METHOD AND APPARATUS FOR RESERVOIR FLUID CHARACTERIZATION IN NUCLEAR MAGNETIC RESONANCE LOGGING

摘要

A method and apparatus for obtaining a parameter of interest relating to aregion proximate a nuclear magnetic resonance (NMR) logging tool suitable forsubterranean well logging is disclosed. The nuclei of the region are subjectedto a pulsed NMR technique and are productive of NMR logging data, the nucleiof the region characteristically having a longitudinal relaxation time T1distribution and an apparent transverse relaxation time T2app distribution. Inresponse to the NMR logging data, an R distribution is defined as R= T1/T2app, the T2app and R distributions are processed as separate bins, alongwith the NMR logging data, according to a two-dimensional inversion model, anda signal intensity map of R versus T2app is provided that is representative ofthe parameter of interest relating to the region. In response to a high-intensity signal on the map being within a first range of T2app values and afirst range of R values, the presence of a light hydrocarbon within the regionis identified.