PETROPHYSICAL CHARACTERISTICS OF OIL- AND GAS-BEARING FLYSCH LITHOFACIES IN SELECTED WELL SECTIONS FROM THE OUTER CARPATHIANS (SOUTH POLAND)

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, SGEM Vienna GREEN Extended Scientific Sessions, www.sgemviennagreen.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-80-3 / ISSN 1314-2704, 2 - 5 November, 2016, Book 1 Vol. 4, 151-158pp, DOI: 10.5593/SGEM2016/HB14/S01.020

ABSTRACT

This study focused on petrophysical characteristics of the flysch sandstones and mudstones in the S-24 and S-26 well sections. The wells are located in the western part of the Polish Outer Carpathians (south Poland), in the Słopnice-Limanowa gas and oil field area. This region of the Polish Carpathians is considered to be prospective for unconventional oil and gas explorations. The petroleum potential in this area is associated with the sandstones and mudstones of Grybów Unit, which are located directly below the Magura thrust. A number of laboratory tests were performed with application of the mercury injection capillary pressure, X-ray diffraction and pulse decay permeability measurements. The used methods enabled the rock classification, detailed characterization of the pore space geometry and estimation of reservoir parameters. The analyses were conducted on core samples from S-26 and S-24 wells from the depth intervals of respectively 728 – 2243 and 1332 – 2150 meters. The results of applied methods imply that the studied flysch lithofacies from analysed wells reveal moderate values of the effective porosity (3 – 4% on average) and extremely low values of permeability (typically close to 0 mD). The analysis of mineralogical composition shows relatively high content of clay minerals (40% on average) and similar proportion of quartz and carbonates (25% on average). The applied methods results enabled to state that the analysed flysch rocks reveal features of tight gas and tight oil reservoir rocks.

Keywords: Outer Carpathians, flysch lithofacies, mercury porosimetry, porosity, permeability