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| Titel |
Characterizing petrophysical properties of carbonate rocks using nuclear magnetic resonance and spectral induced polarization |
| VerfasserIn |
Fan Zhang, Chi Zhang, Eugene Rankey |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250135162
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| Publikation (Nr.) |
 EGU/EGU2016-15995.pdf |
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| Zusammenfassung |
| Unlike sandstones, with well-characterized correlations between porosity and permeability,
carbonate rocks are well known for their highly complex petrophysical behaviors due to their
intrinsically heterogeneous pore shape, pore size, and pore distributions and connectivity. The
characterization of petrophysical properties of carbonate rocks, including rock properties
and rock-fluid interactions, remains big challenges. This laboratory study focuses
on integrating two geophysical methods: nuclear magnetic resonance (NMR) and
spectral induced polarization (SIP) to determine porosity, pore size distribution,
and permeability of carbonate rocks. NMR measures the relaxation of hydrogen
nuclei at pore scale. Samples with different pore structures saturated by fluids have
molecular relaxation responses to the external magnetic field which could generate
various NMR signals. Permeability estimation from NMR in siliciclastic rocks is
routine, however, is problematic in carbonates. SIP determines complex resistivity
of a sample across a wide range of frequency and is sensitive to variations in the
properties of solid-fluid and fluid-fluid interfaces in porous media. Previous studies
investigated the relationships between permeability and parameters derived from SIP
data, but are restricted to narrow lithology range. Our study used carbonate core
samples from three depositional environments: tidal zone, shallow marine, and
platform/reef margin of an atoll. Samples were fully saturated by water for T2 relaxation
measurements and complex conductivity measurements at low frequencies. We compare the
pore volume to surface area ratio measured from NMR and SIP and assess the
applicability of established petrophysical models to estimate permeability from
NMR and SIP data. We hope to build a relationship between NMR signals, SIP
responses and petrophysical properties in carbonate rocks. The results could also
provide new data and help further understand the unique and complex pore structure
of carbonates, which would lead to better constrained interpretation of field data. |
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