DOI: 10.5593/SGEM2015/B11/S6.099


L. Kaczmarek, M. Maksimczuk, T. Wejrzanowski, A. Krzyzak
Thursday 6 August 2015 by Libadmin2015

References: 15th International Multidisciplinary Scientific GeoConference SGEM 2015, www.sgem.org, SGEM2015 Conference Proceedings, ISBN 978-619-7105-31-5 / ISSN 1314-2704, June 18-24, 2015, Book1 Vol. 1, 779-786 pp

This paper concerns the characterization of porosity in carbonate reservoir rock provided by high-resolution x-ray computed microtomography (µCT) and nuclear magnetic resonance (NMR). The resulting pixel size of the µCT image was in the range 5 to 27 µm, which enabled satisfactory visualization of the internal carbonate rock structure and quantitative characterization.NMR analysis provides a detailed description of the porosity samples, with analysis of the influence of water on the results. Study of the first samples series made by μCT imaging with pixel size of 27 microns showed a compact and relatively homogeneous structure. Nonetheless, μCT testing of the second samples series, with pixel size of 4 microns, revealed heterogeneity in the structure and porosity. Heterogeneity of the tested material was confirmed by the NMR analysis. The porosity determined by μCT fluctuates around 0.54%. Total porosity of the dried sample, evaluated by NMR, is on average 1.68% and for full water saturated 2.72%. Differences in μCT and NMR results were caused by the presence of μCT-undetectable pores. Information about minimum pore size, which is obtained by μCT, allows one to determine the ranges of pore size detected by NMR. Based on these data NMR calibration can be done. A further advantage of μCT is its ability to distinguish organic matter and empty pores. Due to the use of μCT pore size determination in the NMR method and the possibility of porosity verification, it can be concluded that these two techniques are complementary and provide an opportunity to obtain a precise characterization of tested samples.

Keywords: carbonate reservoir rock, computed microtomography, nuclear magnetic resonance