DISTRIBUTIONS OF LIGHT HYDROCARBONS IN THE NEAR SURFACE ZONE OF THE MARGINAL PART OF THE CARPATHIAN FOREDEEP AND OUTER CARPATHIANS – CASE STUDY FROM SE POLAND

Gora, A.; Guzy, P.; Twarog, A.; Gorska-Mruk, E.; Sechman, H.
Abstract:
The paper presents the results of surface geochemical surveys carried out using "free gas method" in "Brzesko-Wojnicz" area in the SE part of the Poland. The surveys were conducted along 2 measurement profiles. A total of 341 soil gas samples were collected from 1.2 m depth below the surface. Maximum concentrations of CH4, total alkanes C2- C5, total alkenes C2-C4 reached: 27,1 vol.%., 45,3 ppm and 0,174 ppm, respectively. In total, in the analyzed area there are anomalous concentration of total C2-C5 alkanes (over 3? above calculated background mean) in 121 measurement points, comprising 9 zones ranging from 200 m to a 2 kilometres. Calculated hydrocarbon ratios CH4/?C2-C5 (C1/?C2-C5) and C2H6/C3H8 (C2/C3) allow to define the presence of compositionally diversified, deep hydrocarbon accumulations. The statistical parameters and histogram distributions of the above-mentioned ratios show dominance of condensate-oil character of deep-seated sources with the presence, in some samples, of the effects of current biochemical processes. The highest number of anomalies of total alkanes C2-C5 was determined over the Wojnicz thrust slice, particularly in the area of significant increase in thickness of autochthonous miocene sediments. The Wojnicz thrust slice is bordered to the south by the D?bno thrust slice, over where a decay of anomalous indications of total alkanes C2- C5 was observed. Besides, the thrust fault zone of this thrust slice collectively with the marginal part of the Outer Carpathian may create barriers to the potential migration and microseepage of hydrocarbons from deeper miocene horizons and from flysch sediments. The conducted analysis indicates that the number and distribution of surface geochemical anomalies point to the possibility of the occurrence of deep-seated accumulations, but the penetration of gas ingredients to the surface is determined predominantly by the tectonics of the area.
SGEM Research areas:
Year:
2017
Type of Publication:
In Proceedings
Keywords:
surface geochemical survey; soil gas; light hydrocarbons; Carpathian Foredeep; Poland.
Volume:
17
SGEM Book title:
17th International Multidisciplinary Scientific GeoConference SGEM 2017
Book number:
14
SGEM Series:
International Multidisciplinary Scientific GeoConference-SGEM
Pages:
601-608
Publisher address:
51 Alexander Malinov blvd, Sofia, 1712, Bulgaria
SGEM supporters:
Bulgarian Acad Sci; Acad Sci Czech Republ; Latvian Acad Sci; Polish Acad Sci; Russian Acad Sci; Serbian Acad Sci & Arts; Slovak Acad Sci; Natl Acad Sci Ukraine; Natl Acad Sci Armenia; Sci Council Japan; World Acad Sci; European Acad Sci, Arts & Letters; Ac
Period:
29 June - 5 July, 2017
ISBN:
978-619-7408-00-3
ISSN:
1314-2704
Conference:
17th International Multidisciplinary Scientific GeoConference SGEM 2017, 29 June - 5 July, 2017
DOI:
10.5593/sgem2017/14/S06.076
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