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  • Journal article
    Iglauer S, Paluszny A, Blunt MJ, 2015,

    Simultaneous oil recovery and residual gas storage: A pore-level analysis using in situ X-ray micro-tomography (vol 103, pg 905, 2013)

    , FUEL, Vol: 139, Pages: 780-780, ISSN: 0016-2361
  • Journal article
    AlSofi AM, Blunt MJ, 2014,

    Polymer flooding design and optimization under economic uncertainty

    , JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING, Vol: 124, Pages: 46-59, ISSN: 0920-4105
  • Journal article
    Raeini AQ, Blunt MJ, Bijeljic B, 2014,

    Direct simulations of two-phase flow on micro-CT images of porous media and upscaling of pore-scale forces

    , Advances in Water Resources, Vol: 74, Pages: 116-126, ISSN: 0309-1708

    Pore-scale forces have a significant effect on the macroscopic behaviour of multiphase flow through porous media. This paper studies the effect of these forces using a new volume-of-fluid based finite volume method developed for simulating two-phase flow directly on micro-CT images of porous media. An analytical analysis of the relationship between the pore-scale forces and the Darcy-scale pressure drops is presented. We use this analysis to propose unambiguous definitions of Darcy-scale viscous pressure drops as the rate of energy dissipation per unit flow rate of each phase, and then use them to obtain the relative permeability curves. We show that this definition is consistent with conventional laboratory/field measurements by comparing our predictions with experimental relative permeability. We present single and two-phase flow simulations for primary oil injection followed by water injection on a sandpack and a Berea sandstone. The two-phase flow simulations are presented at different capillary numbers which cover the transition from capillary fingering at low capillary numbers to a more viscous fingering displacement pattern at higher capillary numbers, and the effect of capillary number on the relative permeability curves is investigated. Overall, this paper presents a new finite volume-based methodology for the detailed analysis of two-phase flow directly on micro-CT images of porous media and upscaling of the results to the Darcy scale.

  • Journal article
    Singh G, Zimmerman RW, 2014,

    Modification of Griffith-McClintock-Walsh model for crack growth under compression to incorporate stick-slip along the crack faces

  • Journal article
    Siavashi M, Blunt MJ, Raisee M, Pourafshary Pet al., 2014,

    Three-dimensional streamline-based simulation of non-isothermal two-phase flow in heterogeneous porous media

    , COMPUTERS & FLUIDS, Vol: 103, Pages: 116-131, ISSN: 0045-7930
  • Journal article
    Al-Hadhrami MM, Alkindi AS, Muggeridge AH, 2014,

    Experimental and numerical investigations into the effect of heterogeneities on the recovery of heavy oil by VAPour EXtraction (VAPEX)

    , FUEL, Vol: 135, Pages: 413-426, ISSN: 0016-2361
  • Journal article
    Andrew M, Bijeljic B, Blunt MJ, 2014,

    Pore-by-pore capillary pressure measurements using X-ray microtomography at reservoir conditions: Curvature, snap-off, and remobilization of residual CO2

    , WATER RESOURCES RESEARCH, Vol: 50, Pages: 8760-8774, ISSN: 0043-1397
  • Journal article
    Blumenfeld R, Edwards SF, 2014,

    Granular statistical mechanics - a personal perspective

    , EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS, Vol: 223, Pages: 2189-2204, ISSN: 1951-6355
  • Journal article
    Petvipusit KR, Elsheikh AH, Laforce TC, King PR, Blunt MJet al., 2014,

    Robust optimisation of CO2 sequestration strategies under geological uncertainty using adaptive sparse grid surrogates

    , COMPUTATIONAL GEOSCIENCES, Vol: 18, Pages: 763-778, ISSN: 1420-0597
  • Journal article
    Kang PK, de Anna P, Nunes JP, Bijeljic B, Blunt MJ, Juanes Ret al., 2014,

    Pore-scale intermittent velocity structure underpinning anomalous transport through 3-D porous media

    , GEOPHYSICAL RESEARCH LETTERS, Vol: 41, Pages: 6184-6190, ISSN: 0094-8276
  • Journal article
    Singh G, Kermode JR, De Vita A, Zimmerman RWet al., 2014,

    Validity of linear elasticity in the crack-tip region of ideal brittle solids

    , INTERNATIONAL JOURNAL OF FRACTURE, Vol: 189, Pages: 103-110, ISSN: 0376-9429
  • Journal article
    Leinov E, Jackson MD, 2014,

    Experimental measurements of the SP response to concentration and temperature gradients in sandstones with application to subsurface geophysical monitoring

    , JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, Vol: 119, Pages: 6855-6876, ISSN: 2169-9313
  • Journal article
    Lei Q, Latham J-P, Xiang J, Tsang C-F, Lang P, Guo Let al., 2014,

    Effects of geomechanical changes on the validity of a discrete fracture network representation of a realistic two-dimensional fractured rock

    , International Journal of Rock Mechanics and Mining Sciences, Vol: 70, Pages: 507-523, ISSN: 0020-7624

    This paper aims to examine the validity of the discrete fracture network (DFN) method in representing a realistic two-dimensional fractured rock in terms of their geomechanical response to in-situ stresses and hydraulic behaviour in a steady state fluid field. First, a real fracture network is extracted from the geological map of an actual rock outcrop, which is termed the analogue fracture network (AFN). Multiple DFN realisations are created using the statistics of the analogue pattern. A conductivity parameter that was found to have a linear relationship with the conductivity of 2D fracture networks is included to further enhance network similarity. A series of numerical experiments are designed with far-field stresses applied at a range of angles to the rock domains and their geomechanical response is modelled using the combined finite-discrete element method (FEMDEM). A geomechanical comparison between the AFN and its DFN equivalents is made based on phenomena such as heterogeneity of fracture-dependent stress contours, sliding between pre-existing fracture walls, coalescence of propagating fractures and variability of aperture distribution. Furthermore, an indirect hydro-mechanical (HM) coupling is applied and the hydraulic behaviour of the porous rock models is investigated using the hybrid finite element-finite volume method (FEFVM). A further comparison is conducted focusing on the hydraulic behaviour of the AFN and DFNs under the effects of geomechanical changes. The results show that although DFNs may represent an AFN quite well for fixed mechanical conditions, such a representation may not be dependable if mechanical changes occur.

  • Journal article
    Siena M, Guadagnini A, Riva M, Bijeljic B, Pereira Nunes JP, Blunt MJet al., 2014,

    Statistical scaling of pore-scale Lagrangian velocities in natural porous media

    , PHYSICAL REVIEW E, Vol: 90, ISSN: 1539-3755
  • Journal article
    Lang PS, Paluszny A, Zimmerman RW, 2014,

    Permeability tensor of three-dimensional fractured porous rock and a comparison to trace map predictions

    , Journal of Geophysical Research: Solid Earth, Vol: 119, Pages: 6288-6307, ISSN: 2169-9356

    The reduction from three‐ to two‐dimensional analysis of the permeability of a fractured rock mass introduces errors in both the magnitude and direction of principal permeabilities. This error is numerically quantified for porous rock by comparing the equivalent permeability of three‐dimensional fracture networks with the values computed on arbitrarily extracted planar trace maps. A method to compute the full permeability tensor of three‐dimensional discrete fracture and matrix models is described. The method is based on the element‐wise averaging of pressure and flux, obtained from a finite element solution to the Laplace problem, and is validated against analytical expressions for periodic anisotropic porous media. For isotropic networks of power law size‐distributed fractures with length‐correlated aperture, two‐dimensional cut planes are shown to underestimate the magnitude of permeability by up to 3 orders of magnitude near the percolation threshold, approaching an average factor of deviation of 3 with increasing fracture density. At low‐fracture densities, percolation may occur in three dimensions but not in any of the two‐dimensional cut planes. Anisotropy of the equivalent permeability tensor varies accordingly and is more pronounced in two‐dimensional extractions. These results confirm that two‐dimensional analysis cannot be directly used as an approximation of three‐dimensional equivalent permeability. However, an alternative expression of the excluded area relates trace map fracture density to an equivalent three‐dimensional fracture density, yielding comparable minimum and maximum permeability. This formulation can be used to approximate three‐dimensional flow properties in cases where only two‐dimensional analysis is available.

  • Journal article
    Amaechi B, Iglauer S, Pentland CH, Bijeljic B, Blunt MJet al., 2014,

    An Experimental Study of Three-Phase Trapping in Sand Packs

    , TRANSPORT IN POROUS MEDIA, Vol: 103, Pages: 421-436, ISSN: 0169-3913
  • Journal article
    Andrew M, Bijeljic B, Blunt MJ, 2014,

    Pore-scale contact angle measurements at reservoir conditions using X-ray microtomography

    , Advances in Water Resources, Vol: 68, Pages: 24-31, ISSN: 0309-1708

    Contact angle is a principal control of the flow of multiple fluid phases through porous media; however its measurement on other than flat surfaces remains a challenge. A new method is presented for the measurement of the contact angle between immiscible fluids at the pore scale at reservoir conditions (10 MPa and 50 °C) inside a quarry limestone through the use of X-ray microtomography. It is applied to a super-critical CO2–brine–carbonate system by resampling the micro-CT data onto planes orthogonal to the contact lines, allowing for vectors to be traced along the grain surface and the CO2–brine interface. A distribution of contact angles ranging from 35° to 55° is observed, indicating that the CO2–brine–carbonate system is weakly water-wet. This range of contact angles can be understood as the result of contact angle hysteresis and surface heterogeneity on a range of length scales. Surface heterogeneity is examined by comparison of micro-CT results with optical thin sections and SEM images.

  • Journal article
    Carriero A, Zimmermann EA, Paluszny A, Tang SY, Bale H, Busse B, Alliston T, Kazakia G, Ritchie RO, Shefelbine SJet al., 2014,

    How tough Is brittle bone? Investigating osteogenesis imperfecta in mouse bone

    , Journal of Bone and Mineral Research, Vol: 29, Pages: 1392-1401, ISSN: 0884-0431

    The multiscale hierarchical structure of bone is naturally optimized to resist fractures. In osteogenesis imperfecta, or brittle bone disease, genetic mutations affect the quality and/or quantity of collagen, dramatically increasing bone fracture risk. Here we reveal how the collagen defect results in bone fragility in a mouse model of osteogenesis imperfecta (oim), which has homotrimeric α1(I) collagen. At the molecular level, we attribute the loss in toughness to a decrease in the stabilizing enzymatic cross-links and an increase in nonenzymatic cross-links, which may break prematurely, inhibiting plasticity. At the tissue level, high vascular canal density reduces the stable crack growth, and extensive woven bone limits the crack-deflection toughening during crack growth. This demonstrates how modifications at the bone molecular level have ramifications at larger length scales affecting the overall mechanical integrity of the bone; thus, treatment strategies have to address multiscale properties in order to regain bone toughness. In this regard, findings from the heterozygous oim bone, where defective as well as normal collagen are present, suggest that increasing the quantity of healthy collagen in these bones helps to recover toughness at the multiple length scales.

  • Journal article
    Dale A, John CM, Mozley PS, Smalley PC, Muggeridge AHet al., 2014,

    Time-capsule concretions: unlocking burial diagenetic processes in the Mancos Shale using carbonate clumped isotopes

    , Earth and Planetary Science Letters, Vol: 394, Pages: 30-37, ISSN: 0012-821X
  • Journal article
    Solano JMS, Jackson MD, Sparks RSJ, Blundy Jet al., 2014,

    Evolution of major and trace element composition during melt migration through crystalline mush: Implications for chemical differentiation in the crust

    , American Journal of Science, Vol: 314, Pages: 895-939, ISSN: 0002-9599

    We present the first quantitative model of heat, mass and both majorand trace element transport in a mush undergoing compaction that accounts forcomponent transport and chemical reaction during melt migration and which isapplicable to crustal systems. The model describes the phase behavior of binarysystems (both eutectic and solid solution), with melt and solid compositions determinedfrom phase diagrams using the local temperature and bulk composition. Traceelement concentration is also determined. The results demonstrate that componenttransport and chemical reaction generate compositional variation in both major andtrace elements that is not captured by existing geochemical models. In particular, wefind that, even for the simplest case of a homogenous, insulated column that isinstantaneously melted then allowed to compact, component transport and reactionleads to spatial variations in major element composition that, in this case, producesmelt that is more enriched in incompatible elements than predicted by batch melting.In deep crustal hot zones (DCHZ), created by the repeated intrusion of hot, mantlederivedmagmas, buoyant melt migrating upwards accumulates in high porosity layers,but has a composition corresponding to only a small fraction of batch melting, becauseit has locally equilibrated with mush at low temperature; moreover, melt migration andchemical reaction in a layered protolith may lead to the rapid formation of highporosity melt layers at the interface between different rock compositions. In both ofthese cases, the melt in the high porosity layer(s) is less enriched in incompatible traceelements than predicted if it is assumed that melt with the same major elementcomposition was produced by batch melting. This distinctive decoupling of major andtrace element fractionation may be characteristic of magmas that originate in DCHZ.Application of the model to a number of crustal systems, including the Ivrea-Verbanozone, the Rum layered intrusion, and the Hol

  • Journal article
    Leal AMM, Blunt MJ, LaForce TC, 2014,

    Efficient chemical equilibrium calculations for geochemical speciation and reactive transport modelling

    , GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 131, Pages: 301-322, ISSN: 0016-7037
  • Journal article
    Deveugle PEK, Jackson MD, Hampson GJ, Stewart J, Clough MD, Ehighebolo T, Farrell ME, Calvert CS, Miller JKet al., 2014,

    A comparative study of reservoir modeling techniques and their impact on predicted performance of fluvial-dominated deltaic reservoirs

    , AAPG BULLETIN, Vol: 98, Pages: 729-763, ISSN: 0149-1423
  • Journal article
    Alkhatib A, King P, 2014,

    An approximate dynamic programming approach to decision making in the presence of uncertainty for surfactant-polymer flooding

    , Computational Geosciences: modeling, simulation and data analysis, Vol: 18, Pages: 243-263, ISSN: 1420-0597

    The least squares Monte Carlo method is a decision evaluation method that can capture the effect of uncertainty and the value of flexibility of a process. The method is a stochastic approximate dynamic programming approach to decision making. It is based on a forward simulation coupled with a recursive algorithm which produces the near-optimal policy. It relies on the Monte Carlo simulation to produce convergent results. This incurs a significant computational requirement when using this method to evaluate decisions for reservoir engineering problems because this requires running many reservoir simulations. The objective of this study was to enhance the performance of the least squares Monte Carlo method by improving the sampling method used to generate the technical uncertainties used in obtaining the production profiles. The probabilistic collocation method has been proven to be a robust and efficient uncertainty quantification method. By using the sampling methods of the probabilistic collocation method to approximate the sampling of the technical uncertainties, it is possible to significantly reduce the computational requirement of running the decision evaluation method. Thus, we introduce the least squares probabilistic collocation method. The decision evaluation considered a number of technical and economic uncertainties. Three reservoir case studies were used: a simple homogeneous model, the PUNQ-S3 model, and a modified portion of the SPE10 model. The results show that using the sampling techniques of the probabilistic collocation method produced relatively accurate responses compared with the original method. Different possible enhancements were discussed in order to practically adapt the least squares probabilistic collocation method to more realistic and complex reservoir models. Furthermore, it is desired to perform the method to evaluate high-dimensional decision scenarios for different chemical enhanced oil recovery processes using real reservoir data.

  • Journal article
    Matsushima T, Blumenfeld R, 2014,

    Universal Structural Characteristics of Planar Granular Packs

    , PHYSICAL REVIEW LETTERS, Vol: 112, ISSN: 0031-9007
  • Journal article
    Andrew M, Bijeljic B, Blunt MJ, 2014,

    Pore-scale imaging of trapped supercritical carbon dioxide in sandstones and carbonates

    , International Journal of Greenhouse Gas Control, Vol: 22, Pages: 1-14, ISSN: 1750-5836

    Geological carbon dioxide storage must be designed such that the CO2 cannot escape from the rock formation into which it is injected, and often simple stratigraphic trapping is insufficient. CO2 can be trapped in the pore space as droplets surrounded by water through capillary trapping. X-ray microtomography was used to image, at a resolution of 6.6 μm, the pore-scale arrangement of these droplets in three carbonates and two sandstones. The pressures and temperatures in the pore space were representative of typical storage formations, while chemical equilibrium was maintained between the CO2, brine and rock phases to replicate conditions far away from the injection site. In each sample substantial amounts of CO2 were trapped, with the efficiency of trapping being insensitive to pore-morphology and chemistry. Apart from in one extremely well connected sample, the size distribution of residual ganglia larger than 105 voxel3 obey power law distributions with exponents broadly consistent with percolation theory over two orders of magnitude. This work shows that residual trapping can be used to locally immobilise CO2 in a wide range of rock types.

  • Journal article
    Amin SM, Weiss DJ, Blunt MJ, 2014,

    Reactive transport modelling of geologic CO2 sequestration in saline aquifers: The influence of pure CO2 and of mixtures of CO2 with CH4 on the sealing capacity of cap rock at 37 degrees C and 100 bar

    , CHEMICAL GEOLOGY, Vol: 367, Pages: 39-50, ISSN: 0009-2541
  • Journal article
    Sadeghnejad S, Masihi M, Pishvaie M, Shojaei A, King PRet al., 2014,

    Estimating the Connected Volume of Hydrocarbon During Early Reservoir Life by Percolation Theory

  • Journal article
    Alkhatib A, King P, 2014,

    Robust quantification of parametric uncertainty for surfactant-polymer flooding

    , COMPUTATIONAL GEOSCIENCES, Vol: 18, Pages: 77-101, ISSN: 1420-0597
  • Journal article
    Guadagnini A, Blunt MJ, Riva M, Bijeljic Bet al., 2014,

    Statistical Scaling of Geometric Characteristics in Millimeter Scale Natural Porous Media

    , TRANSPORT IN POROUS MEDIA, Vol: 101, Pages: 465-475, ISSN: 0169-3913
  • Journal article
    Fitch PJR, Jackson MD, Hampson GJ, John CMet al., 2014,

    Interaction of stratigraphic and sedimentological heterogeneities with flow in carbonate ramp reservoirs: impact of fluid properties and production strategy

    , Petroleum Geoscience, Vol: 20, Pages: 7-26, ISSN: 1354-0793

    It is well known that heterogeneities in carbonate reservoirs impact fluid flow during production. However, few studies have examined the impact of the same heterogeneities on flow behaviour with different fluid properties and production scenarios. We use integrated flow simulation and experimental design techniques to investigate the relative, first-order impact of stratigraphic and sedimentological heterogeneities on simulated recovery in carbonate ramp reservoirs. Two production strategies are compared, which promote dominance of either horizontal or vertical flow.We find that the modelled geology is more important than the simulated fluid properties and production scenarios over the ranges tested. Of the heterogeneities modelled here, rock properties and stratigraphic heterogeneities that control reservoir architecture and the spatial distribution of environment of deposition (EOD) belts are important controls on recovery regardless of the production strategy. The presence of cemented hardground surfaces becomes the key control on oil recovery in displacements dominated by vertical flow. Permeability anisotropy is of low importance for all production strategies. The impacts of stratigraphic heterogeneities on recovery factor and water breakthrough are more strongly influenced by fluid properties and well spacing in displacements dominated by vertical flow. These results help to streamline the reservoir modelling process, by identifying key heterogeneities, and to optimize production strategies.

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