Petroleum processes in the Palaeozoic-Mesozoic strata of the Grobla-Limanowa area (basement of the Polish Carpathians).

Abstract

Abstract:The geochemical characteristics of the Palaeozoic and Mesozoic strata of the basement of the Carpathian Foredeep depicted the Devonian and Carboniferous source rocks as the best source for hydrocarbon generation. Moreover, the Outer Carpathian sequence was geochemically characterized and proved capable of generating hydrocarbons. The oil-source rocks' correlations indicated that the source of the condensate accumulated in the Łąkta field, while oil in the Grobla field. Maturity modelling identified Devonian source rocks as they reached a late phase of the "oil window" and, locally, even the "gas window". The Carboniferous source rock was mature enough to start the generation processes. The generation started in the late Carboniferous, both in the Upper Silesian and Małopolska blocks. The main phase of the petroleum processes took place in late Neogene. The expulsion was observed only in the Devonian source rocks, and vertical migration by fault system in both blocks resulted in oil and gas accumulation in the Upper Jurassic carbonates and Upper Cretaceous sandstones. The petroleum modelling indicated the Devonian source for oil and gas fields in the study area. However oil-source rock correlation also suggests the presence of the Carpathian flysch source for hydrocarbons accumulated in the Łąkta field.

Genetic correlation of source rocks and natural gas in the Polish Outer Carpathians and Paleozoic–Mesozoic basement east of Kraków (southern Poland)

“…7). Re sults of the ad di tional anal y ses of these sam ples were pub lished ear lier by Kotarba et al (2004a) and Wróbel et al (2016).…”

“…9A) and pro duc tion in dex (PI) val ues up to 0.49 (Ta ble 1). The re sults of these and pre vi ous stud ies (Kotarba and Koltun, 2006;Wróbel et al, 2016) of pyrolytic (Ta ble 1; Ap pendix 2 and Fig. 10A), sta ble car bon iso tope (Ap pen dix 2 and Fig.…”

“…The geo chem i cal eval u a tion of the De vo nian and Mis sis sip pian strata was conducted based on the new re sults of cur rently ana lysed sam ples as well as on the Rock-Eval, sta ble car bon iso tope and n-alkane and isoprenoid dis tri bu tion anal y ses pub lished ear lier (Kotarba et al, 2004a, b;Wiêc³aw et al, 2011;Wróbel et al, 2016).…”

“…For ge netic in ter pre ta tion we also used the pre vi ous re sults of Rock-Eval-II py rol y sis anal y ses of 30 De vo nian sam ples from the Grobla-28, Rajbrot-1 and -2, Rajsko-3 and Waryoe-5 bore holes Wróbel et al, 2016), 59 Mis sissip pian sam ples from the £¹kta-2, Rajbrot-1, -2 and Strzelce Wielkie-1 bore holes (Matyasik et al, 2001;Kotarba et al, 2004a, b), 17 Mid dle Ju ras sic sam ples from the Tarnawa-1 and Strzelce Wielkie-1 (Kotarba et al, 2003) and 25 Up per Ju ras sic sam ples from Up per Ju ras sic strata col lected from the Grobla-S1, Grobla-W1, P³awowice-2 and Rajbrot-1 bore holes . In to tal, we used the re sults of 219 Rock-Eval py rol y sis mea sure ments for geo chem i cal char ac teris tics of the Pa leo zoic-Me so zoic base ment.…”

“…Wiêc³aw et al (2011) and Kotarba et al (2011) pointed to Up per De vo nian and Mis sis sip pian strata in the Up per Pa leo zoic suc ces sion of the Pol ish Carpathian base ment as hav ing the high est pe tro leum po tential, and Kotarba et al (2003) and Kosakowski et al (2012a) also iden ti fied the Mid dle Ju ras sic clays as rocks with the highest hy dro car bon po ten tial among the Me so zoic cover. The lo cation of pre vi ous geo chem i cal stud ies of source rocks in the Polish Outer Carpathians and the Pa leo zoic-Me so zoic base ment (Köster et al, 1998;Kotarba and Koltun, 2006;Kotarba et al, 2007Kotarba et al, , 2014Kosakowski et al, 2012a, b;Wróbel et al, 2016) is shown on Fig ure 2.…”