VASYUGAN FORMATION IN THE UPPER PUR SUBFACIES: DEPOSITIONAL AND SEQUENCE STRATIGRAPHY MODELING (from Tyumen' SDB-6 drilling data)
P.A. Yan
Institute of Oil and Gas Geology, Siberian Branch of the RAS,
3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: Lithology, sequence stratigraphy, deposition environments, facies, Jurassic, West Siberia
Pages: 762-773
Abstract
The structure, composition, and deposition environments of Callovian-Oxfordian strata in the Nadym-Taz interfluve are analyzed on the basis of deep drilling data from the Tyumen' SDB-6. Depositional and sequence stratigraphy modeling reconstructs coastal and shelf conditions of the Vasyugan deposition that records sea-level fluctuations. The Vasyugan sequence revealed by sequence stratigraphy analysis of the Callovian-Oxfordian section is bounded by unconformities and includes a transgressive and a highstand systems tracts separated by a maximum flooding surface. The highstand systems tract is divided into a lower (early HST) and an upper (late HST) units corresponding to progradation-aggradational and progradational deposition, respectively.
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