Compaction in Media with Inner Boundaries and Application to Oil- Gas Geophysics Problems Subject Compaction is mechanics of porous saturated media with viscous deformed matrix or dynamics poroviscous media. These processes include the viscous deformation of a two-phase medium, percolation of a fluid through the viscous matrix and attendant chemical and physicochemical transformations of matrix and fluid, which can be multiphase and multicomponent. Position of compaction is shown on the diagram.

Position of compaction – poroviscous media Heterogeneous media Disperse media Gas disperse media Liquid disperse media Porous media Porous deformed media Porous media with rigid matrix FogsAerosols EmulsionsSuspensions Poroviscous media Poroelastic media Isolated pores Connected pores Porous media with complicated rheology With multiphase fluid

References Karakin A. V. Derivation of Main Equations Governing the Mechanics of Melting Ice. Physics of Ice and the Ice Technology. Yakutsk: Yakutsk Subdivision of Siberian Affiliated Branch of the USSR Academy. 1974, pp (in Russian). Karakin A.V., Lobkovsky L.I. Mechanics of porous two phase viscous-deformed medium and its geophysical applications // Letters Applied Engineering Science, 1979, v. 17, p (in English). McKenzie D. The generation and compaction of partially molten rock. J Petrol. 25, pp ,1984 (in English).. Karakin A.V. The General Theory of Compaction at a Small Porosity. Izvestia, Physics of the Solid Earth. Vol.35, No. 12, 1999, pp (in English). Karakin A. V. Compaction in Media with Inner Boundaries // Online journal. Russian Journal of Earth Science V. 4, # 5. P (in English). Karakin A.V., Karakin C.A. A Fluid-Dynamic Model of Mud Volcanism of the Intracontinental Type. Report of Russian Science Academy vol No. 5, pp (in Russian). Karakin A. V. Compaction with Multiphase Fluid. Izvestia, Physics of the Solid Earth. Vol.41, No. 9, 2005, pp (in English).

Compaction can take place in liquefied grounds, marshes, silts, running sands and in numerous technological processes involving liquid and paste-like mixes and colloid solutions, whenever both low- and high-viscosity phases are present. Such mixes are used in the chemical, petrochemical, biochemical and food- processing industries involving their mixing and processing. Similar processes can arise during the movement of liquid multiphase mixes through pipelines.

Gigantic tailings ponds form during the development of bituminous sands with the help of solutions containing surfactants. These ponds contain colloid solutions of hydrocarbons that are difficult to be recultivated. Sedimentation and consolidation of colloidal structures in the ponds are lasting for decades. Ecological problems restrict the potential of bitumen extraction with the help of such technologies. Colloidal structures form a coherent skeleton through which water flows.

Poroviscous medium with isolated pores Poroviscous medium with connected pores Suspension Sedimentation and consolidation processes in vessel with impermeable bottom

Sedimentation and consolidation processes in vessel with permeable bottom

Compaction equation

1. As distinct from equations of fluid hydrodynamics, elasticity, poroelasticity and dynamics of suspensions, compaction equations of motion contain the intrinsic length of compaction 2. Basic equations of compaction are essentially nonlinear. Feature of compaction

Material functions for viscosity and permeability Hydraulic resistance

External boundaries Internal boundaries (balance equations) Initial condition at

Internal boundaries (arising and dissociation of matrix) Internal boundaries (opening and closing of pores)

1-D model Dimensionless form

The geological model of Bazhen oil-bearing formation

Scheme of geological model

Arising of compaction in zones I and II

Model of concretion The plane models describing the submerging processes of solids in marshes, silts, running sands are considered. The bodies can be continuous or porous. These models discover the paradox of iron-manganese concretion. Dense concretion does not dive in light silt. Tree trunks dive in running sands. The plane model can be investigated with method of complex variable. This method assumes an analytical solution.

Continuous circle in poroviscous medium Arrows denote stream line

Porous circle in poroviscous medium Light solid colloid pillow upholds the concretion afloat

The main result of this model Moving colloid particles change the filtration conditions. They can choke up the porous space and change the Darcy's law. As a result heavy porous concretions float on a silt because of under them there is a light colloid pillow. A light tree stick dives. Under it poroviscous medium transforms into suspension. A stick dives in water phase because of it is tighter than water.

Consequence from this model We can rule the interaction between solid and poroviscous medium. The solid body can dive or surface as a submarine. It can be used in the technological processes of building pipelines, drilling platforms and another submerged works. There is a principal possibility to design a submarine to float into silt. Its movement will be very slow and it will spend very much energy.

Movement of a Mud Mixture through a Mud Volcano Channel The movement of a mud mixture through a vertical volcanic channel is studied. The mud mixture is described by a poro- viscous medium. As the mud mixture moves through a vertical cylindrical channel, friction against the channel walls produces a shear flow resembling the Poiseuille flow of an incompressible liquid in a pipe. The problem reduces to a 1-D compaction model, which is studied by numerical methods. The analysis of the solutions has led to some conclusions on the mud mixture movement. The study of the mud volcano dynamics provides important constraints on the fluid migration pattern during the formation of oil and gas deposits. Mud volcanoes are aborted deposits of oil and gas. They arise when fractures or faults appear in the domes of anticlinal traps.

Mud Volcano Model “Physics of Earth" № 10. С (in Russian ) English translation: Karakin A.V., Karakin C.A., Kambarova G.N. Movement of a Mud Mixture through a Mud Volcano Channel. Izvestia, Physics of the Solid Earth. Vol.37, No. 10, 2001, pp (in English)..

The Wave Regime in a Magma Floating up under Mid-Ocean Ridges The magma migration in ascending mantle flows is calculated in zones of partial melting. The oceanic crust forms during the spreading process involving the solidification of a magma chamber about 6 km thick at the spreading axis; this chamber accumulates the melt of low-melting components from the underlying asthenosphere zone 60 km thick. This lower-density melt rises, rapidly migrating through a slowly ascending high-viscosity matrix of the basic mantle material. The melt ascent is accompanied by a viscous deformation of the matrix. The heavier viscous matrix, being unable to support its weight, expels the light melt upward, flows into the volume left by the latter, and moves apart in the path of the melt. This process is described by the compaction equations. The axial and peripheral zones of the ascending flow are examined with the help of numerical experiments. Two possible regimes of the melt ascent analyzed are the regime of uniform stationary percolation and the oscillatory regime with compaction waves. The compaction waves can arise only in peripheral parts of the partial melting zone. Therefore, the observed chemical heterogeneity of the oceanic crust can be due to the melt that ascends off the axial ridge zone and subsequently accumulates in the magma chamber. Publication: “Physics of Earth" № 3. С (in Russian). English translation: V. P. Trubitsyn, A. V. Karakin, and S. A. Karakin. Physics of the Solid Earth. Vol.39, No. 3, 2003, pp (in English).

Ascending mantle flows under oceanic lithosphere