Microstructural Evolution of Porosity and Stress During the Formation of Brittle Shear Fractures: A Discrete Element Model Study

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dc.citation.firstpage2228en_US
dc.citation.issueNumber3en_US
dc.citation.journalTitleJournal of Geophysical Research: Solid Earthen_US
dc.citation.lastpage2245en_US
dc.citation.volumeNumber123en_US
dc.contributor.authorLongJohn, Tamunoisoalaen_US
dc.contributor.authorMorgan, Julia K.en_US
dc.contributor.authorDugan, Brandonen_US
dc.date.accessioned2018-09-11T20:40:45Zen_US
dc.date.available2018-09-11T20:40:45Zen_US
dc.date.issued2018en_US
dc.description.abstractBrittle fracturing in rocks is a progressive process involving changes in stress, strain, and porosity. Changes in these properties occur heterogeneously within a rock and are manifest at the grain scale, which is difficult to observe directly in the laboratory or the field. This study uses the discrete element method to show that fractures correspond to zones of generally lower stresses, higher porosity, and highly localized dilation and distortional strain. Using the discrete element method, we conducted numerical biaxial experiments at different confining pressures to probe the internal conditions of a low cohesive sandy sediment numerical analog. When compression begins, the stresses within the sandy sediment are relatively homogeneous with anastomosing stress chains. At yield stress, when the confining pressure is relatively low, multiple dilational bands start to open. At peak stress, high‐magnitude stress chains localize adjacent to the developing shear band and distortion is evident. Postpeak stress, through‐going shear fractures are fully developed. High stresses are transmitted across the fracture where porosity is low through a network of particles in contact. With increasing confining pressure, distortion is favored over dilation during deformation. Also, the number of particles that define the width of a stress chain across a shear fracture, and the steepness of the fracture, increases. Our results can be applied to understanding stress conditions of field samples, and in constraining rock property changes during reservoir modeling of fractured reservoirs.en_US
dc.identifier.citationLongJohn, Tamunoisoala, Morgan, Julia K. and Dugan, Brandon. "Microstructural Evolution of Porosity and Stress During the Formation of Brittle Shear Fractures: A Discrete Element Model Study." <i>Journal of Geophysical Research: Solid Earth,</i> 123, no. 3 (2018) Wiley: 2228-2245. https://doi.org/10.1002/2017JB014842.en_US
dc.identifier.doihttps://doi.org/10.1002/2017JB014842en_US
dc.identifier.urihttps://hdl.handle.net/1911/102500en_US
dc.language.isoengen_US
dc.publisherWileyen_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.titleMicrostructural Evolution of Porosity and Stress During the Formation of Brittle Shear Fractures: A Discrete Element Model Studyen_US
dc.typeJournal articleen_US
dc.type.dcmiTexten_US
dc.type.publicationpublisher versionen_US
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