Kirby S. H.

No Thumbnail Available
Last Name
Kirby
First Name
S. H.
ORCID

Search Results

Now showing 1 - 3 of 3
Thumbnail Image
Article

Simultaneous determination of thermal conductivity, thermal diffusivity and specific heat in sI methane hydrate

2007-03-11 , Waite, William F. , Stern, Laura A. , Kirby, S. H. , Winters, William J. , Mason, D. H.

Thermal conductivity, thermal diffusivity and specific heat of sI methane hydrate were measured as functions of temperature and pressure using a needle probe technique. The temperature dependence was measured between −20°C and 17°C at 31.5 MPa. The pressure dependence was measured between 31.5 and 102 MPa at 14.4°C. Only weak temperature and pressure dependencies were observed. Methane hydrate thermal conductivity differs from that of water by less than 10 per cent, too little to provide a sensitive measure of hydrate content in water-saturated systems. Thermal diffusivity of methane hydrate is more than twice that of water, however, and its specific heat is about half that of water. Thus, when drilling into or through hydrate-rich sediment, heat from the borehole can raise the formation temperature more than 20 per cent faster than if the formation's pore space contains only water. Thermal properties of methane hydrate should be considered in safety and economic assessments of hydrate-bearing sediment.

Thumbnail Image
Article

Elastic wave speeds and moduli in polycrystalline ice Ih, sI methane hydrate, and sII methane-ethane hydrate

2009-02-27 , Helgerud, M. B. , Waite, William F. , Kirby, S. H. , Nur, A.

We used ultrasonic pulse transmission to measure compressional, P, and shear, S, wave speeds in laboratory-formed polycrystalline ice Ih, sI methane hydrate, and sII methane-ethane hydrate. From the wave speed's linear dependence on temperature and pressure and from the sample's calculated density, we derived expressions for bulk, shear, and compressional wave moduli and Poisson's ratio from −20 to −5°C and 22.4 to 32.8 MPa for ice Ih, −20 to 15°C and 30.5 to 97.7 MPa for sI methane hydrate, and −20 to 10°C and 30.5 to 91.6 MPa for sII methane-ethane hydrate. All three materials had comparable P and S wave speeds and decreasing shear wave speeds with increasing applied pressure. Each material also showed evidence of rapid intergranular bonding, with a corresponding increase in wave speed, in response to pauses in sample deformation. There were also key differences. Resistance to uniaxial compaction, indicated by the pressure required to compact initially porous samples, was significantly lower for ice Ih than for either hydrate. The ice Ih shear modulus decreased with increasing pressure, in contrast to the increase measured in both hydrates.

Thumbnail Image
Article

Correction to “Elastic wave speeds and moduli in polycrystalline ice Ih, sI methane hydrate, and sII methane-ethane hydrate”

2009-04-10 , Helgerud, M. B. , Waite, William F. , Kirby, S. H. , Nur, A.