Elena Suetnova | Institute of Physics of the Earth, Russian Academy of Sciences (original) (raw)

Papers by Elena Suetnova

Large amounts of methane hydrate locked up within marine sediments are associated to mud volcanoe... more Large amounts of methane hydrate locked up within marine sediments are associated to mud volcanoes. We have investigated by means of mathematical modeling the unsteady process of accumulation of gas hydrates associated with the processes of mud volcanism. A mathematical model has been developed. The system of equations of the model describes the interrelated processes of filtration of gas-saturated fluid, thermal regime and pressure, and accumulation of gas hydrates in the seabed in the zone of thermobaric stability of gas hydrates. The numerical simulation of the accumulation of gas hydrates in the seabed in the deep structures of underwater mud volcanoes has been carried out using the realistic physical parameters values. The influence of the depth of the feeding reservoir and the pressure in it on the evolution of gas hydrate accumulations associated with deep-sea mud volcanoes is quantitatively analyzed. Modeling quantitatively showed that the hydrate saturation in the zones of ...

In reservoir engineering and geophysics it is important to have a fundamental understanding of ti... more In reservoir engineering and geophysics it is important to have a fundamental understanding of time dependent processes of fluid flow and species precipitation in the permeable rocks and their compaction. The porosity and effective stress evolution history of porous rock, involved into these processes, is described by a poro-viscoelastic (Maxwell-type) constitutive law. But such a process is disturbed by the precipitation and accumulations of a species in there P-T stability zones. This processes lead to decreasing of porosity and permeability. Mathematical model of coupled processes of sediment compaction and pore feeling by precipitation is developed. We formulate the coupled system of equations describing sediment accumulation and compaction, fluid and matter flow and dissolved species precipitation, and illustrate interdependence of the processes by numerical examples.

Doklady Physics, Jun 1, 1997

Automation, Telemechanization and Communication in Oil Industry, 2018

Doklady Earth Sciences, 2017

A new model that can account for accumulations of gas hydrates associated with submarine mud volc... more A new model that can account for accumulations of gas hydrates associated with submarine mud volcanoes and based on the available data on these gas hydrates is proposed. This model permits us to predict the evolution of gas-hydrate saturation by depth and time, depending on the geophysical conditions on the ocean floor in zones of mud volcanoes.

Аннотация. В статье рассмотрены процессы эволюции газогидратных скоплений приуроченных к глубоков... more Аннотация. В статье рассмотрены процессы эволюции газогидратных скоплений приуроченных к глубоководным грязевым вулканам. Представлены результаты численного моделирования аккумуляции газовых гидратов в морском дне с учетом особенностей фильтрационных процессов в глубинных структурах подводных грязевых вулканов. Количественно показана ключевая роль проницаемости слоя перекрывающего питающий резервуар грязевого вулкана. Ключевые слова: газовые гидраты, грязевые вулканы, математическое моделирование.

Tectonophysics, 1989

Abstract Data on heat flow and hydrothermal circulation near the axis of mid-oceanic ridges are c... more Abstract Data on heat flow and hydrothermal circulation near the axis of mid-oceanic ridges are considered. A statistically significant difference in mean heat flow values for a young crust of the Pacific and Atlantic oceans has been suggested. Combination of data on heat flow and hydrothermal activity of the young crust in these oceans suggests a difference in heat flow at the base of the permeable layer. A qualitative comparison of the heat flow and the character of seismicity in these regions is carried out.

Journal of Volcanology and Seismology

Вулканология и сейсмология

The article examines the processes of evolution of gas hydrate accumulations, related to submarin... more The article examines the processes of evolution of gas hydrate accumulations, related to submarine mud volcanoes. A mathematical model and the results of numerical modeling of the accumulation of gas hydrates in the seabed in the deep structures of underwater mud volcanoes are presented. Numerical analysis of the influence held feeder layer depth and pressure therein to the evolution of gas hydrate saturation confined to deep water mud volcanoes were performed. Modeling quantitatively showed that hydrate saturation in areas of underwater mud volcanoes is not constant and its evolution depends on the geophysical properties of the bottom medium (temperature gradient, porosity, permeability, physical properties of sediments) and the depth of the supply reservoir and pressure in it, and the rate of hydrate accumulation in tens and hundreds times the rate of hydrate accumulation in the sedimentary basins of passive continental margin.

Egs General Assembly Conference Abstracts, 2002

Compaction generated fluid flux and compaction of sediment is modeled in the frame of continuum m... more Compaction generated fluid flux and compaction of sediment is modeled in the frame of continuum mechanics using the effective stress principle and under the assumption of viscoelastic rheology law for the deformation of porous sediments. The effective viscosity of sediment is derived from the pressure solution equations and depends on grain size. Characteristic time of the porosity loss depends on the nondimensional group of the parameters, which includes effective viscosity and permeability of sedi- ment. Variation of physical property between accumulated sediment peel results in the formation of localized layers with different distribution of porosity and pore pressure at the basin depths. In dependence of effective viscosity, in those sediment layers over- pressure may be lower or higher than it is in the surrounding sediment. Such model result is a base to study the phenomenon of secondary migration in sedimentary basin.

Egu General Assembly Conference Abstracts, May 1, 2010

We consider the effective stress evolution inside high porosity fault zone as a result of local d... more We consider the effective stress evolution inside high porosity fault zone as a result of local dehydration due to heating. The rock is assumed to be a two-velocity medium; it consists of a deformable porous matrix (with Maxwell's rheology) and a Newtonian liquid that saturates this matrix. Nonlinear behavior of liquid saturated porous media in gravity filed under the influence of internal fluid source is modeled. The elaborated non-isothermal mathematical model is a thermodynamically consistent and closed model. The original scheme was used for computer simulation; the method implies numerical simulation for effective stress, deformation and flux time- space evolution. Deformation spreading through the saturated porous matrix occurs with pressure distortions. Calculations show that the peculiarity of effective stress evolution is dependent not only upon the volume of supplementary fluids, but upon the viscosity and elastic modules of matrix.

Sedimentation and sediment compaction are the most important processes, which determined the stru... more Sedimentation and sediment compaction are the most important processes, which determined the structure of sedimentary basins fill, stress field and physical property of basin fill on the different time and space scale. Pore pressure evolution is determined by the sedimentation rate and physical and hydro dynamical property of sediments. Effective stress evolution during sediment compaction leads to decreasing of void space and fluid content in sediment. In present work we have studied porosity reduction and fluid pressure development resulting from the visco-elastic compaction of layered sediments during its accumulation and burying. Mathematical model consists of the system of partial differential equations which includes continuity equations, Darcy's law and a visco-elastic rheology law which relates the strain rate to the effective stress and to the rate of change of this effective stress. Under the assumption that permeability is a power law function of porosity, the equations become essentially non-linear. Based on the model calculations, the effect of variations in the physical properties of the sediments on the evolution of the porosity and pore pressure accompanied by compaction of the sediments was examined. Calculations with parameters that lie within the range of the available geophysical data showed that, during basin formation, the accumulation of sedimentary layers with a permeability or viscosity differing from that of the main basin fill can substantially disturbs the monotonic porosity decrease with depth and lead to the formation, deep within the basin, of layers that have a different level of over hydrostatic pressure as compared with the surrounding layers. Similar influence can make gas hydrate which may form a barrier for fluid migration.

Agu Fall Meeting Abstracts, Dec 1, 2005

In reservoir engineering and tectonic, it is important to have a fundamental understanding of com... more 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.

Izv Phys Solid Earth, 2010

The problem of compaction of depositing sediments is studied for different geophysical characteri... more The problem of compaction of depositing sediments is studied for different geophysical characteristics of the process of sedimentation. A model is proposed for describing the compaction of sediments with growing thickness. The model is based on the modern concepts of the viscoelastic rheology of accumulating sediments; and, in terms of mathematics, it is a system of nonlinear differential equations in partial derivatives, which describe the processes of compaction and filtration with an increasing thickness of sediments. I have studied numerically the dependence of the regimes of compaction on the formulated characteristic criteria of similarity in the system of equations. Fluid-dynamic criterion, which characterizes the ratio of the rate of sedimentation to the rate of the filtration of a fluid (the rate of fluidization), and the rheological criterion of compaction, which characterizes the proportion between the viscous and elastic strains on the time scale of the process of compaction, i.e., the ratio of the two time scales—the time scale of the elastic strains’ relaxation and the time scale of the viscous compaction. The complex modeling of the mechanics and hydrodynamics of the interrelated processes of compaction and movement to the surface of the saturating fluids with an increase in the thickness of sediments reproduces the mechanism of the formation of different regimes of compaction, including those, which lead to an anomalously high pore pressure and to significant, in some circumstances step-like rise in the pressure of the saturating fluid, frequently observed at depths of 2-3 km.

Recent studies of fluid saturated sedimentary rocks suggest time-dependent component of there def... more Recent studies of fluid saturated sedimentary rocks suggest time-dependent component of there deformation. At the basin scale such mechanism of deformation is modelled in the frame of continuum mechanics using the effective stress principle and under the assumption of viscoelastic rheology law for the saturated sedimentary rosks. The effective viscosity of sediment is derived from the pressure solution equations and depends on grain size. Characteristic time of deformation depends on the nondimentional groups of the parameters, which include effective viscosity and permeability of sediment and loading rate. Diagenetic alteration will modify the transport properties of sedimentary rocks. The first-order dehydration reaction equations were introduced into the model to study the influence of diagenesis on anelastic behaviour of sedimentary rocks under the loading. The coupled nonlinear model equations have been solved numerically. The comparison of the obtained results shows that the accounting for diagenesis affects the resulting deformation of rock under wide range of applied loading rate. Such model results show how the peculiarity of an anelastic behaviour of saturated rocks are determened by there transport properties.

Porosity reduction and fluid pressure development resulting from the compaction of sediments duri... more Porosity reduction and fluid pressure development resulting from the compaction of sediments during its accumulation and burying depends on fluid transport properties of sediments. But on the other hand, permeability of sediments depends on its porosity. Our numerical modeling of the sediment compaction process shows the evolution of the permeability in time and space. Calculations show that the rate of permeability reduction depends on the rheological property of sediments, that is, of the sediment viscosity and pore compressibility. Based on the model calculations, the effect of variations of the physical properties of the sediments on the evolution of the sediment permeability, porosity and pore pressure accompanying the compaction of the sediments was examined.