查看文章

The small‐strain mechanical properties (e.g., seismic velocities) of hydrate‐bearing sediments measured under laboratory conditions provide reference values for calibration of logging and seismic exploration results acquired in hydrate‐bearing formations. Instrumented cells were designed for measuring the compressional (P) and shear (S) velocities of sand, silts, and clay with and without hydrate and subject to vertical effective stresses of 0.01 to 2 MPa. Tetrahydrofuran (THF), which is fully miscible in water, was used as the hydrate former to permit close control over the hydrate saturation S_hyd and to produce hydrate from dissolved phase, as methane hydrate forms in most natural marine settings. The results demonstrate that laboratory hydrate formation technique controls the pattern of P and S velocity changes with increasing S_hyd and that the small‐strain properties of hydrate‐bearing sediments are governed …