Skip to main content
U.S. flag

An official website of the United States government

Compression behavior of hydrate-bearing sediments

May 6, 2022

This work experimentally explores porosity, compressibility, and the ratio of horizontal to vertical effective stress (K0) in hydrate-bearing sandy silts from Green Canyon Block 955 in the deep-water Gulf of Mexico. The samples have an in situ porosity of 0.38 to 0.40 and a hydrate saturation of more than 80%. The hydrate-bearing sediments are stiffer than the equivalent hydrate-free sediments; the K0 stress ratio is greater for hydrate-bearing sediments relative to the equivalent hydrate-free sediments. The porosity decreases by 0.01 to 0.02 when the hydrate is dissociated at the in situ effective stress. We interpret that the hydrate in the sediment pores is a viscoelastic material that behaves like a fluid over experimental time scales, yet it cannot escape the sediment skeleton. During compression, the hydrate bears a significant fraction of the applied vertical load and transfers this load laterally, resulting in the apparent increased stiffness and a larger apparent K0 stress ratio. When dissociation occurs, the load carried by the hydrate is transferred to the sediment skeleton, resulting in further compaction and a decrease in the lateral stress. The viewpoint that the hydrate is a trapped viscous phase provides a mechanism for how stiffness and stress ratio (K0) are greater when hydrate is present in the porous media. This study provides insight into the initial stress state of hydrate-bearing reservoirs and the geomechanical evolution of these reservoirs during production.

Publication Year 2022
Title Compression behavior of hydrate-bearing sediments
DOI 10.1306/01132221002
Authors Yi Fang, Peter Flemings, John Germaine, Hugh Daigle, Stephen C. Phillips, Joshua O'Connell
Publication Type Article
Publication Subtype Journal Article
Series Title AAPG Bulletin
Index ID 70231315
Record Source USGS Publications Warehouse
USGS Organization Woods Hole Coastal and Marine Science Center