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| Titel |
Application of magnetic proxies in reservoir characterization: a case study from the North German Basin |
| VerfasserIn |
Robert Scholger, Norbert Schleifer, Nina Gegenhuber, Veronika Rieckh |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093993
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| Publikation (Nr.) |
 EGU/EGU2014-9257.pdf |
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| Zusammenfassung |
| Porosity and permeability are key parameters for hydrocarbon reservoir characterization, but
measurements are time consuming and expensive, and the demand for petrophysical proxies
for these parameters is growing. In this study, the focus was laid on magnetic properties and
their links with rock facies. Magnetic proxies can provide information about the
concentration, grain size and type of magnetic minerals in soils and rocks. They are
commonly used in environmental screening and mineral prospecting, but their potential for
reservoir characterization is not yet fully understood.
Sandstone samples from two elder drill cores from the North German Basin
(Rotliegend) were examined. Natural remanent magnetization, frequency dependent
magnetic susceptibility and anisotropy of magnetic susceptibility were measured
before and after salt extraction, and the results were correlated with porosity and
permeability. Acquisition of isothermal remanent magnetization and Curie point
determinations were used to characterize the magnetic mineralogy in respect of the rock
facies.
Three ferr(o)magnetic minerals could be identified in the samples: magnetite,
hematite and goethite. The occurrence of these three minerals was strongly dependant
on the rock facies. Samples, which were characterised as aeolian mudflats, low
energetic fluvial deposits and lake sediments typically yielded a significant magnetic
anisotropy and relatively higher susceptibility values, whereas porosity and permeability
was low. Hematite was found to be the most important magnetic mineral in these
facies types. Contributions from goethite and a paramagnetic phase, probably illite,
were also observable in most samples. In contrary, samples characterised as dry
sandflats, damp sandflats and aeolian dunes showed elevated porosity and lower
magnetic susceptibility values. Despite the lower bulk susceptibility values, the
magnetic properties pointed towards magnetite as main magnetic mineral in these
samples.
The relationship between the studied magnetic and reservoir parameters was strongly
dependent from the facies types. In general, porosity and permeability showed best
associations with bulk magnetic susceptibility, magnetic foliation and the magnetic
anisotropy shape parameter. |
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