MLchartDataset catalogue

Shifted spectrum

Term · Oil and gas · MLC-T-OAG-003373

An NMR T2 distribution that moves toward shorter times when the echo spacing is lengthened, because diffusion in the magnetic field gradient adds relaxation. Water in small pores shifts little, while gas and light oil, with high diffusion coefficients, shift strongly, so comparing spectra acquired at short and long echo spacings identifies the hydrocarbon. The comparison is the basis of the shifted spectrum method for fluid typing.

Table 1. Record
IdentifierMLC-T-OAG-003373
FieldOil and gas
SubjectFormation Evaluation
Record as JSON 
{
  "id": "MLC-T-OAG-003373",
  "term": "Shifted spectrum",
  "field": "Oil and gas",
  "definition": "An NMR T2 distribution that moves toward shorter times when the echo spacing is lengthened, because diffusion in the magnetic field gradient adds relaxation. Water in small pores shifts little, while gas and light oil, with high diffusion coefficients, shift strongly, so comparing spectra acquired at short and long echo spacings identifies the hydrocarbon. The comparison is the basis of the shifted spectrum method for fluid typing.",
  "subject": "Formation Evaluation",
  "url": "https://mlchart.com/terminology/oil-and-gas/shifted-spectrum/"
}

Record 3,582 of 4,469 in Oil and gas terminology (MLC-0103). Request the full dataset.