Development of a simple lateral preferential flow model with steady state application in hillslope soils

Abstract. The study of water movement in soils is of fundamental importance in hydrologic science. It is generally accepted that in most soils, water and solutes flow through unsaturated zones via preferential paths or fingers. This paper combines magnetic resonance imaging (MRI) with both fractal and multifractal theory to characterize preferential flow in three dimensions. A cubic double-layer column filled with fine and coarse textured sand was placed into a 500 gauss MRI system. Water infiltration through the column (0.15×0.15×0.15 m3) was recorded in steady state conditions. Twelve sections with a voxel volume of 0.1×0.1×10 mm3 each were obtained and characterized using fractal and multifractal theory. The MRI system provided a detailed description of the preferential flow under steady state conditions and was also useful in understanding the dynamics of the formation of the fingers. The f(α) multifractal spectrum was very sensitive to the variation encountered at each horizontally-oriented slice of the column and provided a suitable characterization of the dynamics of the process identifying four spatial domains. In conclusion, MRI and fractal and multifractal analysis were able to characterize and describe the preferential flow process in soils. Used together, the two methods provide a good alternative to study flow transport phenomena in soils and in porous media.

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Numerical modelling of the historic front variation and the future behaviour of the Pasterze glacier, Austria

Annals of Glaciology ◽

10.3189/s0260305500012234 ◽

1997 ◽

Vol 24 ◽

pp. 234-241 ◽

Cited By ~ 6

Author(s):

Z. Zuo ◽

J. Oerlemans

Keyword(s):

Steady State ◽

Flow Model ◽

Calibration Method ◽

Climate Scenarios ◽

Ice Dynamics ◽

Ice Flow ◽

Steady State Condition ◽

Ice Volume ◽

Future Warming ◽

Dynamic Calibration Method

An ice-flow model is used to simulate the front variations of the Pasterze glacier, Austria. The model deals explicitly with the ice flux from sub-streams and tributaries to the main ice stream. The dynamic calibration method adopted successfully calibrates the ice-flow model under a non-steady-state condition. Despite the complexity of the glacier geometry, the ice dynamics of the Pasterze are adequately simulated.Results of the sensitivity experiments suggest that the Pasterze glacier has been in a non-steady state most of the time and has a response time of 34–50 years.Projections of the behaviour of the Pasterze in the next 100 years are made under various climate scenarios. Results suggest that the Pasterze will undergo a substantial retreat if there is future warming. The glacier is likely to retreat 2–5 km by the year 2100. The ice volume could be reduced by 24–63% by the end of the 21st century.

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Two-lane traffic-flow model with an exact steady-state solution

Physical Review E ◽

10.1103/physreve.82.066107 ◽

2010 ◽

Vol 82 (6) ◽

Cited By ~ 16

Author(s):

Masahiro Kanai

Keyword(s):

Steady State ◽

Traffic Flow ◽

Flow Model ◽

Steady State Solution ◽

State Solution ◽

Traffic Flow Model

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Prediction of mobile water in a tight gas sandstone reservoir using NMR and fractional flow model

The APPEA Journal ◽

10.1071/aj13005 ◽

2014 ◽

Vol 54 (2) ◽

pp. 1

Author(s):

Maria Anantawati ◽

Suryakant Bulgauda

Keyword(s):

Steady State ◽

Relative Permeability ◽

Flow Model ◽

Bound Water ◽

Free Water ◽

Development Project ◽

Asia Pacific ◽

Fractional Flow ◽

Reservoir Properties ◽

Mobile Water

One of the objectives of petrophysical interpretation is the estimation of the respective volumes of formation fluids. With traditional interpretation using conventional openhole logs it is only possible to determine the total amount of water. The challenge is to determine the volumes of bound water (clay-bound and capillary-bound) and free water. At the moment, NMR is the only measurement that can help distinguish the volumes of each water component (clay-bound, capillary-bound and mobile), using cut-offs on T2 (transverse relaxation time). However NMR interpretation also requires information on reservoir properties. Alternatively, steady-state relative permeability and fractional flow of water can be used to determine the potential of mobile water. The study area, located in the Cooper Basin, South Australia, is the target of a planned gas development project in the Patchawarra formation. It comprises multiple stacked fluvial sands which are heterogeneous, tight and of low deliverability. The sands are completed with multi-stage pin-point fracturing as a key enabling technology for the area. A comprehensive set of data, including conventional logs, cores and NMR logs, were acquired. Routine and special core analysis were performed, including NMR, electrical properties, centrifuge capillary pressure, high-pressure mercury injection, and full curve steady state relative permeability. A fractional flow model was built based on core and NMR data to determine potential mobile water and the results compared with production logs. This paper (SPE 165766) was prepared for presentation at the SPE Asia Pacific Oil & Gas Conference and Exhibition, held in Jakarta, Indonesia, from 22–24 October 2013.

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