Temperature Dependence of the Equilibrium Pore Water Content in Gas Hydrate Contained Sediments

摘要

Analysis of sediment composition of saturated gas hydrates revealed that pore water does not completely transform into gas hydrates. The minimal possible amount of water in the sediment at fixed thermo-pressure conditions may be considered as equilibrium residual water (nonclathrated water), analogous to unfrozen water in frozen sediments. Experimental study of equilibrium for the "pore water in sediment - hydrate-forming gas - bulk gas hydrate" system allowed us to develop the technology for determination of nonclathrated water in sediments. On the basis of the proposed technique the experimental data of nonclathrated water content were obtained in different conditions. These data allow us to define the dependence of nonclathrated water content via pressure, temperatures, type of dispersed sediment, and hydrate-former (methane and carbon dioxide). A comparison of the behavior of nonclathrated water and unfrozen water is presented.