title: Measuring pore connectivity by pulsed field gradient diffusion editing with hydrocarbon gases.
abstract: Measurements of time-dependent diffusion are performed on a rock sample saturated first with water, then methane and finally ethane. The gases were selected because their increased diffusivities and relaxation times allow probing greater length scales than water and because of their practical relevance. The nuclear magnetic resonance measurements employed pulse field gradient diffusion editing pulse sequences, allowing analysis of D(t) as a function of relaxation time. Very different D(t) behaviors are observed for different relaxation times, including indications of connected pore networks at moderate relaxation times.
authors.affiliation: Department of Chemical Engineering, Rice University MS 362, Rice University PO Box 1892, Houston, TX 77251-1892, USA. mflaum@rice.edu
authors.forename: Mark
authors.initials: M
authors.lastname: Flaum
authors.forename: George Jiro
authors.initials: GJ
authors.lastname: Hirasaki
authors.forename: Charles
authors.initials: C
authors.lastname: Flaum
authors.forename: Christian
authors.initials: C
authors.lastname: Straley
mesh_terms: D004058:Diffusion; D004980:Ethane; D005740:Gases; D055593:Geological Phenomena; D005844:Geology; D009682:Magnetic Resonance Spectroscopy; D008697:Methane; D016062:Porosity; D014867:Water
chemical_list: D005740:Gases; D014867:Water; D004980:Ethane; D008697:Methane