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1. (WO2011159294) NUCLEAR MAGNETIC RESONANCE LOGGING TOOL HAVING AN ARRAY OF ANTENNAS

Pub. No.:    WO/2011/159294    International Application No.:    PCT/US2010/038844
Publication Date: Dec 22, 2011 International Filing Date: Jun 16, 2010
IPC: G01V 3/00
Applicants: HALLIBURTON ENERGY SERVICES, INC.
MORYS, Marian, L.
KNIZHNIK, Sergei
JACHMANN, Rebecca, C.
EPSTEIN, Robert
Inventors: MORYS, Marian, L.
KNIZHNIK, Sergei
JACHMANN, Rebecca, C.
EPSTEIN, Robert
Title: NUCLEAR MAGNETIC RESONANCE LOGGING TOOL HAVING AN ARRAY OF ANTENNAS
Abstract:
Various disclosed nuclear magnetic resonance (NMR) logging systems and methods employ an array of antennas to provide increased resolution without sacrificing signal-to-noise ratio. Certain method embodiments include: establishing a static magnetic field (BO) with a tool moving along a borehole through a formation; concurrently driving a multiple antenna cells to produce a radio frequency field (Bl) in said formation; measuring an individual response from each antenna cell as nuclear spins undergo precession in the formation; and determining at least one characteristic relaxation time of the formation based at least in part on the individual response. The individual responses can be associated with positions where the individual responses were measured, and the relaxation time can be determined from a combination of those responses associated with a given position. Certain responses may be excluded due to tool motion that degrades the measured response.