title: Interpretation of restricted diffusion in sandstones with internal field gradients.
abstract: We report on experiments to characterize internal magnetic field gradients that are caused by magnetic susceptibility differences between the solid phase and the fluids filling the pore space. Our measurements focus on low-field relaxometry of brine and oil in sandstones from various reservoirs around the world. Our results show the need to understand the dependence of internal field gradients on diffusion length, pore size- and fluid distribution in order to predict the impact of internal gradients on the interpretation of NMR experiments.
authors.affiliation: Shell International Exploration & Production, Inc., 3737 Bellaire Blvd, Houston, TX, USA. appel@shellus.com
authors.forename: M
authors.initials: M
authors.lastname: Appel
authors.forename: J J
authors.initials: JJ
authors.lastname: Freeman
authors.forename: J S
authors.initials: JS
authors.lastname: Gardner
authors.forename: G H
authors.initials: GH
authors.lastname: Hirasaki
authors.forename: Q G
authors.initials: QG
authors.lastname: Zhang
authors.forename: J L
authors.initials: JL
authors.lastname: Shafer
mesh_terms: D004058:Diffusion; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D055585:Physical Phenomena; D010825:Physics; D016062:Porosity; D012492:Salts; D012822:Silicon Dioxide; D014867:Water
chemical_list: D012492:Salts; C017082:brine; D014867:Water; D012822:Silicon Dioxide