SIGNAL PROCESSING METHOD FOR MULTIEXPONENTIALLY DECAYING SIGNALS AND APPLICATION TO NUCLEAR MAGNETIC RESONANCE WELL LOGGING TOOLS

摘要

A method of reducing bias error in nuclear magnetic resonance (NMR) spin-ech o signals. The method includes filtering the signals using a filter having a b andwidth inversely related to the length of time from the initiation of the measureme nt of the NMR signals. In a preferred embodiment, the NMR spin-echo signal measurement s are filtered using a moving average filter having an averaging span which increa ses with respect to the time elapsed from initiation of the spin-echo measurement seq uence.