scholarly journals Retention of Nanoparticles: From Laboratory Cores to Outcrop Scale

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Harpreet Singh ◽  
Farzam Javadpour
Keyword(s):  
Porous Media ◽  
Laboratory Experiments ◽  
Multiple Scales ◽  
Homogeneous Medium ◽  
Laboratory Scale ◽  
Small Scale ◽  
Length Scale ◽  
The Media ◽  
Small Change ◽  
Homogeneous Media

Laboratory experiments on small scale core plugs have shown controlled nanoparticles (NPs) retention. The length scale of subsurface media where NPs must be transported is an important factor that should be accounted for in a comprehensive manner when translating laboratory results to field scale. This study investigates the fraction of NPs retained inside porous media as a function of length scale of the media. A two-dimensional numerical model was used to simulate the retention of NPs at multiple scales of porous media, starting from laboratory scale cores to heterogeneous outcrop scales. Retention of NPs is modeled based on the concept of reversible and irreversible retention, by using the laboratory scale determined parameters. Our results show that the fraction of retained NPs increases nonlinearly with the length scale of the homogeneous media. The results also show that if the heterogeneity of the medium is consistent across scales, the fraction of retained NPs would behave just like homogeneous medium. In this study, small change in heterogeneity at two outcrop scales affects the retention of NPs, suggesting that heterogeneity may significantly impact the retention behavior of NPs that may not necessarily follow the behavior predicted from homogeneous cores (or periodically heterogeneous medium).

Sound Attenuation in Heterogeneous Porous Media Due to Viscous Effects

2003 ◽  
Author(s):  
A. Vadnjal ◽  
I. Catton
Keyword(s):  
Porous Media ◽  
Wave Propagation ◽  
Volume Averaging ◽  
Heterogeneous Porous Media ◽  
Governing Equations ◽  
Viscous Effects ◽  
One Dimensional ◽  
Media Comparison ◽  
The Media ◽  
Homogeneous Media

Volume averaging theory (VAT) is used to develop acoustic governing equations and consistent closure for one dimensional wave propagation in a heterogeneous porous media. These equations are based on continuum mechanics and scaled to delineate the parameters governing wave propagation in the media. The parameters can be evaluated for different media and be the basis for calculation of the performance of a given porous media. Comparison with experimental data are made and the comparison is very good. More general closure parameters will require experimental measurement to give appropriate models of non-homogeneous, media.

Modelling of Solute Transfer to Surface Runoff

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1851-1856 ◽  
Author(s):  
J. L. Lai ◽  
K. S. L. Lo
Keyword(s):  
Potassium Chloride ◽  
Surface Runoff ◽  
Laboratory Experiments ◽  
Overland Flow ◽  
Chloride Concentration ◽  
Runoff Water ◽  
Mixing Depth ◽  
Change Rate ◽  
Solute Transfer ◽  
The Media

A mixing-based model for describing solute transfer to overland flow was developed. This model included a time-dependent mixing depth of the top layer and a complete-mixed surface runoff zone. In a series of laboratory experiments, runoff was passed at various velocities and depths over a medium bed. The media were saturated with uniform concentration of potassium chloride solution. Runoff water was sampled at the beginning and end of the flume and the potassium chloride concentration analyzed. Using this model, dimensionless ultimate mixing depth and dimensionless change rate of mixing depth from experimental data were investigated and implemented. The results showed that the Reynolds number and relative roughness are two important factors.

The Role of Porous Media in Homogenization of High Pressure Diesel Fuel Spray Combustion

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Navid Shahangian ◽  
Damon Honnery ◽  
Jamil Ghojel
Keyword(s):  
High Pressure ◽  
Porous Media ◽  
High Speed ◽  
Fuel Spray ◽  
Compression Ignition Engines ◽  
System Pressure ◽  
Novel Approach ◽  
Air Mixing ◽  
The Media

Interest is growing in the benefits of homogeneous charge compression ignition engines. In this paper, we investigate a novel approach to the development of a homogenous charge-like environment through the use of porous media. The primary purpose of the media is to enhance the spread as well as the evaporation process of the high pressure fuel spray to achieve charge homogenization. In this paper, we show through high speed visualizations of both cold and hot spray events, how porous media interactions can give rise to greater fuel air mixing and what role system pressure and temperature plays in further enhancing this process.

Small change: individual farm work and collective life in a western Nigerian savanna town, 1969–88

Africa ◽  
1992 ◽  
Vol 62 (4) ◽  
pp. 465-489 ◽  
Author(s):  
Jane I. Guyer
Keyword(s):  
Farming System ◽  
Farm Size ◽  
Small Scale ◽  
Cropping Patterns ◽  
Farm Work ◽  
Small Change ◽  
Returns To Labour ◽  
Individual Farm ◽  
Ceremonial Life ◽  
Nigerian Savanna

AbstractA comparison of data collected in western Nigeria (the Yoruba area) in 1968-69 and 1988 suggests that small-scale male farmers' patterns of work remained quite similar in the total amount of work they did and in the amount by task. This finding seemed surprising, since the study area lies in the food supply hinterland of the rapidly growing cities of Ibadan, Lagos and Abeokuta. The farming system has changed in several ways in response to increased urban demand and improved transport, including an increase in farm size on the part of male farmers. Changed cropping patterns, the increased use of hired labour and somewhat increased returns to labour seem only partly to account for the persistence. Analysis of the work data in terms of its timing, rather than in terms of time, suggests that farmers are tending to work at the same task in longer stretches ofconsecutive days, and this, in turn, is related to the marked rescheduling of traditional ceremonial life and the intensified politico-associational life moved to the weekend.

Laboratory Experiments of Mass Transfer in the London Clay

1988 ◽  
Vol 127 ◽  
Author(s):  
P. J. Bourke ◽  
D. Gilling ◽  
N. L. Jefferies ◽  
D. A. Lever ◽  
T. R. Lineham
Keyword(s):  
Mass Transfer ◽  
Porous Media ◽  
Radioactive Waste ◽  
Mass Transport ◽  
Mathematical Models ◽  
Laboratory Experiments ◽  
Naturally Occurring ◽  
Diffusion And Convection ◽  
Waste Repository ◽  
London Clay

ABSTRACTAqueous phase mass transfer through the rocks surrounding a radioactive waste repository will take place by diffusion and convection. This paper presents a comprehensive set of measurements of the mass transfer characteristics for a single, naturally occurring, clay. These data have been compared with the results predicted by mathematical models of mass transport in porous media, in order to build confidence in these models.

Modeling of filtration processes in periodic porous media

2021 ◽  
pp. 90-93
Author(s):  
Gennadiy Sandrakov ◽  
Andrii Hulianytskyi ◽  
Vladimir Semenov
Keyword(s):  
Porous Media ◽  
Parabolic Equations ◽  
Initial Boundary ◽  
Dynamic Processes ◽  
Low Permeability ◽  
Initial Boundary Value Problems ◽  
High Permeability ◽  
Guaranteed Accuracy ◽  
The Media ◽  
Initial Boundary Value

Modeling of dynamic processes of diffusion and filtration of liquids in porous media are discussed. The media are formed by a large number of blocks with low permeability, and separated by a connected system of faults with high permeability. The modeling is based on solving initial boundary value problems for parabolic equations of diffusion and filtration in porous media. The structure of the media leads to the dependence of the equations on a small parameter. Assertions on the solvability and regularity of such problems and the corresponding homogenized convolution problems are considered. The statements are actual for the numerical solution of this problem with guaranteed accuracy that is necessary to model the considered processes.

Geomechanical and Fracture Network Interpretation of a Devonian Outcrop

2021 ◽  
pp. 1-16
Author(s):  
Scott McKean ◽  
Simon Poirier ◽  
Henry Galvis-Portilla ◽  
Marco Venieri ◽  
Jeffrey A. Priest ◽  
...  
Keyword(s):  
Large Scale ◽  
Multiple Scales ◽  
Fracture Network ◽  
Natural Fracture ◽  
Small Scale ◽  
Nugget Effect ◽  
Schmidt Hammer ◽  
Unconventional Reservoir ◽  
Fracture Anisotropy ◽  
Fracture Intensity

Summary The Duvernay Formation is an unconventional reservoir characterized by induced seismicity and fluid migration, with natural fractures likely contributing to both cases. An alpine outcrop of the Perdrix and Flume formations, correlative with the subsurface Duvernay and Waterways formations, was investigated to characterize natural fracture networks. A semiautomated image-segmentation and fracture analysis was applied to orthomosaics generated from a photogrammetric survey to assess small- and large-scale fracture intensity and rock mass heterogeneity. The study also included manual scanlines, fracture windows, and Schmidt hammer measurements. The Perdrix section transitions from brittle fractures to en echelon fractures and shear-damage zones. Multiple scales of fractures were observed, including unconfined, bedbound fractures, and fold-relatedbed-parallel partings (BPPs). Variograms indicate a significant nugget effect along with fracture anisotropy. Schmidt hammer results lack correlation with fracture intensity. The Flume pavements exhibit a regionally extensive perpendicular joint set, tectonically driven fracturing, and multiple fault-damage zones with subvertical fractures dominating. Similar to the Perdrix, variograms show a significant nugget effect, highlighting fracture anisotropy. The results from this study suggest that small-scale fractures are inherently stochastic and that fractures observed at core scale should not be extrapolated to represent large-scale fracture systems; instead, the effects of small-scale fractures are best represented using an effective continuum approach. In contrast, large-scale fractures are more predictable according to structural setting and should be characterized robustly using geological principles. This study is especially applicable for operators and regulators in the Duvernay and similar formations where unconventional reservoir units abut carbonate formations.

Sign in / Sign up

Export Citation Format

Share Document