1 research outputs found
High-Pressure Rheology of Hydrate Slurries Formed from Water-in-Oil Emulsions
A unique high-pressure rheology apparatus is used to
study the <i>in situ</i> formation and flow properties of
gas hydrates from
a water-in-crude oil emulsion. Viscosity and pressure of the hydrate
slurry are measured during hydrate formation, growth, aggregation,
and dissociation. The rheology of the hydrate slurries varies with
time, shear rate (1–500 s<sup>–1</sup>), water content
(0–50%), and temperature (0–6 °C). Hydrate slurry
viscosity increases rapidly with time when hydrates form and then
decays after going through a maximum as hydrate aggregates breakup
or rearrange. Yield stress increases with annealing time up to 8 h
and then remains constant. Hydrate slurry viscosity decreases with
an increasing shear rate (i.e., they are shear thinning). Viscosity
and yield stress both increase with an increasing water content. During
dissociation, the viscosity increases just before the hydrate equilibrium
temperature. Finally, transient viscosity measurements at varying
temperatures suggest that mechanisms, such as cohesion forces and
shear forces, competitively affect hydrate slurry viscosity