TY - JOUR

T1 - The type section of the Maikop Group (Oligocene-Lower Miocene) at the Belaya River (North Caucasus): Depositional environment and hydrocarbon potential

AU - Sachsenhofer, Reinhard F.

AU - Popov, Sergey V.

AU - Akhmetiev, Mikhail A.

AU - Bechtel, Achim

AU - Gratzer, Reinhard

AU - Groß, Doris

AU - Horsfield, Brian

AU - Rachetti, Alessandra

AU - Rupprecht, Bernhard

AU - Schaffar, Wolfgang B. H.

AU - Zaporozhets, Nina I.

PY - 2017/3

Y1 - 2017/3

N2 - The type section of the Oligocene to lower Miocene Maikop Group, considered the main source rock in the eastern Paratethys, has been studied using geochemical proxies to gain insights into depositional setting and hydrocarbon potential.The Maikop Group at the type section is about 600 m [2000 ft.] thick. Deposition commenced after a major late Eocene sea level drop and a subsequent early Oligocene sea level rise. The Maikop Group is composed mainly of carbonate-free pelitic rocks. Calcareous rocks are limited to the lower Oligocene succession, including the Polbian bed that forms a basin-wide marker horizon deposited during a time with significantly decreased salinity (“Solenovian event”). Anoxic conditions prevailed and were only interrupted for longer periods during deposition of the lower part of the lower Oligocene Pshekha Formation, the Polbian Bed and the lower Miocene Olginskaya Formation.TOC contents range up to 3.5 wt.%. HI values are typically below 300 mgHC/gTOC, but reach 420 mgHC/gTOC in black shales overlying the Polbian Bed (lower Morozkina Balka Fm.). Organic richness of this level, about 10 m [33 ft.] thick, is controlled by low salinity and high bioproductivity.The Maikop Group could generate approximately 2.0 tHC/m² surface area. A significant part (0.45 t/m²) comes from the lower Morozkina Balka Formation, which generates a high-wax paraffinic-naphthenic-aromatic mixed oil. The Pshekha, upper Morozkina Balka and Batalpashinsk Formations would generate low-wax oil or condensate. The hydrocarbon generation potential of the overlying formations is minor. Overall, the generation potential of the Maikop Group is surprisingly low.

AB - The type section of the Oligocene to lower Miocene Maikop Group, considered the main source rock in the eastern Paratethys, has been studied using geochemical proxies to gain insights into depositional setting and hydrocarbon potential.The Maikop Group at the type section is about 600 m [2000 ft.] thick. Deposition commenced after a major late Eocene sea level drop and a subsequent early Oligocene sea level rise. The Maikop Group is composed mainly of carbonate-free pelitic rocks. Calcareous rocks are limited to the lower Oligocene succession, including the Polbian bed that forms a basin-wide marker horizon deposited during a time with significantly decreased salinity (“Solenovian event”). Anoxic conditions prevailed and were only interrupted for longer periods during deposition of the lower part of the lower Oligocene Pshekha Formation, the Polbian Bed and the lower Miocene Olginskaya Formation.TOC contents range up to 3.5 wt.%. HI values are typically below 300 mgHC/gTOC, but reach 420 mgHC/gTOC in black shales overlying the Polbian Bed (lower Morozkina Balka Fm.). Organic richness of this level, about 10 m [33 ft.] thick, is controlled by low salinity and high bioproductivity.The Maikop Group could generate approximately 2.0 tHC/m² surface area. A significant part (0.45 t/m²) comes from the lower Morozkina Balka Formation, which generates a high-wax paraffinic-naphthenic-aromatic mixed oil. The Pshekha, upper Morozkina Balka and Batalpashinsk Formations would generate low-wax oil or condensate. The hydrocarbon generation potential of the overlying formations is minor. Overall, the generation potential of the Maikop Group is surprisingly low.

KW - Maikop

KW - Biomarker

KW - Paratethys

U2 - 10.1306/08051616027

DO - 10.1306/08051616027

M3 - Article

VL - 101.2017

SP - 289

EP - 319

JO - AAPG bulletin

JF - AAPG bulletin

SN - 0149-1423

IS - 3

ER -