HR: 0830h
AN: OS51B-0844    [PDF]
TI: Effects of THF hydrate concentration and cyclic hydrate formation on sediment bulk properties.
AU: * Scott, C L
EM: scotcl@inel.gov
AF: INEEL, P.O. Box 1625, Idaho Falls, ID 83415 United States
AU: Johnson, J T
EM: johnjt@inel.gov
AF: INEEL, P.O. Box 1625, Idaho Falls, ID 83415 United States
AU: Kunerth, D C
EM: DCK2@inel.gov
AF: INEEL, P.O. Box 1625, Idaho Falls, ID 83415 United States
AU: Rector, J W
EM: jwrector@lbl.gov
AF: University of California at Berkeley, University of California, Berkeley, CA 94720 United States
AU: Weinberg, D M
EM: weinbe@inel.gov
AF: INEEL, P.O. Box 1625, Idaho Falls, ID 83415 United States
AB: In earlier experiments, using a near stoichiometric tetrahydrofuran (THF) mixture in sand, we found that this type II hydrate evolved as a second solid phase in a multiphase system. The results indicated the hydrate species formed in the pore bodies and only affected the bulk properties of the sediment. Shear properties changed only when the remaining pore fluid (water) freezes and welds the two solid phases (Kunerth 2001). The original experiments, and those presented, here were performed in an insulated one-dimensional (1-D) acoustic reflection cell that allowed for the simultaneous measurement of the temperature gradient and the reflected P and S waveforms as a function of time and temperature. The experiments presented here address questions of the effect of THF concentration, and resulting percent hydrate, on the bulk properties and the effect of cyclic loading (hydrate formation and disassociation) on the sediment system. The concentration experiments were conducted by iteratively raising the concentration of THF in the sediment cell and running the system through a hydrate formation cycle. Corresponding THF concentration was then found through IR spectroscopy. Cyclic experiments were performed by iteratively forming and disassociating hydrates from a near stoichiometric THF mixture. Initial results from the concentration experiments show amplitude variation with concentration and results will be presented with respect to common mixing models. Cyclic results showed amplitude behavior that may be associated with structural or sediment packing changes.
DE: 0930 Oceanic structures
DE: 0933 Remote sensing
DE: 0935 Seismic methods (3025)
DE: 4299 General or miscellaneous
DE: 5199 General or miscellaneous
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting