Estonian Journal of Earth Sciences, 2015, 64, 3, 199–217 doi: 10.3176/earth.2015.27 Reservoir quality and petrophysical properties of Cambrian sandstones and their changes during the experimental modelling of CO2 storage in the Baltic Basin Kazbulat Shogenova, Alla Shogenovaa, Olga Vizika-Kavvadiasb and Jean-François Nauroyb a Institute of Geology at Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia;
[email protected] b IFP Energies nouvelles, 1 & 4 avenue de Bois-Préau 92852 Rueil-Malmaison Cedex, France Received 5 January 2015, accepted 20 April 2015 Abstract. The objectives of this study were (1) to review current recommendations on storage reservoirs and classify their quality using experimental data of sandstones of the Deimena Formation of Cambrian Series 3, (2) to determine how the possible CO2 geological storage (CGS) in the Deimena Formation sandstones affects their properties and reservoir quality and (3) to apply the proposed classification to the storage reservoirs and their changes during CGS in the Baltic Basin. The new classification of the reservoir quality of rocks for CGS in terms of gas permeability and porosity was proposed for the sandstones of the Deimena Formation covered by Lower Ordovician clayey and carbonate cap rocks in the Baltic sedimentary basin. Based on permeability the sandstones were divided into four groups showing their practical usability for CGS (‘very appropriate’, ‘appropriate’, ‘cautionary’ and ‘not appropriate’). According to porosity, eight reservoir quality classes were distinguished within these groups. The petrophysical, geochemical and mineralogical parameters of the sandstones from the onshore South Kandava and offshore E6 structures in Latvia and the E7 structure in Lithuania were studied before and after the CO2 injection-like alteration experiment.