Controlled Growth of Polycrystalline Ethane Hydrate and Inferences for Gas Recovery from Hydrate Deposits

摘要

Profuse formation of hydrate shells on gas bubbles and nucleation of at least seven different morphologies or species of gas hydrate have been achieved in natural seawater. By using newly collected natural seawater, which is a chemically and biologically complex fluid, our experiments in pressurized, refrigerated vessels closely track the growth mechanisms of gas hydrate in oceanic seafloors. Nearly complete pore fill by hydrate can best be accomplished by nucleation of hydrate at point sources within the pore water or on sediment particulate, with growth outward into water space that is refreshed with circulating pore water having high concentrations of hydrate forming gas. Recovery of natural gas from hydrate deposits will depend on ensuring a large enough surface area of hydrate exposed to the circulating pore water. Fracking may be required.