HR: 0800h
AN: C11A-1063    [Abstracts]
TI: Compaction Processes in Porous Glaciogenic Sediment.
AU: * Suetnova, E I
EM: elena@ifz.ru
AB: In reservoir engineering and tectonic, it is important to have a fundamental understanding of compaction. Gas-hydrate accumulation and melting are the important processes which could disturb the normal compaction process. Pervasive pressure solution transfer describes permanent porosity reduction in stressed porous aggregates saturated by an aqueous solution. This process includes dissolution of the grain contacts due to stress-enhanced solubility, solute transport by diffusion along the grain contacts, and precipitation of the solute on the free faces of the grains. Pressure solution transfer corresponds to a response of the aggregate in an attempt to increase the grain-to-grain contiguity so as to redistribute the local effective stress over a larger grain-to-grain contact area. The porosity and effective stress evolution during geological history of porous rock is described by a poro-visco-elastic (Maxwell-type) constitutive law. But such a process is disturbed by gas hydrate accumulations in the hydrate stability zone due to gas leakages. Accumulations of hydrate in the hydrate stability zone leads to decreasing of porosity and permeability. Mathematical model of coupled processes of sediment compaction and gas-hydrate accumulations is developed. The solutions for compaction in a range of parameters that is representative of porous glaciogenic rock show that compaction process is slower than that without hydrate accumulations. Calculations show that rate of compaction is increased by melting of hydrate caused by the increasing the temperature.
DE: 1823 Frozen ground
DE: 1847 Modeling
SC: Cryosphere [C]
MN: Fall Meeting 2005