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  • Journal article
    Bijeljic B, Raeini A, Mostaghimi P, Blunt MJet al., 2013,

    Predictions of non-Fickian solute transport in different classes of porous media using direct simulation on pore-scale images.

    , Phys Rev E Stat Nonlin Soft Matter Phys, Vol: 87

    We present predictions of transport through micro-CT images of porous media that include the analysis of correlation structure, velocity, and the dynamics of the evolving plume. We simulate solute transport through millimeter-sized three-dimensional images of a beadpack, a sandstone, and a carbonate, representing porous media with an increasing degree of pore-scale complexity. The Navier-Stokes equations are solved to compute the flow field and a streamline simulation approach is used to move particles by advection, while the random walk method is employed to represent diffusion. We show how the computed propagators (concentration as a function of displacement) for the beadpack, sandstone, and carbonate depend on the width of the velocity distribution. A narrow velocity distribution in the beadpack leads to the least anomalous behavior, where the propagators rapidly become Gaussian in shape; the wider velocity distribution in the sandstone gives rise to a small immobile concentration peak, and a large secondary mobile peak moving at approximately the average flow speed; in the carbonate with the widest velocity distribution, the stagnant concentration peak is persistent, with a slower emergence of a smaller secondary mobile peak, characteristic of highly anomalous behavior. This defines different types of transport in the three media and quantifies the effect of pore structure on transport. The propagators obtained by the model are in excellent agreement with those measured on similar cores in nuclear magnetic resonance experiments by Scheven, Verganelakis, Harris, Johns, and Gladden, Phys. Fluids 17, 117107 (2005).

  • Journal article
    Agar S, Geiger S, Leonide P, Lamarche J, Bertotti G, Gosselin O, Hampson GJ, Jackson MD, Jones G, Kenter J, Matthai SK, Neilson J, Pyrak-Nolte L, Whittaker Fet al., 2013,

    Summary of the AAPG–SPE–SEG Hedberg Research Conference on “Fundamental Controls on Flow in Carbonates”

    , AAPG Bulletin, Vol: 97, Pages: 533-552

    A joint AAPG–Society of Petroleum Engineers–Society of Exploration Geophysicists Hedberg Research Conference was held in Saint-Cyr sur Mer, France, on July 8 to 13, 2012, to review current research and explore future research directions related to improved production from carbonate reservoirs. Eighty-seven scientists from academia and industry (split roughly equally) attended for five days. A primary objective for the conference was to explore novel connections among different disciplines (primarily within geoscience and reservoir engineering) as a way to define new research opportunities. Research areas represented included carbonate sedimentology and stratigraphy, structural geology, geomechanics, hydrology, reactive transport modeling, seismic imaging (including four-dimensional seismic, tomography, and seismic forward modeling), geologic modeling and forward modeling of geologic processes, petrophysics, statistical methods, numerical methods for simulation, reservoir engineering, pore-scale processes, in-situ flow experiments (e.g., x-ray computed tomography), visualization, and methods for data interaction.

  • Conference paper
    Tang X, Paluszny A, Zimmerman RW, 2013,

    A Study of the Influence of Fragmentation in Ore-Pass Hang-up Phenomena

    , Publisher: American Rock Mechanics Association

    Abstract: Fragmentation strongly influences the interlocking hang-up phenomena, a common occurrence in conjunction with cohesive arching around draw points in block caving systems. This work presents a brief numerical study of the influence of fragmentation on interlocking hang-up phenomena. Fragment interaction and breakup are simulated numerically by combining the impulse-based energy tracking method (ETM) and the finite element method (FEM) in three dimensions. Numerical tests with varying size of ore fragments are carried out. The breakage of rock fragments is modeled during the entire simulation and the influence of fragmentation is investigated in terms of productivity and the efficiency of draw point extraction. Simulation results with fragmentation are compared to non-fragmentation numerical tests. It is observed that with fragmentation, 1.93% and 2.57% more volume of ore fragments are extracted before hang-up when the initial diameter of ore fragments is 5.775 m and 7.5 m, respectively.

  • Conference paper
    Nejati M, Paluszny A, Zimmerman RW, 2013,

    Theoretical and Numerical Modeling of Rock Hysteresis Based on Sliding of Microcracks

    , 47th U.S. Rock Mechanics/Geomechanics Symposium, Publisher: American Rock Mechanics Association, Pages: 573-581

    Nonlinearity and hysteresis are two key features of elastic rock deformation. This behavior can be attributed to the presence of cracks and crack-like voids. The hysteretic behavior of rocks is related to the concept of unrecovered energy. Two main processes lead to the existence of unrecovered energy in the sliding crack model: (i) the work of frictional forces and (ii) the strain energy trapped in the solid. In this paper, a theoretical and numerical analysis will be presented to extend the work of David et al. [1] to consider 3D penny-shaped cracks. A 3D finite element analysis is used to evaluate the sliding crack model numerically. In this approach, the penalty method is used to simulate the contact behavior of the crack faces. The stick-slip condition of the crack faces is simulated by employing the constitutive frictional law of Amontons. The results show that no residual strain is developed in the body containing randomly oriented cracks if one assumes a uniform stress over all the crack cells. The energy loss is therefore equal to the work of frictional forces on the crack faces.

  • Conference paper
    Latham JP, Xiang J, Anastasaki E, Vire A, Pain CCet al., 2013,

    HOW DO RUBBLE BREAKWATERS SURVIVE WAVE ATTACK? CHALLENGES FOR A FEMDEM/CFD MODEL SOLUTION

    , Colorado School of Mines, 6th International Conference on Discrete Element Methods (DEM6), Pages: 42-48, ISSN: 0010-1745

    Rubble-mound breakwaters are mainly designed using empirical equations, scaled hydraulics laboratory test models and precedent practice. Detailed understanding of the hydraulic and contact forces and stresses governing whether they survive or fail under wave action remains elusive. Numerical modeling has the potential to probe the complexity of the interacting physics of this problem. The combined finite-discrete element method is found to give remarkable insights into the behavior of the deformable granular solid skeleton and stress generation within units. Fluid-structure interaction (FSI) models are also required. Multi-body dynamics with free surface capture and numerical wave tanks (NWT) to drive and reproduce storm-wave conditions are needed. This paper discusses some of these numerical modeling challenges for coastal and ocean engineers in the context of concrete unit armoured breakwaters and highlights an approach that focusses on achieving meaningful solids representation with FEMDEM prior to coupling with an adaptive mesh CFD code, Fluidity.

  • Conference paper
    Xiang J, Latham JP, Vire A, Anastasaki E, Pain CCet al., 2013,

    NUMERICAL MODELLING OF WAVE – RUBBLE MOUNDBREAKWATER INTERACTION

    , DEM6 - International Conference on DEMs, Pages: 426-431

    Two new approaches for Fluid-Structure Interaction (FSI) are presented. One approach is the socalled the immersed body method in which the combined Finite-Discrete Element Method (FEMDEM) that deals with solids interactions is coupled to other modelling technologies e.g. CFD, interface tracking, wave models, porous media etc. Another approach is to couple FEMDEM with a new wave proxy which treats wave motion as cyclic loading. This approach is capable of simulating a representative part of a breakwater trunk at full scale.

  • Conference paper
    Guo L, Latham JP, Xiang J, Lei Qet al., 2013,

    A Numerical Investigation of Fracture Pattern and Fracture Aperture Development in Multi-layered Rock using a Combined Finite-Discrete Element Method

    , 47th US Rock Mechanics/Geomechanics Symposium, Publisher: American Rock Mechanics Association
  • Conference paper
    Karantzoulis N, Xiang J, Izzuddin B, Latham JPet al., 2013,

    NUMERICAL IMPLEMENTATION OF PLASTICITY MATERIAL MODELS IN THE COMBINED FINITE-DISCRETE ELEMENT METHOD AND VERIFICATION TESTS

    , DEM6 - International Conference on DEMs, Pages: 319-323

    Until recently the combined finite-discrete element method (FEMDEM) has been usedonly with elastic constitutive models. In this paper the implementation of plasticity in thefully three-dimensional FEMDEM code (Y3D) is discussed. After setting up the adoptedgeneral governing equations of the problem, two different numerical verification tests arepresented. Favourable results show the successful implementation and demonstrate thepotential of the developed approach.

  • Journal article
    Gharbi O, Blunt MJ, 2012,

    The impact of wettability and connectivity on relative permeability in carbonates: A pore network modeling analysis

    , WATER RESOURCES RESEARCH, Vol: 48, ISSN: 0043-1397
  • Journal article
    Blumenfeld R, Jordan JF, Edwards SF, 2012,

    Interdependence of the Volume and Stress Ensembles and Equipartition in Statistical Mechanics of Granular Systems

    , PHYSICAL REVIEW LETTERS, Vol: 109, ISSN: 0031-9007
  • Conference paper
    Mostaghimi P, Bijeljic B, Blunt MJ, 2012,

    Simulation of Flow and Dispersion on Pore-Space Images

    , SPE Annual Technical Conference and Exhibition, Publisher: SOC PETROLEUM ENG, Pages: 1131-1141, ISSN: 1086-055X
  • Journal article
    Leung CTO, Hoch AR, Zimmerman RW, 2012,

    Comparison of discrete fracture network and equivalent continuum simulations of fluid flow through two-dimensional fracture networks for the DECOVALEX-2011 project

    , MINERALOGICAL MAGAZINE, Vol: 76, Pages: 3179-3190, ISSN: 0026-461X
  • Journal article
    Umla R, Riesco N, Vesovic V, 2012,

    Viscosity of pure fluids-Enskog-2 sigma model

    , FLUID PHASE EQUILIBRIA, Vol: 334, Pages: 89-96, ISSN: 0378-3812
  • Journal article
    Viré A, Xiang J, Milthaler F, Farrell P, Piggott MD, Latham JP, Pavlidis D, Pain CCet al., 2012,

    Modelling of fluid–solid interactions using an adaptive mesh fluid model coupled with a combined finite–discrete element model

    , Ocean Dynamics
  • Journal article
    Paul JD, Blunt MJ, 2012,

    Wastewater filtration and re-use: An alternative water source for London

    , SCIENCE OF THE TOTAL ENVIRONMENT, Vol: 437, Pages: 173-184, ISSN: 0048-9697
  • Journal article
    Solano JMS, Jackson MD, Sparks RSJ, Blundy JD, Annen Cet al., 2012,

    Melt Segregation in Deep Crustal Hot Zones: a Mechanism for Chemical Differentiation, Crustal Assimilation and the Formation of Evolved Magmas

    , Journal of Petrology, Vol: 53, Pages: 1999-2026, ISSN: 1460-2415

    Mantle-derived basaltic sills emplaced in the lower crust provide amechanism for the generation of evolved magmas in deep crustal hotzones (DCHZ).This study uses numerical modelling to characterizethe time required for evolved magma formation, the depth and temperatureat which magma formation occurs, and the composition ofthe magma.The lower crust is assumed to comprise amphibolite. Inan extension of previous DCHZ models, the new model couples heattransfer during the repetitive emplacement of sills with mass transfervia buoyancy-driven melt segregation along grain boundaries.The resultsshed light on the dynamics of DCHZ development and evolution.TheDCHZ comprises a mush of crystals plus interstitial melt,except when a new influx of basaltic magma yields a short-lived(20^200 years) reservoir of melt plus suspended crystals (magma).Melt segregation and accumulation within the mush yields two contrastingmodes of evolved magma formation, which operate over timescalesof c. 10 kyr-1 Myr, depending upon emplacement rate andstyle. In one, favoured by emplacement via over-accretion, or emplacementat high rates, evolved magma forms in the crust overlying theintruded basalt sills, and is composed of crustal partial melt, and residualmelt that has migrated upwards out of the crystallizingbasalt. In the other, favoured by emplacement via under- orintra-accretion, or by emplacement at lower rates, evolved magmaforms in the intruded basalt, and the resulting magma is composedprimarily of residual melt. In all cases, the upward migration ofbuoyant melt yields cooler and more evolved magmas, which arebroadly granitic in composition. Chemical differentiation is thereforedriven by melt migration, because the melt migrates through, andchemically equilibrates with, partially molten rock at progressivelylower temperatures. Crustal assimilation occurs during partial melting,and mixing of crustal and residual melt occurs when residualmelt migrates into the partially molten crust, yielding

  • Journal article
    Sakai M, Takahashi H, Pain CC, Latham J-P, Xiang Jet al., 2012,

    Study on a large-scale discrete element model for fine particles in a fluidized bed

    , ADVANCED POWDER TECHNOLOGY, Vol: 23, Pages: 673-681, ISSN: 0921-8831
  • Journal article
    David EC, Zimmerman RW, 2012,

    Pore structure model for elastic wave velocities in fluid-saturated sandstones

    , JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, Vol: 117, ISSN: 2169-9313
  • Journal article
    Leung CTO, Zimmerman RW, 2012,

    Estimating the Hydraulic Conductivity of Two-Dimensional Fracture Networks Using Network Geometric Properties

    , TRANSPORT IN POROUS MEDIA, Vol: 93, Pages: 777-797, ISSN: 0169-3913
  • Journal article
    Elsheikh AH, Jackson MD, Laforce TC, 2012,

    Bayesian Reservoir History Matching Considering Model and Parameter Uncertainties

    , MATHEMATICAL GEOSCIENCES, Vol: 44, Pages: 515-543, ISSN: 1874-8961
  • Journal article
    Raeini AQ, Blunt MJ, Bijeljic B, 2012,

    Modelling two-phase flow in porous media at the pore scale using the volume-of-fluid method

    , JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 231, Pages: 5653-5668, ISSN: 0021-9991
  • Journal article
    Babaei M, King PR, 2012,

    A Modified Nested-Gridding for Upscaling-Downscaling in Reservoir Simulation

    , TRANSPORT IN POROUS MEDIA, Vol: 93, Pages: 753-775, ISSN: 0169-3913
  • Journal article
    David EC, Brantut N, Schubnel A, Zimmerman RWet al., 2012,

    Sliding crack model for nonlinearity and hysteresis in the uniaxial stress-strain curve of rock

    , INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, Vol: 52, Pages: 9-17, ISSN: 1365-1609
  • Journal article
    Iglauer S, Ferno MA, Shearing P, Blunt MJet al., 2012,

    Comparison of residual oil cluster size distribution, morphology and saturation in oil-wet and water-wet sandstone

    , JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 375, Pages: 187-192, ISSN: 0021-9797
  • Journal article
    Hellmann R, Bich E, Vogel E, Vesovic Vet al., 2012,

    Thermophysical Properties of Dilute Hydrogen Sulfide Gas

    , JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 57, Pages: 1312-1317, ISSN: 0021-9568
  • Journal article
    Al-Bulushi NI, King PR, Blunt MJ, Kraaijveld Met al., 2012,

    Artificial neural networks workflow and its application in the petroleum industry

    , NEURAL COMPUTING & APPLICATIONS, Vol: 21, Pages: 409-421, ISSN: 0941-0643
  • Journal article
    Blumenfeld R, Edwards SF, 2012,

    Theory of Strains in Auxetic Materials

    , JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM, Vol: 25, Pages: 565-571, ISSN: 1557-1939
  • Journal article
    Glover PWJ, Walker E, Jackson MD, 2012,

    Streaming-potential coefficient of reservoir rock: A theoretical model

    , Geophysics, Vol: 77, Pages: D17-D43, ISSN: 1942-2156

    The streaming potential is that electrical potential whichdevelops when an ionic fluid flows through the pores of a rock.It is an old concept that is recently being applied in many fieldsfrom monitoring water fronts in oil reservoirs to understandingthe mechanisms behind synthetic earthquakes. We have carriedout fundamental theoretical modeling of the streaming-potentialcoefficient as a function of pore fluid salinity, pH, and temperatureby modifying the HS equation for use with porous rocksand using input parameters from established fundamental theory(the Debye screening length, the Stern-plane potential, the zetapotential, and the surface conductance). The model also requiresthe density, electrical conductivity, relative electric permittivityand dynamic viscosity of the bulk fluid, for which empiricalmodels are used so that the temperature of the model may bevaried. These parameters are then combined with parametersthat describe the rock microstructure. The resulting theoreticalvalues have been compared with a compilation of data for siliceousmaterials comprising 290 streaming-potential coefficientmeasurements and 269 zeta-potential measurements obtainedexperimentally for 17 matrix-fluid combinations (e.g., sandstonesaturated with KCl), using data from 29 publications.The theoretical model was found to ably describe the main featuresof the data, whether taken together or on a sample by samplebasis. The low-salinity regime was found to be controlled bysurface conduction and rock microstructure, and was sensitiveto changes in porosity, cementation exponent, formation factor,grain size, pore size and pore throat size as well as specific surfaceconductivity. The high-salinity regime was found to be subjectto a zeta-potential offset that allows the streaming-potentialcoefficient to remain significant even as the saturation limit isapproached

  • Journal article
    AlSofi AM, Blunt MJ, 2012,

    A segregated flow scheme to control numerical dispersion for multi-component flow simulations

    , COMPUTATIONAL GEOSCIENCES, Vol: 16, Pages: 335-350, ISSN: 1420-0597
  • Journal article
    Sadeghnejad S, Masihi M, Shojaei A, Pishvaie M, King PRet al., 2012,

    Field Scale Characterization of Geological Formations Using Percolation Theory

    , TRANSPORT IN POROUS MEDIA, Vol: 92, Pages: 357-372, ISSN: 0169-3913

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