Patent ID: 6531868
Filing Date: 2003-03-11
Classification: G01N,G01R,G01V

Abstract:
A method for making nuclear magnetic resonance (NMR) measurements of a geologic formation using a NMR logging tool, comprising the steps of:providing a static magnetic field in a volume of said formation; applying downhole oscillating magnetic fields according to a forced magnetization recovery pulse sequence &sgr;iâˆ’&pgr;/2(+x)âˆ’[tcpâˆ’&pgr;âˆ’tcpâˆ’echo]jâˆ’tcpâˆ’&pgr;/2(âˆ’x) â€ƒwhere &tgr;i is a variable delay, and i&gE;1; j&gE;1; and +x and âˆ’x denote phases of the Larmor frequency of the carrier of the pulse with respect to a continuous wave Larmor frequency signal; tcp is tile Carr-Purcell spacing, wherein the echo train defined by tcp and j in the sequence is shorter than the longest expected characteristic signal decay time component T2 ; and measuring the induced NMR echo signals.