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Eyvind Aker

Publications and source records attributed to Eyvind Aker.

7 recordsLinked to original sources
arXiv2001

Bulk Flow Regimes and Fractional Flow in 2D Porous Media by Numerical Simulations

We investigate a two-dimensional network simulator that model the dynamics of two-phase immiscible bulk flow where film flow can be neglected. We present a method for simulating the detailed dynamical process where the two phases are allowed to break up into bubbles, and bubbles are allowed to merge together. The notions of drainage and imbibition are not adequate to describe this process since there is no clear front between the fluids. In fact, the simulator is constructed so that one can study the behaviour of the system far from inlets and outlets, where the two fluids have been mixed together so much that all initial fronts have broken up. The simulator gives the fractional flow as a function of the saturation of each of the fluids. For the case of two fluids with equal viscosity, we classify flow regimes that are parametrized by the capillary number.

cond-mat↗
arXiv2000

Burst dynamics during drainage displacements in porous media: Simulations and experiments

We investigate the burst dynamics during drainage going from low to high injection rate at various fluid viscosities. The bursts are identified as pressure drops in the pressure signal across the system. We find that the statistical distribution of pressure drops scales according to other systems exhibiting self-organized criticality. The pressure signal was calculated by a network model that properly simulates drainage displacements. We compare our results with corresponding experiments.

cond-mat.soft↗
arXiv2000

Dynamics of stable viscous displacement in porous media

We investigate the stabilization mechanisms of the invasion front in two-dimensional drainage displacement in porous media by using a network simulator. We focus on the process when the front stabilizes due to the viscous forces in the liquids. We find that the capillary pressure difference between two different points along the front varies almost linearly as function of height separation in the direction of the displacement. The numerical results support arguments that differ from those suggested earlier for viscous stabilization. Our arguments are based upon the observation that nonwetting fluid flows in loopless strands (paths) and we conclude that earlier suggested theories are not suitable to drainage when nonwetting strands dominate the displacement process. We also show that the arguments might influence the scaling behavior between the front width and the injection rate and compare some of our results to experimental work.

physics.flu-dyn↗
arXiv2000

Viscous stabilization of 2D drainage displacements with trapping

We investigate the stabilization mechanisms due to viscous forces in the invasion front during drainage displacement in two-dimensional porous media using a network simulator. We find that in horizontal displacement the capillary pressure difference between two different points along the front varies almost linearly as function of height separation in the direction of the displacement. The numerical result supports arguments taking into account the loopless displacement pattern where nonwetting fluid flow in separate strands (paths). As a consequence, we show that existing theories developed for viscous stabilization, are not compatible with drainage when loopless strands dominate the displacement process.

physics.flu-dyn↗
arXiv1998

Simulating temporal evolution of pressure in two-phase flow in porous media

We have simulated the temporal evolution of pressure due to capillary and viscous forces in two-phase drainage in porous media. We analyze our result in light of macroscopic flow equations for two-phase flow. We also investigate the effect of the trapped clusters on the pressure evolution and on the effective permeability of the system. We find that the capillary forces play an important role during the displacements for both fast and slow injection rates and both when the invading fluid is more or less viscous than the defending fluid. The simulations are based on a network simulator modeling two-phase drainage displacements on a two-dimensional lattice of tubes.

physics.flu-dyn↗
arXiv1997

A two-dimensional network simulator for two-phase flow in porous media

We investigate a two-dimensional network simulator capable of modeling different time dependencies in two-phase drainage displacements. In particular, we focus on the temporal evolution of the pressure due to capillary and viscous forces and the time dependence of the interface between the two liquids. The dynamics of the capillary effect are taken into account and we report on high accuracy pressure measurements. Moreover, the simulator includes important features in drainage, like burst dynamics of the invading fluid and simultaneous flow of two liquids in a section of a tube. The validity of the model is checked by comparing simulation results with well known experimental properties in drainage displacement.

physics.flu-dyn↗