FOSSIL-RELATED POROSITY SCANNING BY MEANS OF THE NUCLEAR MAGNETIC RESONANCE AND COMPUTED MICROTOMOGRAPHY - THE PERMIAN BRONSKO REEF CARBONATES, WESTERN POLAND

Fheed, A.; Krzyzak, A.; Lalowicz, Z.
Abstract:
Both complicated dissolution processes and different patterns of fossils’ distribution may be expected in carbonate hydrocarbon reservoirs. Therefore, this paper aims to precisely locate such places using few independent analytical tools. Five carbonate samples from the Permian Bro?sko Reef (Western Poland) were studied in a form of both thin sections and cylindrical core samples. The latter were subjected to Computed Microtomography (?CT) and Nuclear Magnetic Resonance (NMR) experiments. While the ?CT helped to preliminarily localize the most valid pores, the NMR provided significant information on petrophysical attractiveness of the reservoir. NMR research consisted of: (1) 9.4 [T], high-field, Zero Echo Time (ZTE) imaging; and (2) 0.05 [T], low-field, spatially resolved T2 profiling. As illustrated by the obtained results, joining together both low-field and high-field data, seems to be very desirable. The low-field approach showed the general trends in pore-size distribution, whereas the ZTE imaging allowed for the most permeable zones to be caught. Hence, numerous mouldic, cavernous and intraparticle porosity networks could have been located and investigated. Moreover, one more advantage of combining low- and high-field data should be considered. Although the high-field experiments may, in fact, yield better signal to noise ratio (SNR), they tend to show a relatively high vulnerability to generate the internal magnetic field gradients. The gradients may be present particularly when there is a significant difference between the magnetic susceptibility of the fossils and pore fluids, respectively. A much weaker magnetic field, utilized in the low-field NMR, enables omitting such signal disruptions, but this happens at the expense of method’s resolution. The exactness of such measurements can be additionally ameliorated by applying the spatially-resolved T2 experiments. Chosen slices of the same sample are then polarized separately and improve the accuracy of any experiment. It was hence shown, that a specific set of methods can significantly improve the effectiveness of the petrophysical analyzes, being a valid point of hydrocarbon prospection.
SGEM Research areas:
Year:
2017
Type of Publication:
In Proceedings
Keywords:
carbonates; porosity; Nuclear Magnetic Resonance; Computed- Microtomography; Zero Echo Time NMR imaging
Volume:
17
SGEM Book title:
17th International Multidisciplinary Scientific GeoConference SGEM 2017
Book number:
14
SGEM Series:
International Multidisciplinary Scientific GeoConference-SGEM
Pages:
667-676
Publisher address:
51 Alexander Malinov blvd, Sofia, 1712, Bulgaria
SGEM supporters:
Bulgarian Acad Sci; Acad Sci Czech Republ; Latvian Acad Sci; Polish Acad Sci; Russian Acad Sci; Serbian Acad Sci & Arts; Slovak Acad Sci; Natl Acad Sci Ukraine; Natl Acad Sci Armenia; Sci Council Japan; World Acad Sci; European Acad Sci, Arts & Letters; Ac
Period:
29 June - 5 July, 2017
ISBN:
978-619-7408-00-3
ISSN:
1314-2704
Conference:
17th International Multidisciplinary Scientific GeoConference SGEM 2017, 29 June - 5 July, 2017
DOI:
10.5593/sgem2017/14/S06.084
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