Zasoby ropy naftowej w III piaskowcu ciężkowickim w złożu Osobnica (jednostka śląska, polskie Karpaty zewnętrzne)— uwarunkowania sedymentologiczne

Paweł Lis


Oil resources of the third Ciężkowice sandstone in the Osobnica oilfield (Silesian Unit, Polish Outer Carpathians) — sedimentological characteristic.
Summary. The study area is located in the central part of the Polish Outer Carpathians in the vicinity of Jasło. Petroleum reservoir described here is the third Ciężkowice sandstone (Upper Paleocene), composed of channel fill and depositional lobe succession. The Osobnica field is a part of an ancient deepwater fan system, referred to as the Eastern Fan. Within this system, seven sandstone packages interbedded with mudstone/fine sandstone deposits were recognized. The first, second and the third package are characterized by coarsening- and thickening-upward trends, and are interpreted as depositional lobes. The overlying four packages, each roughly 40 m thick, show upward fining and thinning and are interpreted as channel fill deposits. In the Osobnica field, the total resources are calculated at about 491 500 tons, of which some 352 600 tons of oil were exploited until 2002. Map of resource arrangement and structural modelling have indicated that the main factor controlling the distribution of hydrocarbons in the Osobnica field is the shape of the structure, whereas facies development played a subordinate role. The main part of oilfields is in the SE elevated part of the Osobnica anticline. Oil accumulated in both channel and lobe deposits, although channel fills appear to be slightly more oil prone.

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