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| Titel |
Viscoelastic Anisotropic Constitutive Law for Rock Shales based on Laboratory Creep Experiments |
| VerfasserIn |
Maciej Trzeciak, Hiroki Sone, Marcin Dabrowski |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250140869
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| Publikation (Nr.) |
 EGU/EGU2017-4318.pdf |
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| Zusammenfassung |
| In situ stress prediction is critical for successful hydraulic fracturing and later exploitation of
an unconventional shale gas/oil reservoir. In order to provide stress models during and after
fracturing a reliable stress-strain constitutive law is needed. The most popular models used in
the petroleum industry take into account only elastic constitutive laws, which have the
assumption of no energy dissipation. As was shown by several authors (e.g. Warpinsky 1986,
Gunzburger&Cornet 2007, Sone&Zoback 2013, 2014) viscoelastic creep strain and stress
relaxation reach significant amounts in rock shales and should be considered in stress
modeling.
Viscoelastic functions needed for the constitutive law were obtained during creep
experiments on horizontal and vertical shale plugs. We were not in the possesion
of samples cut at 45˚ to bedding, and because of that the constitutive relation is
limited to the normal strains and stresses. During experiments two creep functions,
Ch(t)and Cv(t), and two hereditary Poisson’s ratio functions v12(t)and v13(t)were
measured.
In this paper we present laboratory procedures for creep tests, basic theory of anisotropic
(vertical transverse isotropy) viscoelastic constitutive modeling and a simple model of stress
relaxation after application of constant strain. |
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