383 results found
Akai T, Bijeljic B, Blunt MJ, 2018, Wetting boundary condition for the color-gradient lattice Boltzmann method: Validation with analytical and experimental data, ADVANCES IN WATER RESOURCES, Vol: 116, Pages: 56-66, ISSN: 0309-1708
Al-Khulaifi Y, Lin Q, Blunt MJ, et al., 2018, Reservoir-condition pore-scale imaging of dolomite reaction with supercritical CO2 acidified brine: Effect of pore-structure on reaction rate using velocity distribution analysis, INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 68, Pages: 99-111, ISSN: 1750-5836
Alyafei N, Blunt MJ, 2018, Estimation of relative permeability and capillary pressure from mass imbibition experiments, ADVANCES IN WATER RESOURCES, Vol: 115, Pages: 88-94, ISSN: 0309-1708
Bultreys T, Lin Q, Gao Y, et al., 2018, Validation of model predictions of pore-scale fluid distributions during two-phase flow, PHYSICAL REVIEW E, Vol: 97, ISSN: 2470-0045
Lin Q, Andrew M, Thompson W, et al., 2018, Optimization of image quality and acquisition time for lab-based X-ray microtomography using an iterative reconstruction algorithm, ADVANCES IN WATER RESOURCES, Vol: 115, Pages: 112-124, ISSN: 0309-1708
Menke HP, Reynolds CA, Andrew MG, et al., 2018, 4D multi-scale imaging of reactive flow in carbonates: Assessing the impact of heterogeneity on dissolution regimes using streamlines at multiple length scales, CHEMICAL GEOLOGY, Vol: 481, Pages: 27-37, ISSN: 0009-2541
Mosser L, Dubrule O, Blunt MJ, 2018, Stochastic Reconstruction of an Oolitic Limestone by Generative Adversarial Networks, Transport in Porous Media, Pages: 1-23, ISSN: 0169-3913
© 2018 The Author(s) Stochastic image reconstruction is a key part of modern digital rock physics and material analysis that aims to create representative samples of microstructures for upsampling, upscaling and uncertainty quantification. We present new results of a method of three-dimensional stochastic image reconstruction based on generative adversarial neural networks (GANs). GANs are a family of unsupervised learning methods that require no a priori inference of the probability distribution associated with the training data. Thanks to the use of two convolutional neural networks, the discriminator and the generator, in the training phase, and only the generator in the simulation phase, GANs allow the sampling of large and realistic volumetric images. We apply a GAN-based workflow of training and image generation to an oolitic Ketton limestone micro-CT unsegmented gray-level dataset. Minkowski functionals calculated as a function of the segmentation threshold are compared between simulated and acquired images. Flow simulations are run on the segmented images, and effective permeability and velocity distributions of simulated flow are also compared. Results show that GANs allow a fast and accurate reconstruction of the evaluated image dataset. We discuss the performance of GANs in relation to other simulation techniques and stress the benefits resulting from the use of convolutional neural networks . We address a number of challenges involved in GANs, in particular the representation of the probability distribution associated with the training data.
Nooruddin HA, Blunt MJ, 2018, Large-scale Invasion Percolation with Trapping for Upscaling Capillary-Controlled Darcy-scale Flow, TRANSPORT IN POROUS MEDIA, Vol: 121, Pages: 479-506, ISSN: 0169-3913
Raeini AQ, Bijeljic B, Blunt MJ, 2018, Generalized network modeling of capillary-dominated two-phase flow, PHYSICAL REVIEW E, Vol: 97, ISSN: 2470-0045
Reynolds CA, Blunt MJ, Krevor S, 2018, Multiphase Flow Characteristics of Heterogeneous Rocks From CO2 Storage Reservoirs in the United Kingdom, WATER RESOURCES RESEARCH, Vol: 54, Pages: 729-745, ISSN: 0043-1397
Shams M, Raeini AQ, Blunt MJ, et al., 2018, A numerical model of two-phase flow at the micro-scale using the volume-of-fluid method, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 357, Pages: 159-182, ISSN: 0021-9991
Shams M, Raeini AQ, Blunt MJ, et al., 2018, A study to investigate viscous coupling effects on the hydraulic conductance of fluid layers in two-phase flow at the pore level, JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 522, Pages: 299-310, ISSN: 0021-9797
Al-Khulaifi Y, Lin Q, Blunt MJ, et al., 2017, Reaction Rates in Chemically Heterogeneous Rock: Coupled Impact of Structure and Flow Properties Studied by X-ray Microtomography, ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 51, Pages: 4108-4116, ISSN: 0013-936X
AlRatrout A, Raeini AQ, Bijeljic B, et al., 2017, Automatic measurement of contact angle in pore-space images, ADVANCES IN WATER RESOURCES, Vol: 109, Pages: 158-169, ISSN: 0309-1708
Alhammadi AM, AlRatrout A, Bijeljic B, et al., 2017, In situ wettability measurement in a carbonate reservoir rock at high temperature and pressure
© 2017, Society of Petroleum Engineers. More than a trillion barrels of oil may be extracted from carbonate reservoirs in the Middle East. Oil recovery is known to be controlled by wettability (distribution of contact angles) that determines the pore-scale fluid configuration. However, these contact angles have not hitherto been measured in situ at reservoir conditions for reservoir rock that is saturated with formation brine and crude oil. We use high resolution X-ray imaging of a sample from a producing oil field to demonstrate that contact angles over a wide range are seen both above and below 90°. More than a million points of contact angle were measured after three pore volumes of formation brine flooding. The injected brine invades the center of the pores as a non-wetting phase leaving oil trapped in small pores and corners in connected layers. Pores that were filled with initial formation brine remained water-wet. On the other hand, surfaces that were in direct contact with crude oil during aging were altered to oil-wet. However, water-wet surfaces were also measured in pores that were filled with crude oil which suggests that water layers in small pores, crevices, and within rock surface roughness, which might be connected to brine in micro-porosity, could prevent the contact between surface active polar compounds in the crude oil and the rock surfaces preventing strong wettability change. The reservoir rock became mixed-wet with a mean contact angle of 106° ± 20° obtained from 1.36 million in situ contact angle values measured using an automated algorithm (AlRatrout et al., 2017) applied on segmented three-dimensional X-ray image. The three-dimensional images were acquired using a high resolution X-ray micro-tomography scanner. The wetting condition resulted in a large volume of oil (50.6%) being trapped with a distinctive morphology as rough sheet-like layers.
Alhammadi AM, AlRatrout A, Singh K, et al., 2017, In situ characterization of mixed-wettability in a reservoir rock at subsurface conditions, SCIENTIFIC REPORTS, Vol: 7, ISSN: 2045-2322
Bartels W-B, Rucker M, Berg S, et al., 2017, Fast X-Ray Micro-CT Study of the Impact of Brine Salinity on the Pore-Scale Fluid Distribution During Waterflooding, SCA International Symposium, Publisher: SOC PETROPHYSICISTS & WELL LOG ANALYSTS-SPWLA, Pages: 36-47, ISSN: 1529-9074
Foley AY, Nooruddin HA, Blunt MJ, 2017, The impact of capillary backpressure on spontaneous counter-current imbibition in porous media, ADVANCES IN WATER RESOURCES, Vol: 107, Pages: 405-420, ISSN: 0309-1708
Gao Y, Lin Q, Bijeljic B, et al., 2017, X-ray Microtomography of Intermittency in Multiphase Flow at Steady State Using a Differential Imaging Method, WATER RESOURCES RESEARCH, Vol: 53, Pages: 10274-10292, ISSN: 0043-1397
Lin Q, Bijeljic B, Rieke H, et al., 2017, Differential imaging of porous plate capillary drainage in laminated sandstone rock using X-ray micro-tomography
The experimental determination of representative capillary pressure curves as a function of saturation is of utmost importance for the determination of the initial reservoir fluid distribution and subsequent flow properties under production. We design an experimental procedure to image porous plate capillary drainage using X-ray micro-tomography based on differential imaging for a laminated sandstone micro core (4.86 mm in diameter). The pore structure, including the sub-resolution micro pores, was characterised and quantified using both the initial dry scan and the scan fully saturated with Potassium Iodide (KI) doped brine (30 wt%). During the porous plate capillary drainage, nitrogen (N2) was injected at a constant pressure and the capillary pressure was controlled by the pressure drop through the core sample. A full range of capillary pressure curve against saturation from 0 to 1.17 MPa is provided from the image analysis and is compared with the Special Core Analysis (SCAL) for the original core (35 mm in diameter). We are also able to discern that brine remained predominantly within the sub-resolution micro-pores, such as regions of fine lamination. Moreover, brine covering the rock grain surface and in the corners of the macro-pores can also be visualised.
Lin Q, Bijeljic B, Rieke H, et al., 2017, Visualization and quantification of capillary drainage in the pore space of laminated sandstone by a porous plate method using differential imaging X-ray microtomography, WATER RESOURCES RESEARCH, Vol: 53, Pages: 7457-7468, ISSN: 0043-1397
Menke HP, Andrew MG, Vila-Comamala J, et al., 2017, Dynamic Pore-scale Reservoir-condition Imaging of Reaction in Carbonates Using Synchrotron Fast Tomography, JOVE-JOURNAL OF VISUALIZED EXPERIMENTS, ISSN: 1940-087X
Menke HP, Bijeljic B, Blunt MJ, 2017, Dynamic reservoir-condition microtomography of reactive transport in complex carbonates: Effect of initial pore structure and initial brine pH, GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 204, Pages: 267-285, ISSN: 0016-7037
Mosser L, Dubrule O, Blunt MJ, 2017, Reconstruction of three-dimensional porous media using generative adversarial neural networks, PHYSICAL REVIEW E, Vol: 96, ISSN: 2470-0045
Muljadi BP, Bijeljic B, Blunt MJ, et al., 2017, Modelling and upscaling of transport in carbonates during dissolution: Validation and calibration with NMR experiments., J Contam Hydrol
We present an experimental and numerical study of transport in carbonates during dissolution and its upscaling from the pore (∼μm) to core (∼cm) scale. For the experimental part, we use nuclear magnetic resonance (NMR) to probe molecular displacements (propagators) of an aqueous hydrochloric acid (HCl) solution through a Ketton limestone core. A series of propagator profiles are obtained at a large number of spatial points along the core at multiple time-steps during dissolution. For the numerical part, first, the transport model-a particle-tracking method based on Continuous Time Random Walks (CTRW) by Rhodes et al. (2008)-is validated at the pore scale by matching to the NMR-measured propagators in a beadpack, Bentheimer sandstone, and Portland carbonate (Scheven et al., 2005). It was found that the emerging distribution of particle transit times in these samples can be approximated satisfactorily using the power law function ψ(t) ∼ t-1-β, where 0 <β < 2. Next, the evolution of the propagators during reaction is modelled: at the pore scale, the experimental data is used to calibrate the CTRW parameters; then the shape of the propagators is predicted at later observation times. Finally, a numerical upscaling technique is employed to obtain CTRW parameters for the core. From the NMR-measured propagators, an increasing frequency of displacements in stagnant regions was apparent as the reaction progressed. The present model predicts that non-Fickian behaviour exhibited at the pore scale persists on the centimetre scale.
Raeini AQ, Bijeljic B, Blunt MJ, 2017, Generalized network modeling: Network extraction as a coarse-scale discretization of the void space of porous media, PHYSICAL REVIEW E, Vol: 96, ISSN: 2470-0045
Reynolds CA, Menke H, Andrew M, et al., 2017, Dynamic fluid connectivity during steady-state multiphase flow in a sandstone, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 114, Pages: 8187-8192, ISSN: 0027-8424
Saif T, Lin Q, Bijeljic B, et al., 2017, Microstructural imaging and characterization of oil shale before and after pyrolysis, FUEL, Vol: 197, Pages: 562-574, ISSN: 0016-2361
Saif T, Lin Q, Butcher AR, et al., 2017, Multi-scale multi-dimensional microstructure imaging of oil shale pyrolysis using X-ray micro-tomography, automated ultra-high resolution SEM, MAPS Mineralogy and FIB-SEM, APPLIED ENERGY, Vol: 202, Pages: 628-647, ISSN: 0306-2619
Scanziani A, Singh K, Blunt MJ, et al., 2017, Automatic method for estimation of in situ effective contact angle from X-ray micro tomography images of two-phase flow in porous media, JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 496, Pages: 51-59, ISSN: 0021-9797
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