ON EXPLORATION POTENTIAL AND NEW OIL DISCOVERIES IN VOLKOV-GUROV HORST SYSTEM
FSBEI НРЕ USPTU, Ufa, the Russian Federation
LLC “BashNIPIneft”, Ufa, the Russian Federation
LLC “BashNIPIneft”, Ufa, the Russian Federation
The exploration maturity of the Republic of Bashkortostan in terms of the remaining petroleum potential is characterized among other features by the fact that the undiscovered oil and gas resources are confined to small traps with complex architecture.
Quite high hydrocarbon exploration potential of the Devonian sandstones as well as younger reservoirs is still related to the known extensive faulted zones. The paper focuses on one of such zones namely the Volkov-Gurov Horst System (VGHS).
The available geological and geophysical data suggest that this structural tectonic zone has additional potential for new oil discoveries. Fairly promising are not only the up thrown blocks of the VGHS which are characterized by very uneven drilling density, but also a deeper trend of anticlines along the downthrown wall of the fault to the South-East of it. Evidence thereof is provided by the geological setting of the two oil discoveries made in the Devonian sandstones allied to the VGHS play fairway.
The first discovery was made in the sandstones of Pashiy DI Fm. in the NE part of the study area within the Volkov-Gurov Horst System. Drilling data indicates that the top of the productive sandstone reservoir in well 37POD lies at -1951 m TVDss 52 m deeper than in well 231AMT (-1899 m) drilled in the up thrown horst block, the formation was water-bearing in that well. The fact that no oil was found in the shallow part of the reservoir may imply a 3-way dip closure sealed to a fault or impermeable tectonic barrier.
The second discovery is considerably to the SW on the Baskakov area of Novo-Uzhybashevskoe field. Well 7UZB penetrated top of Kynov Fm. at the shallowest depth of –1885 m, i.e. 7 and 13 m above the same formation penetrated in wells 475 (-1892 m) and 25UZB (-1898 m) accordingly which found oil.
The above mentioned arguments and the potential traps identified on the 2D seismic sections contribute to the additional exploration potential and commercial reserves of oil yet to be found in the sandstones of Kynov Dkn, Pashiy DI and Mullin DII formations not only on the up thrown fault blocks of the VGHS but also anticlines along the downthrown SE wall of the reverse fault bounding the graben in deeper-seated reservoirs.
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accumulation; deposit; faults; formation; horst; oil; petroleum potential; tectonically sealed trap; well; залежь; зона горстовидных поднятий; месторождение; нефтегазоностность; нефть; скважина; тектонически экранированная залежь; тектонические нарушения. DOI 10.17122/ogbus-2014-4-89-110 References to this article (GOST) Sattarov A.I., Belyalova A.S., Minkaev V.N. ON EXPLORATION POTENTIAL AND NEW OIL DISCOVERIES IN VOLKOV-GUROV HORST SYSTEM // Electronic scientific journal "Oil and Gas Business". 2014. №4. P.89-110. URL: http://ogbus.ru/issues/4_2014/ogbus_4_2014_p89-110_SattarovAI_ru_en.pdf