Measuring pore connectivity by pulsed field gradient diffusion editing with hydrocarbon gases.
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.
Flaum
Mark
M
Department of Chemical Engineering, Rice University MS 362, Rice University PO Box 1892, Houston, TX 77251-1892, USA. mflaum@rice.edu
Hirasaki
George Jiro
GJ
Flaum
Charles
C
Straley
Christian
C
D004058:Diffusion; D004980:Ethane; D005740:Gases; D055593:Geological Phenomena; D005844:Geology; D009682:Magnetic Resonance Spectroscopy; D008697:Methane; D016062:Porosity; D014867:Water
D005740:Gases; D014867:Water; D004980:Ethane; D008697:Methane