Preconditioning spins near a nuclear magnetic resonance region

US6492809B1 · kind B1 · utility

Assignee

• SCHLUMBERGER TECHNOLOGY CORPORATION · US

Inventors

• Peter Speier · Erlangen, DE
• Krishnamurthy Ganesan · Sugar Land, US

Key dates

• Filing date: Dec 4, 1998
• Grant date: Dec 10, 2002
• Expiry date: Dec 4, 2018

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N24/081
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and an apparatus for obtaining NMR measurements are disclosed. An NMR measurement apparatus, the measured sample, or both elements may be subjected to motion during the measurement. The envelope of an RF carrier signal is modulated according to an envelope to generate a first sequence of RF pulses. The envelope, the phase of the RF signal, and/or a static magnetic field may be varied during the radiation of the first sequence to substantially saturate a first region of the sample. The first sequence may include additional RF refocusing pulses that, when coupled with movement of the NMR measurement apparatus or sample, may also be used to substantially saturate the first region. A second sequence of RF pulses is radiated to establish a resonance region within the first region and measure an attribute of the sample.