC-T-OAG-001343

A decrease in the apparent neutron porosity below the value expected from the hydrogen indices of the pore fluids, which occurs when a low-hydrogen fluid such as gas replaces part of the liquid in the pores. The reading falls by more than a volume-weighted average of the hydrogen indices would predict, so it must be corrected when porosity and gas saturation are estimated in gas zones. The name reflects gas excavating hydrogen from the rock volume that the tool investigates.

Table 1. Record
IdentifierMLC-T-OAG-001343
FieldOil and gas
SubjectFormation Evaluation
Record as JSON 
{
  "id": "MLC-T-OAG-001343",
  "term": "Excavation effect",
  "field": "Oil and gas",
  "definition": "A decrease in the apparent neutron porosity below the value expected from the hydrogen indices of the pore fluids, which occurs when a low-hydrogen fluid such as gas replaces part of the liquid in the pores. The reading falls by more than a volume-weighted average of the hydrogen indices would predict, so it must be corrected when porosity and gas saturation are estimated in gas zones. The name reflects gas excavating hydrogen from the rock volume that the tool investigates.",
  "subject": "Formation Evaluation",
  "url": "https://mlchart.com/terminology/oil-and-gas/excavation-effect/"
}

Record 1,446 of 4,469 in Oil and gas terminology (MLC-0103). Request the full dataset.