MAGNETIC RESONANCE PULSE SEQUENCES AND PROCESSING

摘要

A nuclear magnetic resonance (NMR) apparatus includes a carrier configured to be deployed in a borehole, a magnet assembly configured to generate a static magnetic field in an earth formation, and at least one transmitting assembly configured to generate an oscillating magnetic field in a volume of interest within the formation. The apparatus also includes a pulse generator configured to apply a direct-echo pulse sequence to the at least one transmitting assembly, the direct-echo pulse sequence having a plurality of successive pulses including a first pulse and a second pulse configured to generate a first direct NMR echo, and a third pulse, the third pulse selected to at least partially separate a stimulated NMR echo from a second direct NMR echo occurring after the third pulse. The apparatus further includes at least one receiving assembly configured to detect the first and second direct echoes of an NMR echo train.

主权项

1. A nuclear magnetic resonance (NMR) apparatus for estimating properties of an earth formation downhole, the apparatus comprising:
a carrier configured to be deployed in a borehole in the earth formation; a magnet assembly disposed in the carrier and configured to generate a static magnetic field in the formation; at least one transmitting assembly disposed in the carrier and configured to generate an oscillating magnetic field in a volume of interest within the formation; a pulse generator configured to apply a direct-echo pulse sequence to the at least one transmitting assembly, the direct-echo pulse sequence having a plurality of successive pulses, the plurality of successive pulses including a first pulse and a second pulse configured to generate a first direct NMR echo, and a third pulse, the third pulse selected to at least partially separate a stimulated NMR echo from a second direct NMR echo occurring after the third pulse; and at least one receiving assembly disposed in the carrier and configured to detect the first and second direct NMR echoes of an NMR echo train.