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Wyszukujesz frazę "Baltic basin" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Comparison of joint sets orientation in the Lower Paleozoic shales exposed in Scania (SW Sweden) and concealed in N Poland : a multi-methodological approach
Autorzy:
Olkowicz, Marcin
Bobek, Kinga
Jarosiński, Marek
Pachytel, Radomir
Powiązania:
https://bibliotekanauki.pl/articles/2058695.pdf
Data publikacji:
2021
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
joint system
shale formations
Baltic Basin
photogrammetry
borehole scanner
Opis:
The Lower Paleozoic shales of SW Sweden and Eastern Pomerania (Poland) have a common history related to the depositional and tectonic evolution of the Baltic Basin. The major tectonic events are recorded, among others, as joints, which are either exposed in outcrops in SW Sweden or recognised in deep boreholes located in Pomerania. We present a comparison of the regional joint systems recognized by multiple methods in the studied region. In effect of a statistical compilation of measurements, five joint sets (named JS 1 to JS 5) were identified, traceable between Eastern Pomerania and SW Sweden. Our analysis showed a general consistency of joint set orientations, independent of their distance to the Tornquist tectonic zone passing through the study region. Three of the joint sets, JS 1 striking NNE, JS 2 striking WNW, and JS 3 striking NNW, are found to be the most frequent sets, occurring in most sites. Having more constant orientation, the JS 1 and JS 3 served as indicators of possible rotation of the tectonic block or stress field in the region. JS 1 and JS 2 are interpreted as an effect of late Carboniferous stress relaxation after Variscan collision, while JS 3 and the E–W striking JS 4 might be related to the Early Devonian Caledonian compressive stage.
Źródło:
Geological Quarterly; 2021, 65, 4; s. 258--275
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unconfined compressive strength of Lower Paleozoic shales from the Baltic Basin (northern Poland)
Autorzy:
Wojtowicz, Michał
Jarosiński, Marek
Pachytel, Radomir Władysław
Powiązania:
https://bibliotekanauki.pl/articles/2059581.pdf
Data publikacji:
2021
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
unconfined compressive strength
triaxial tests
empirical equations
shale reservoir
Baltic Basin
Opis:
Unconfined compressive strength of Lower Paleozoic shales from the Baltic Basin (northern Poland)Unconfined compressive strength (UCS) is one of the crucial parameters for geomechanical modelling of unconventional reservoirs useful for the design of hydraulic stimulation of hydrocarbon production. In spite of a large amount of UCS data collected from the Lower Silurian and Ordovician shale successions of the Baltic Basin (northern Poland), no comprehensive study on this subject has been published so far. Here, we compile the results of 247 single-stage confined compressive strength tests (CCST) provided by our industrial partner from four exploration boreholes. Based on the integration of these results with geophysical logging data, including dipole sonic logs, we derive empirical equations describing the relationship between UCS and Young’s modulus or sonic wave slowness. Considering the strong anisotropy of elastic properties in shales we have introduced different empirical equations for UCSv (vertical) and UCSh (horizontal), respectively perpendicular and parallel to bedding. The formula for UCSh is determined with less accuracy than for UCSv due to scarce laboratory tests with bed-parallel loading. Based on the empirical formula proposed, we have estimated the VTI-type of anisotropy to be in the range of 12–27%, depending on the lithostratigraphic formation. The results of our UCS estimations are compared with the results of multi-stage CCST from the adjacent borehole. Both confined tests yielded similar results for UCSv, with slightly higher values obtained from the multi-stage tests. In turn, a comparison of our solution with the results of true uniaxial compressive strength tests (UCST) for vertical samples from one of the studied boreholes revealed a significant discrepancy. The mean UCS results for shale formations from UCST are several times lower than those evaluated from the single-stage CCST. The usefulness of the results obtained for borehole breakout analysis is discussed.
Źródło:
Geological Quarterly; 2021, 65, 2; 65: 33
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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