Principal Components Analysis (PCA) and Cluster Analysis (CA) were applied for well log data derived from heterolithic intervals drilled in two boreholes (Mrowla-1 and Cierpisz-2) in the Miocene fill of the Carpathian Foredeep. Both boreholes penetrated similar basement elevations conductive for structural trapping of hydrocarbons in an overlying thin-bedded heterolithic reservoir, which produces gas in commercial quantities in one borehole. The PCA was used to reduce data space preserving sufficient amounts of parameters for a differentiation between thin layers of sandstones and mudstones and between gas- and water-saturated horizons. In both boreholes, the number of logs was reduced to four significant principal components (PCs). Differences between gas-saturated and water-saturated layers were found. CA was used for the classification and grouping of data according to natural petrophysical features of the analysed rocks. The group corresponding to gas-saturated zones was found in the Cierpisz-2 borehole. It is concluded that PCA and CA can provide useful information for a more reliable identification of gas-saturated horizons.
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Do rozpoznania elementów geomorfologii sejsmicznej na zdjęciach 3D osadów miocenu rejonu Dębica—Rzeszów—Sokołów Małopolski zapadliska przedkarpackiego wykorzystano szereg atrybutów sejsmicznych oraz przestrzenną wizualizację 3D. Uzyskane wyniki wskazują na obecność w utworach dolnego sarmatu dwóch systemów podmorskich koryt. Lokalnie rozwinięty system poprzeczny ma części proksymalne ukryte pod nasunięciem stebnicko-karpackim, a w kierunku NE łączył się z systemem osiowym o rozciągłości co najmniej 40 km i przepływie w kierunku E-SE. Koryta w obu systemach wykazują niską krętość, lokalnie anastomozującą lub meandrową geometrię, a ich szerokość wynosi 0,1-0,7 km. Wypełnienia koryt i ich amalgamaty, wykazują miąższości około 5-100 m i prawdopodobnie głównie heterolitowy charakter.
EN
A number of seismic attributes derived from five, partly overlapping 3D seismic datasets, were analyzed in order to get an insight into depositional elements of Miocene strata in SE part of the Carpathian Foreland Basin. Results point out the presence of two, major submarine channel systems in lower Sarmatian deposits. A locally developed transverse system has its proximal reaches hidden beneath the Stebnik-Carpathian thrust and it merges towards NE into an axial system, min. 40 km in extent, which drained to the E-SE. Channels show generally low sinuosity, locally anastomosing to meandering patterns, and their width varies between 0.1 and 0.7 km. Channels' fills, 5-50 m thick, are probably largely heterolithic in character.
A coarse diamictite (agglomerate) up to 34 m thick consisting mainly of angular basaltic lava clasts occurs within Tertiary terrestrial stratiform volcanic succession at Admiralty Bay, King George Island (South Shetland Islands, West Antarctica). At some sites, it interfingers with coeval basaltic lava flows. The coarse diamictite is interpreted as a lahar developed from low-maturity debris flows triggered either by volcanic eruptions or by less of stability by water-saturated weathering covers. Diamictites with predominantly rounded clasts, and sandstone -the products of short-lived short-distance reworking and sorting by running water, are subordinate.
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