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  1. Article ; Online: Heterogeneous multiphase flow properties of volcanic rocks and implications for noble gas transport from underground nuclear explosions

    Jason E. Heath / Kristopher L. Kuhlman / Scott T. Broome / Jennifer E. Wilson / Bwalya Malama

    Vadose Zone Journal, Vol 20, Iss 3, Pp n/a-n/a (2021)

    2021  

    Abstract: Abstract Of interest to the Underground Nuclear Explosion Signatures Experiment are patterns and timing of explosion‐generated noble gases that reach the land surface. The impact of potentially simultaneous flow of water and gas on noble gas transport in ...

    Abstract Abstract Of interest to the Underground Nuclear Explosion Signatures Experiment are patterns and timing of explosion‐generated noble gases that reach the land surface. The impact of potentially simultaneous flow of water and gas on noble gas transport in heterogeneous fractured rock is a current scientific knowledge gap. This article presents field and laboratory data to constrain and justify a triple continua conceptual model with multimodal multiphase fluid flow constitutive equations that represents host rock matrix, natural fractures, and induced fractures from past underground nuclear explosions (UNEs) at Aqueduct and Pahute Mesas, Nevada National Security Site, Nevada, USA. Capillary pressure from mercury intrusion and direct air–water measurements on volcanic tuff core samples exhibit extreme spatial heterogeneity (i.e., variation over multiple orders of magnitude). Petrographic observations indicate that heterogeneity derives from multimodal pore structures in ash‐flow tuff components and post‐depositional alteration processes. Comparisons of pre‐ and post‐UNE samples reveal different pore size distributions that are due in part to microfractures. Capillary pressure relationships require a multimodal van Genuchten (VG) constitutive model to best fit the data. Relative permeability estimations based on unimodal VG fits to capillary pressure can be different from those based on bimodal VG fits, implying the choice of unimodal vs. bimodal fits may greatly affect flow and transport predictions of noble gas signatures. The range in measured capillary pressure and predicted relative permeability curves for a given lithology and between lithologies highlights the need for future modeling to consider spatially distributed properties.
    Keywords Environmental sciences ; GE1-350 ; Geology ; QE1-996.5
    Subject code 550
    Language English
    Publishing date 2021-05-01T00:00:00Z
    Publisher Wiley
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Parameter estimation from spontaneous imbibition into volcanic tuff

    Kristopher L. Kuhlman / Melissa M. Mills / Jason E. Heath / Matthew J. Paul / Jennifer E. Wilson / John Eric Bower

    Vadose Zone Journal, Vol 21, Iss 2, Pp n/a-n/a (2022)

    2022  

    Abstract: Abstract Two‐phase fluid flow properties underlie quantitative prediction of water and gas movement, but constraining these properties typically requires multiple time‐consuming laboratory methods. The estimation of two‐phase flow properties (van ... ...

    Abstract Abstract Two‐phase fluid flow properties underlie quantitative prediction of water and gas movement, but constraining these properties typically requires multiple time‐consuming laboratory methods. The estimation of two‐phase flow properties (van Genuchten parameters, porosity, and intrinsic permeability) is illustrated in cores of vitric nonwelded volcanic tuff using Bayesian parameter estimation that fits numerical models to observations from spontaneous imbibition experiments. The uniqueness and correlation of the estimated parameters is explored using different modeling assumptions and subsets of the observed data. The resulting estimation process is sensitive to both moisture retention and relative permeability functions, thereby offering a comprehensive method for constraining both functions. The data collected during this relatively simple laboratory experiment, used in conjunction with a numerical model and a global optimizer, result in a viable approach for augmenting more traditional capillary pressure data obtained from hanging water column, membrane plate extractor, or mercury intrusion methods. This method may be useful when imbibition rather than drainage parameters are sought, when larger samples (e.g., including heterogeneity or fractures) need to be tested that cannot be accommodated in more traditional methods, or when in educational laboratory settings.
    Keywords Environmental sciences ; GE1-350 ; Geology ; QE1-996.5
    Subject code 310
    Language English
    Publishing date 2022-03-01T00:00:00Z
    Publisher Wiley
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    Inter-library loan at ZB MED

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  3. Article: Oedometric Small-Angle Neutron Scattering: In Situ Observation of Nanopore Structure During Bentonite Consolidation and Swelling in Dry and Hydrous CO2 Environments

    Dewers, Thomas A / Charles R. Bryan / Jason E. Heath / Joseph T. Mang / Mark Taylor / Mei Ding / Rex P. Hjelm

    Environmental science & technology. 2018 Feb. 19, v. 52, no. 6

    2018  

    Abstract: Results of oedometric consolidation experiments linked with small-angle neutron scattering (SANS) measurements are presented, using SWy-2 Wyoming bentonite clay in dry and water-bearing N2 and CO2 atmospheres. Oedometric SANS involves deforming a porous ... ...

    Abstract Results of oedometric consolidation experiments linked with small-angle neutron scattering (SANS) measurements are presented, using SWy-2 Wyoming bentonite clay in dry and water-bearing N2 and CO2 atmospheres. Oedometric SANS involves deforming a porous sample under uniaxial strain conditions with applied axial force and internal pore pressure control, and combines with SANS for in situ observation of pore structure evolution and interaction. Scattering from both interlayer (clay intra-aggregate) and free (interaggregate) pores is observed, showing decreasing pore size with dry consolidation and interactions between interlayer and free pore types with swelling and consolidation. Introduction of dry liquid CO2 at zero effective stress (axial stress minus pore pressure) produces large shifts in interlayer scatterers, but is reversible back to pre-CO2 levels upon decreasing pore pressure and increasing effective stress. Introduction of wet liquid CO2, conversely, produces large but irreversible changes in interlayer scatterers, which are interpreted to be the combined result of CO2 and H2O intercalation under hydrostatic conditions, but which diminish with application of effective pressure and consolidation to higher bentonite dry densities. Consideration of CO2 intercalation in smectite-bearing CO2 caprocks needs to include effects of both water and nonhydrostatic stress.
    Keywords bentonite ; carbon dioxide ; clay ; environmental science ; liquids ; nanopores ; neutron diffraction ; nitrogen ; porosity ; Wyoming
    Language English
    Dates of publication 2018-0219
    Size p. 3758-3768.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1520-5851
    DOI 10.1021/acs.est.7b04205
    Database NAL-Catalogue (AGRICOLA)

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  4. Article: Shales at all scales: Exploring coupled processes in mudrocks

    Ilgen, Anastasia G / David R. Cole / I. Yucel Akkutlu / Jason E. Heath / Kitty L. Milliken / L. Taras Bryndzia / Laura J. Pyrak-Nolte / Roberto Suarez-Rivera / Timothy J. Kneafsey / Yousif K. Kharaka

    Earth-science reviews. 2017 Mar., v. 166

    2017  

    Abstract: Fine-grained sedimentary rocks – namely mudrocks, including their laminated fissile variety — shales – make up about two thirds of all sedimentary rocks in the Earth's crust and a quarter of the continental land mass. Organic-rich shales and ... ...

    Abstract Fine-grained sedimentary rocks – namely mudrocks, including their laminated fissile variety — shales – make up about two thirds of all sedimentary rocks in the Earth's crust and a quarter of the continental land mass. Organic-rich shales and mudstones are the source rocks and reservoirs for conventional and unconventional hydrocarbon resources. Mudrocks are relied upon as natural barriers for geological carbon storage and nuclear waste disposal. Consideration of mudrock multi-scale physics and multi-scale spatial and temporal behavior is vital to address emergent phenomena in shale formations perturbed by engineering activities. Unique physical characteristics of shales arise as a result of their layered and highly heterogeneous and anisotropic nature, low permeability fabric, compositional complexity, and nano-scale confined chemical environments. Barriers of lexicon among geoscientists and engineers impede the development and use of conceptual models for the coupled thermal-hydraulic-mechanical-chemical-biological (THMCB) processes in mudrock formations. This manuscript reviews the THMCB process couplings, resulting emergent behavior, and key modeling approaches. We identify future research priorities, in particular fundamental knowledge gaps in understanding the phase behavior under nano-scale confinement, coupled chemo-mechanical effects on fractures, the interplay between physical and chemical processes and their rates, and issues of non-linearity and heterogeneity. We develop recommendations for future research and integrating multi-disciplinary conceptual models for the coupled multi-scale multi-physics behavior of mudrocks. Consistent conceptual models across disciplines are essential for predicting emergent processes in the subsurface, such as self-focusing of flow, time-dependent deformation (creep), fracture network development, and wellbore stability.
    Keywords carbon sequestration ; deformation ; engineering ; models ; permeability ; prediction ; radioactive waste ; shale ; waste disposal
    Language English
    Dates of publication 2017-03
    Size p. 132-152.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1792-9
    ISSN 0012-8252
    ISSN 0012-8252
    DOI 10.1016/j.earscirev.2016.12.013
    Database NAL-Catalogue (AGRICOLA)

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