PRZESTRZEŃ POROWA PIASKOWCÓW JURY DOLNEJ W REJONIE BEŁCHATOWA

Abstract

PORE SPACE IN LOWER JURASSIC SANDSTONES OF THE BEŁCHATÓW REGIONAbstract. Lower Jurassic sandstones from eight boreholes (Florentyna IG 2, Gomunice 13, Jeżów IG 1, Kalisz IG 1, Niechmirów IG 1, Zakrzyn IG 1, Zamoście 1 i Zaosie 2) of the Bełchatów region were studied for petrography and petrophysical properties. The following research methods were used: polarizing microscope observations (PL), cathodoluminescence studies (CL), scanning electron microscope (SEM) investigations and energy dispersive spectrometer studies (EDS ISIS), X-ray diffraction analyses (XRD) and laboratory petrophysical examinations. The sandstones are represented by very fine- to medium-grained quartz arenites and wackes. The main component of the grain framework is quartz. Feldspars, lithoclasts and micas occur in minor proportions. The sandstone is bonded predominantly by matrix accompanied by quartz, siderite (and other minerals of the siderite–magnezite series), Fe-dolomite/ankerite and kaolinite cements. The rocks are characterized by good and very good filtration properties. Porosity of the sandstones, very often exceeds 15%, and permeability ranges from 0.1 to 1361.7 mD. Pore space parameters measured in porosimeter show the following trend: dynamic porosity factor: 4.7–30.0%, average amount of pores >1 μm: 5–99%, threshold diameter: 0.2–64.0 μm and hysteresis: 2–87%.