Ewolucja przestrzeni porowej w piaskowcach górnego karbonu i dolnego permu Pomorza Zachodniego

Abstract

Evolution of pore space in the Upper Carboniferous and Lower Permian sandstones from Western Pomerania.S u m m a r y. The paper presents results of detailed research of pore space in the Upper Carboniferous and Lower Permian sandstones and those from the Upper Carboniferous/Lower Permian transitional section. This is followed by a preliminary assessment of reservoir properties against the background of diagenetic processes. The samples were collected from 11 boreholes. The research included standard petrological investigations supported by a digital image analysis of thin sections. Compaction and cementation were the main processes reducing porosity in all the sandstones. Cementation locally reduced primary porosity to approximately 80%. Compaction was much less active. The sandstones are characterized by primary and secondary porosity. Secondary intergranular as well as intercrystalline and intracrystalline porosity developed as a result of diagenetic dissolution of feldspar grains and cements. Variability of petrophysical parameters can be a result, among others, of lithological and facies development. Upper Carboniferous and Upper Carboniferous/Lower Permian sandstones show the best reservoir properties. Lower Permian sandstones are characterized by variable properties.