COMPARATIVE ANALYSIS OF MEASUREMENTS AND ESTIMATION OF PERMEABILITY OF SHALES IN SELECTED WELL SECTIONS FROM BALTIC BASIN (NORTHERN POLAND)

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-57-5 / ISSN 1314-2704, June 28 - July 6, 2016, Book1 Vol. 3, 769-776 pp

ABSTRACT
Permeability is one of the key petrophysical parameters characterizing reservoir rocks. This study has been focused on comparative analysis of measurements and estimation of permeability of Silurian and Ordovician gas-bearing shales from three wells located in the Baltic Basin. Permeability was determined by using three methods. In the first method using the pulse-decay technique, 19 samples from selected boreholes were measured in the range of 10 nD to 0.5mD. The second method - CPMG provided results from nuclear magnetic resonance (NMR). This technique is based on the relation between transverse relaxation time and porosity. The results obtained from NMR measurements were calculated and calibrated using two commonly applied models of permeability: the Free Fluid model (Timur-Coates model) and the Schlumberger Doll Research Center model. In the last method, permeability measurements from Mercury Intrusion Capillary Pressure (MICP) were achieved. Summary of measurements and calculations of permeability obtained by three different approaches and their correlation allowed for the complex permeability characteristics of gas-bearing shales from the Baltic Basin.

Keywords: Baltic Basin, shales, pulse-decay method, NMR permeability models, MICP