title: Comparative measurements between a new logging tool and a reference instrument.
abstract: Measurements were performed on reference samples (D2O-H2O mixtures) and on highly heterogeneous rocks (Vosges sandstone) with a new logging tool designed to give access to a high spatial resolution, below 1.5 cm on the vertical scale, for a toroidal sensitive volume of 20 cm3. The results were compared to measurements obtained on a clinical magnetic resonance imaging (MRI) equipment working at the same frequency (4.3 MHz). T2 differences as high as 30% were observed for the reference samples; the shortest values were obtained with the logging tool. Porosity profiles of the rock samples were also compared to reference profiles obtained with a conventional computed tomography (CT) scanner. Both nuclear magnetic resonance (NMR) measurements underevaluate porosity by 2-4% for short T2 values (< 10 ms).
authors.affiliation: LETI (CEA Technologies Avancées), Grenoble, France.
authors.forename: M
authors.initials: M
authors.lastname: Locatelli
authors.forename: H
authors.initials: H
authors.lastname: Mathieu
authors.forename: S
authors.initials: S
authors.lastname: Bobroff
authors.forename: G
authors.initials: G
authors.lastname: Guillot
authors.forename: B
authors.initials: B
authors.lastname: Zinszner
mesh_terms: D004867:Equipment Design; D019015:Geologic Sediments / Q000032:analysis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D016062:Porosity; D012016:Reference Values; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation