Authors: Yongkoo Seol and Timothy J. Kneafsey

Venue: 6th International Conference on Gas Hydrates (ICGH 2008), Vancouver, British Columbia, CANADA, July 6-10, 2008. http://www.icgh.org/ [external site]

Abstract: The effects of porous medium heterogeneity on methane hydrate formation, water flow through the heterogeneous hydrate-bearing sand, and hydrate dissociation were observed in an experiment using a heterogeneous sand column with prescribed heterogeneities. X-ray computed tomography (CT) was used to monitor saturation changes in water, gas, and hydrate during hydrate formation, water flow, and hydrate dissociation. The sand column was packed in several segments having vertical and horizontal layers with two distinct grain-size sands. The CT images showed that as hydrate formed, the water and hydrate saturations were dynamically redistributed by variations in capillary strength of the medium (the tendency for a material to imbibe water), which changed with the presence and saturation of hydrate. Water preferentially flowed through fine sand near higher hydrate-saturation regions where the capillary strength was elevated relative to the lower hydrate saturation regions. Hydrate dissociation initiated by depressurization varied with different grain sizes and hydrate saturations.

Related NETL Project
This presentation is related to the NETL project ESD05-048, “Laboratory Studies in Support of Characterization of Recoverable Resources from Methane Hydrate Deposits.” The overall objective of this proposal is to continue studies on the characterization and analysis of recoverable resources from gas hydrate deposits. The research will enhance the National Energy Technology Laboratory (NETL)-funded programs on Natural Gas Hydrate research and development by bringing new laboratory measurements and evaluation techniques to bear on the difficult problems of characterization and gas recovery from methane hydrate deposits.

Project Contacts
NETL – Robert Vagnetti (Robert.Vagnetti@netl.doe.gov or 304-285-1334)
Lawrence Berkeley National Laboratory – Tim Kneafsey (TJKneafsey@lbl.gov or 510-486-4414)