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Skały silikoklastyczne triasu i jury niecki łódzko-miechowskiej w aspekcie rozwoju ich przestrzeni porowej

Kuberska Marta, Kozłowska Aleksandra, Wołkowicz Krystyna

Przegląd Geologiczny

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2023

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Vol. 71, nr 4

212--218

EN

Triassic and Jurassic siliciclastic rocks from boreholes drilled in the Łódź and Miechów troughs to the SW of the Mid Polish Anticlinorium have been subjected to petrologic studies. The are represented by claystones, mudstones, sandstones, and less frequently by conglomerates. The studies shows that the filtration and reservoir properties of the Triassic deposits not good due to diagenetic processes (compaction, cementation, replacement, dissolution). Only some Lower Triassic sandstones, occurring among others, as intelayers, display increased values of permeability and porosity (to about 27 vol. %). The best properties are display ed by sandstones from the Brzegi IG 1 borehole, in which macropore intergranular space is present. The Lower Jurassic rocks are characterized by the best properties within the Jurassic complex. They show increased values of mostly secondary porosity, which results from the dissolution of grains and cements. The pore space is developed homogenously. It has a micropore character in the Middle and Upper Jurassic deposits.

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REE-bearing minerals in sediment-hosted stratiform pyrite mineralization zones of the Wiśniówka area (Holy Cross Mts., Poland)

Migaszewski Zdzisław M., Gałuszka Agnieszka, Zielińśki Grzegorz

Geological Quarterly

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2023

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Vol. 67, No. 2

art. no. 17

EN

There are two arsenical pyrite (As-FeS2mineralization zones cropping out in the Podwiśniówka and Wiśniówka Duża quarries where quartzites and quartzitic sandstones have been extracted for over a century. A large amount of pyrite in the Wiśniówka siliciclastics is unusual in the hard rock mining throughout the world. The pyritiferous beds contain a variety of REE-bearing minerals, including a crandallite series of aluminum-phosphate-sulfate (APS) minerals, e.g., predominant goyazite SrHAl3[(PO4)2(OH)6] with subordinate gorceixite BaHAl3[(PO4)2(OH)6] and very occasional crandallite CaHAl3[(PO4)2(OH)6]. By contrast, the other REE-phosphate minerals, e.g., xenotime YPO4, bur particularly monazite CePO4 occur in a lesser amount. Goyazite prevails somewhat in the Podwiśniówka beds whereas xenotime in the Wiśniówka Duża beds. Of the other REE-bearing minerals, bastnäsite REECO3(F,OH), florencite (REE)Al3(PO4)2(OH)6 and synchysite CaCe[CO3]2F occur in trace amounts. Interestingly, the quite common phosphate minerals, i.e., wavellite (Al.3[(OH,F)3|(PO4)2]×5H2O and variscite Al[PO4]×2H2O) are depleted in REEs with only Ce attaining 0.09 wt.% as documented by an electron-probe microanalysis. In contrast to quartzites/quartzitic sandstones, carbonaceous clayey-silty shales and bentonites/tuffites are distinctly enriched in REE-bearing minerals. This diversity is also mirrored in the mean total REE concentrations varying from 204 to 314 mg/kg, in clayey-silty shales and bentonites, attaining 457 mg/kg in some Podwiśniówka shale beds. Results of this and the previous petrographic, mineralogical and geochemical studies have indicated that REE-bearing minerals formed generally along with As-rich pyrite, nacrite/dickite and probably TiO2 polymorphs as a result of multiphase hydrothermal vent activity that took place in the Wiśniówka Late Cambrian sedimentary basin. This evidence is also backed up by the values of LREENASC/HREENASC (1.44–1.75) and Eu/EuNASC (1.24–1.30) coefficients in the clayey-silty shales. This positive Eu anomaly (31.20) points to the formation of REE-bearing minerals in a reducing environment.

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Results of the comprehensive interpretation of well logs in carbonate and siliciclastic rocks – similarities and differences in the case studies of selected formations

Waszkiewicz Sebastian, Alvarez Ronal Barcala, Jarzyna Jadwiga

Geology, Geophysics and Environment

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2019

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Vol. 45, no. 3

163--182

EN

This paper was made using geological and well logging data from the Cuban oilfield area and the Polish Carpathian Foredeep gas deposit to compare the interpretation process and underline similarities and differences between data analysis from two reservoir rocks of different lithology. Data from conventional hydrocarbon deposits, i.e. the Mesozoic Cuban carbonate formation and Miocene shaly-sandy sediments were processed and interpreted using Techlog (Schlumberger Co.) software. Selected approaches were used to determine the step by step volume of shale, total and effective porosity, water/hydrocarbon saturation (Quanti) and for the comprehensive interpretation of well logs (Quanti Elan). Brief characteristics of the carbonate and siliciclastic formations were presented to indicate that the interpretation methodology oriented to the determination of petrophysical properties depends strongly on the type of reservoir. Cross-plots were presented for primary mineral composition recognition, determination of m exponent and resistivity of formation water in the Archie equation. Effective intervals for the carbonate reservoir were calculated according to the Cumulative Hydrocarbon Column methodology. Finally, the results of the interpretation of well logs were presented as continuous curves of mineral composition, including shaliness, porosity and hydrocarbon saturation. The conclusions included recommendations for the effective comprehensive interpretation of well logs in the carbonate and siliciclastic reservoirs.

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Wstępne wyniki oceny współczynnika przewodności cieplnej skał klastycznych na podstawie składu mineralnego

Przelaskowska A., Gąsior I., Drabik K.

Prace Naukowe Instytutu Nafty i Gazu

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2016

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nr 209 wyd. konferencyjne

651--654

PL

Celem pracy było określenie współczynnika przewodności cieplnej skał na podstawie składu mineralnego. Przetestowano wybrane modele matematyczne uwzględniające objętościową zawartość poszczególnych minerałów wraz z odpowiadającymi im współczynnikami przewodności cieplnej, a następnie porównano otrzymane wyniki z danymi laboratoryjnymi. Zaobserwowano znaczący wpływ litologii na wybór odpowiedniego modelu.

EN

The aim of the presented work was the determination of the thermal conductivity of rocks based on their mineral composition. Mathematical models based on volumetric fractions of rock components and their thermal conductivities were introduced and the obtained results were compared with laboratory data. A significant impact of lithology on the choice of an appropriate model was observed.

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Petrographic characteristic of the Middle Miocene sediments in the Ukrainian segment of the Carpathian Foredeep

Kuberska M., Kozłowska A., Lis P.

Annales Societatis Geologorum Poloniae

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2011

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Vol. 81, No 3

351-361

EN

The Upper Badenian and Sarmatian strata from thirteen wells situated in the Ukrainian part of the Carpathian Foredeep were petrographically analysed. The studies were performed using a polarizing microscope (standard petrographic analysis, cathodoluminescence studies – CL), SEM and EDS ISIS. Moreover, the XRD was conducted, isotopic ratios of light isotopes of carbon and oxygen in carbonate cements determined, and porosimetric measurements performed on selected samples of sandstones. Claystones, mudstones and sandstones were distinguished among the studied rocks. The sandstones were examined in great detail. The following sandstone varieties were distinguished: unequal-grained, fine-, and rare medium-grained. They are classified as arenites and subarkosic, locally sublithic and quartz wackes. Quartz and feldspars (K-feldspars, plagioclases) are main components of the grain fabric of mudstones and sandstones. Rock fragments (of sedimentary, less common effusive rocks, individual fragments of granitoids and/or metamorphic rocks) occur in the sandstones, too. Micas (mainly muscovite), glauconite, rare bioclasts, fine plant remnants, and accessory zircons are present. The cement is composed of allogenic-and authigenic clay minerals (illite, smectite, chlorites, kaolinite), carbonates (Fe-calcite, dolomite, ankerite), authigenic quartz and, sporadically, authigenic feldspar and anhydrite. Effects of diagenetic processes, mainly of mechanical compaction, cementation, dissolution, and less significant replacement and alteration have been recorded in the sediments studied. The compaction and cementation have almost an equal influence on reduction of porosity and permeability of the analysed rocks. Abundant sandstone packages, however, display very good reservoir properties (porosity amounts to 30%, and permeability is over 200 mD).