R. L. Kleinberg, C. Flaum, and C. Straley
Schlumberger-Doll Research, Ridgefield, Connecticut, USA
P. G. Brewer, G. E. Malby, E. T. Peltzer III, and G. Friederich
Monterey Bay Aquarium Research Institute, Moss Landing, California, USA
J. P. Yesinowski
Naval Research Laboratory, Washington, D. C., USA
Journal Geophysical Research (2003) 108(B3): 2137. doi:10.1029/2001JB000919.
Received: 2001 August 12.
Revision received: 2002 June 6.
Accepted: 2002 December 9
Published: 2003 March 7.
Proton nuclear magnetic resonance (NMR) of liquid water can be used to indirectly detect and assay methane hydrate in opaque earth materials. It is also potentially useful for quantifying pore size control of hydrate formation, and for estimating in situ hydraulic permeability of hydrate-affected earth formations. The method is quantitative, nondestructive, and volumetrically averaging over a spatially selected region. In the first controlled validation of this measurement, we have used NMR to measure changes in the liquid water content of sediment and rock resulting from methane hydrate formation. Hydrates were artificially formed at the seafloor by introducing methane into tubes containing sediments or rock saturated with seawater; after several weeks the samples were visited by a remotely operated vehicle on which NMR equipment was mounted. Reduction of the NMR signal indicated hydrate had formed in the sample within a well-defined measurement volume. Hydrate content determined by NMR quantitatively predicted the volume of methane gas evolved during subsequent dissociation.
© 2003 by American Geophysical Union.
We wish to thank K. Winkler for performing laboratory sonic measurements on rock samples, W. Smith for sample preparation and petrophysical measurements, P. Frulla and J. Massey for laboratory NMR measurements on rock samples, and M. D. Hurlimann for modeling the spatial response function and the gas response of the CMR. Bulk methane hydrate samples were kindly provided by L. A. Stern and S. H. Kirby of the U.S. Geological Survey, Menlo Park, California. We also wish to thank the captain and crew of the R/V Point Lobos and the R/V Western Flyer and the pilots of the ROV Ventana and ROV Tiburon.