METHOD AND APPARATUS FOR USING PULSED FIELD GRADIENT NMR MEASUREMENTS TO DETERMINE FLUID PROPERTIES IN A FLUID SAMPLING WELL LOGGING TOOL

摘要

A method for determining a formation fluid property includes acquiring a sui te of nuclear magnetic resonance (NMR) measurements of a fluid sample using a pulse sequen ce that includes pulsed field gradient pulses for encoding diffusion information, wherein eac h NMR measurement in the suite is acquired with a different value in a parameter i n the pulsed field gradient pulses for producing a different diffusion effect, wherein the acquiring is performed in a formation fluid sampling tool in a borehole; inverting the suite of NMR measurements to produce a distribution function that relates diffusion properties of the flu id sample with an NMR property of the fluid sample; and determining the formation fluid property from the distribution function.