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Progress in Natural Science:Materials International 2017年第1期27卷 93-98页

作者： S.Suwarno M.Williams J.K.Solberg V.A.Yartys Department of Mechanical Engineering Institut Teknologi Sepuluh Nopember Department of Materials Science and Engineering NTNU Institute for Energy Technology University of the Western Cape

The hydrogenation properties of Ti-V hydrides coated with nanoparticles have been studied in gaseous mixtures of argon and hydrogen with and without additions of 1% CO. Nanoparticles of Pd, Ni, and co-deposited Pd/Pt with particle sizes of;0–60 nm were formed by electroless deposition on the hydride surfaces. The alloy resistance to CO could be significantly improved by particle deposition. Large amounts of hydrogen were absorbed in a CO-containing gas when Ni and Pd/Pt deposition had been applied, while pure Pd deposition had no positive effect. Ni was found to have a stronger effect than those of Pd/Pt and Pd, possibly because of the size effect of Ni nanoparticles.

关键词： Metal hydride Titanium Vanadium Nanoparticle Palladium Nickel Platinum Carbon monoxide

Particle Collisions in a Lumped Particle Model

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Communications in Computational Physics 2011年第9期10卷 823-843页

作者： Omar al-Khayat Are Magnus Bruaset Hans Petter Langtangen Computational Geosciences CBCSimula Research LaboratoryP.O.Box 134NO-1325 LysakerNorway Department of Informatics University of OsloP.O.Box 1080BlindernNO-0316 OsloNorway Center for Biomedical Computing Simula Research LaboratoryP.O.Box 134NO-1325 LysakerNorway

This paper presents an extension of the lumped particle model in[1]to include the effects of particle *** lumped particle model is a flexible framework for the modeling of particle laden flows,that takes into account fundamental features,including advection,diffusion and dispersion of the *** this paper,we transform a binary collision model and concepts from kinetic theory into a collision procedure for the lumped particle *** apply this new collision procedure to investigate numerically the role of particle collisions in the hindered settling *** hindered settling effect is characterized by an increase in the effective drag coefficient CD that influences each particle in the *** coefficient is given by CD=(1−φ)−nC∗D,whereφis the volume fraction of particles,C∗D is the drag coefficient for a single particle,and n≃4.67 for creeping *** obtain an approximation for CD/C∗D by calculating the effective work done by collisions,and comparing that to the work done by the drag *** our numerical experiments,we observe a minimal value of n=***,by allowing high energy dissipation,an approximation for the classical value for creeping flow,n=4.7,is *** also obtain high values for n,up to n=6.5,which is consistent with recent physical experiments on the sedimentation of sand grains.

关键词： Lumped particle model particle collision hindered settling

Computational Aspects of Multiscale Simulationwith the Lumped Particle Framework

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Communications in Computational Physics 2012年第9期12卷 1257-1274页

作者： Omar al-Khayat Hans Petter Langtangen Computational Geosciences CBCSimula Research LaboratoryP.O.Box 134NO-1325 LysakerNorway Department of Informatics University of OsloP.O.Box 1080BlindernNO-0316 OsloNorway Center for Biomedical Computing Simula Research LaboratoryP.O.Box 134NO-1325 LysakerNorway

First introduced in[2],the lumped particle framework is a flexible and numerically efficient framework for the modelling of particle transport in fluid *** this paper,the framework is expanded to simulate multicomponent particle-laden fluid *** is accomplished by introducing simulation protocols tomodel particles over a wide range of length and time ***,we present a time ordering scheme and an approximate approach for accelerating the computation of evolution of different particle constituents with large differences in physical *** apply the extended framework on the temporal evolution of three particle constituents in sandladen flow,and horizontal release of spherical ***,we evaluate the numerical error of the lumped particle *** this context,we discuss the Velocity-Verlet numerical scheme,and show how to apply this to solving Newton’s equations within the *** show that the increased accuracy of the Velocity-Verlet scheme is not lost when applied to the lumped particle framework.

关键词： Multiscale modelling lumped particle model Velocity-Verlet scheme

Hybrid connectionist model determines CO_2–oil swelling factor

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Petroleum Science 2018年第3期15卷 591-604页

作者： Mohammad Ali Ahmadi Sohrab Zendehboudi Lesley A. James Faculty of Engineering and Applied Science Memorial University of Newfoundland St. John's NL A1C 5S7 Canada

In-depth understanding of interactions between crude oil and CO2 provides insight into the CO2-based enhanced oil recovery（EOR） process design and simulation. When CO2 contacts crude oil, the dissolution process takes place. This phenomenon results in the oil swelling, which depends on the temperature, pressure, and composition of the oil. The residual oil saturation in a CO2-based EOR process is inversely proportional to the oil swelling factor. Hence, it is important to estimate this influential parameter with high precision. The current study suggests the predictive model based on the least-squares support vector machine（LS-SVM） to calculate the CO2–oil swelling factor. A genetic algorithm is used to optimize hyperparameters（у and б^2） of the LS-SVM model. This model showed a high coefficient of determination（R^2= 0.9953） and a low value for the mean-squared error（MSE = 0.0003） based on the available experimental data while estimating the CO2–oil swelling factor. It was found that LS-SVM is a straightforward and accurate method to determine the CO2–oil swelling factor with negligible uncertainty. This method can be incorporated in commercial reservoir simulators to include the effect of the CO2–oil swelling factor when adequate experimental data are not available.

关键词： C02 injection CO2 swelling Genetic algorithm Predictive model Least-squares support vector machine

Reservoir quality of fluvial sandstone reservoirs in salt-walled mini- basins： an example from the Seagull field, Central Graben, North Sea, UK

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Petroleum Science 2018年第1期15卷 1-27页

作者： Stephan Stricker Stuart J.Jones Neil Meadows Leon Bowen Department of Earth Sciences Durham University South Road Durham DH1 3LE UK RedRock Associates International Limited 38 Queens DrivePrenton Wirral CH43 0RP UK Department of Physics Durham University South RoadDurham DH1 3LE UK

The Triassic fluvial sandstones of the Skagerrak Formation were deposited in a series of salt-walled mini-basins and act as important hydrocarbon reservoirs for several high-pressure, high-temperature（HPHT） fields in the Central Graben, North Sea. The HPHT reservoirs exhibit excellent reservoir quality considering their depth of burial and hence have been of high interest for hydrocarbon exploration. This research uses a multidisciplinary approach to assess the Skagerrak Formation fluvial reservoir quality from the Seagull field incorporating core analysis, petrography, electron microscopy, XRD analysis, fluid inclusion appraisal and burial history modelling. Halokinesis and salt withdrawal at the margin of the saltwalled mini-basin induced early disaggregation bands and fractures at shallow burial and led to increased influx of meteoric water and clay mineral infiltration from overlying sedimentation. The density of disaggregation bands correlates with the occurrence and magnitude of pore-filling authigenic clay minerals, concentrated along the margin of the saltwalled mini-basin. The fluvial channel sandstones of the Skagerrak Formation are subject to strong intra-basinal spatial reservoir quality variations despite diagenesis and low vertical effective stress having played a favourable role in arresting porosity loss.

关键词： Reservoir quality Halokinesis - Diagenesis Clay minerals Porosity Disaggregation bands Salt-walled mini-basin

A nearly analytic exponential time difference method for solving 2D seismic wave equations

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Earthquake Science 2014年第1期27卷 57-77页

作者： Xiao Zhang Dinghui Yang Guojie Song Department of Mathematical Sciences Tsinghua University

In this paper, we propose a nearly analytic exponential time difference （NETD） method for solving the 2D acoustic and elastic wave equations. In this method, we use the nearly analytic discrete operator to approximate the high-order spatial differential operators and transform the seismic wave equations into semi-discrete ordinary differential equations （ODEs）. Then, the converted ODE system is solved by the exponential time difference （ETD） method. We investigate the properties of NETD in detail, including the stability condition for 1-D and 2-D cases, the theoretical and relative errors, the numerical dispersion relation for the 2-D acoustic case, and the computational efficiency. In order to further validate the method, we apply it to simulating acoustic/elastic wave propagation in mul- tilayer models which have strong contrasts and complex heterogeneous media, e.g., the SEG model and the Mar- mousi model. From our theoretical analyses and numerical results, the NETD can suppress numerical dispersion effectively by using the displacement and gradient to approximate the high-order spatial derivatives. In addition, because NETD is based on the structure of the Lie group method which preserves the quantitative properties of differential equations, it can achieve more accurate results than the classical methods.

关键词： ETD Lie group method Numerical approximations and analysis Computational seismology - Numerical dispersion Nearly analytic discrete operator

Amine reclaiming technologies in post-combustion carbon dioxide capture

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Journal of Environmental Sciences 2015年第1期27卷 276-289页

作者： Tielin Wang Jon Hovland Klaus J.Jens Telemark University College Tel-Tek Porsgrunn 3918 Norway

Amine scrubbing is the most developed technology for carbon dioxide（CO2） *** of amine solvents due to the presence of high levels of oxygen and other impurities in flue gas causes increasing costs and deterioration in long term performance,and therefore purification of the solvents is needed to overcome these problems. This review presents the reclaiming of amine solvents used for post combustion CO2capture（PCC）. Thermal reclaiming, ion exchange, and electrodialysis, although principally developed for sour gas sweetening, have also been tested for CO2 capture from flue *** three technologies all have their strengths and weaknesses, and further development is needed to reduce energy usage and costs. An expected future trend for amine reclamation is to focus on process integration of the current reclaiming technologies into the PCC process in order to drive down costs.

关键词： Carbon dioxide capture Amine reclaiming Distillation Ion exchange Electrodialysis

Reservoir stress path and induced seismic anisotropy： results from linking coupled fluid-flow/geomechanical simulation with seismic modelling

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Petroleum Science 2016年第4期13卷 669-684页

作者： D.A.Angus Q.J.Fisher J.M.Segura J.P.Verdon J.-M.Kendall M.Dutko A.J.L.Crook School of Earth and Environment University of LeedsLeeds UK Formerly School of Earth and Environment University of Leeds Leeds UK Department of Earth Sciences University of Bristol BristolUK Rockfield Software Ltd. Swansea UK Three Cliffs Geomechanics Swansea UK Repsol Madrid Spain ESG Solutions Kingston Canada

We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by non-hydrostatic stress changes. We generate seismic models from coupled simulations to examine the relationship between reservoir geometry, stress path and seismic anisotropy. The results indicate that geometry influences the evolution of stress,which leads to stress-induced seismic anisotropy. Although stress anisotropy is high for the small reservoir, the effect of stress arching and the ability of the side-burden to support the excess load limit the overall change in effective stress and hence seismic anisotropy. For the extensive reservoir, stress anisotropy and induced seismic anisotropy are high. The extensive and elongate reservoirs experience significant compaction, where the inefficiency of the developed stress arching in the side-burden cannot support the excess *** elongate reservoir displays significant stress asymmetry,with seismic anisotropy developing predominantly along the long-edge of the reservoir. We show that the link betweenstress path parameters and seismic anisotropy is complex,where the anisotropic symmetry is controlled not only by model geometry but also the nonlinear rock physics model used. Nevertheless, a workflow has been developed to model seismic anisotropy induced by non-hydrostatic stress changes, allowing field observations of anisotropy to be linked with geomechanical models.

关键词： Coupled fluid-flow/geomechanics Reservoir characterization Seismic anisotropy Stress path

Target-Oriented Inversion of Time-Lapse Seismic Waveform Data

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Communications in Computational Physics 2020年第6期28卷 249-275页

作者： Xingguo Huang Morten Jakobsen Kjersti Solberg Eikrem Geir Nævdal Department of Earth Science University of BergenP.O.Box 78035020 BergenNorway NORCE Norwegian Research Centre Postboks 225838 BergenNorway

Full waveform inversion of time-lapse seismic data can be used as a means of estimating the reservoir changes due to the *** the repeated computa-tions for the monitor surveys lead to a large computational cost,time-lapse full wave-form inversion is still considered to be a challenging *** address this problem,we present an efficient target-oriented inversion scheme for time-lapse seismic data using an integral equation formulation with Gaussian beam based Green’s function *** proposed time-lapse approach allows one to perform a local inversion within a small region of interest(e.g.a reservoir under production)for the monitor *** have verified that the T-matrix approach is indeed naturally target-oriented,which was mentioned by Jakobsen and Ursin[24]and allows one to reduce the compu-tational cost of time-lapse inversion by focusing the inversion on the target-area *** method is based on a new version of the distorted Born iterative T-matrix inverse scattering *** Gaussian beam and T-matrix are used in this approach to perform the wavefield computation for the time-lapse inversion in the baseline model from the survey surface to the target *** have provided target-oriented inversion results of the synthetic time-lapse waveform data,which shows that the proposed scheme reduces the computational cost significantly.

关键词： Waveform inversion time-lapse seismic seismic inverse scattering target-oriented inversion Gaussian beam based Green’s function

Modeling nanoscale ice adhesion

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Acta Mechanica Solida Sinica 2017年第3期30卷 224-226页

作者： Senbo Xiao Jianying He Zhiliang Zhang NTNU Nanomechanical Lab Department of Structural Engineering Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway

Anti-icing is crucial for numerous instruments and devices in low temperature circum- stance. One of the approaches in anti-icing is to reduce ice adhesion strength, seeking spontaneous de-icing processes by natural forces of gravity or by winds. In order to enable tai- lored surface icephobicity design, research requires a good theoretical understanding of the atomistic interacting mechanisms between water/ice molecules and their adhering substrates. Herein, this work focuses on using atomistic modeling and molecular dynamics simulation to build a nanosized ice-cube adhering onto silicon surface, with different contact modes of solid-solid and solid-liquid-solid patterns. This study provides atomistic models for probing nanoscale ice adhesion mechanics and theoretical platforms for explaining experimental results.

关键词： Anti-icing Atomistic modeling Molecular dynamics Adhesion Interface mechanics