... horizons. The Purpei–Vasyugan area is divided into three subareas according to the structure of the Vasyugan Formation including the petroliferous horizon Yu 1 . Transition zones have been recognized between the Vasyugan Formation and the bordering Abalak, Tatar, and Naunak formations along the western...

..., Tyumen’, Naunak, and Mar’yanovka Formations are described from a detailed comprehensive core analysis and log data. The depositional environment for these sediments was predominantly continental. There is evidence for short transgressions in the Ilan (Lower Toarcian) and Peshkovo (Upper Toarcian...

...Fig. 5. Ichnofossil distribution over different types of the Callovian–Oxfordian section of the West Siberian basin. A , Vasyugan Formation, Upper Pur facies subregion; B , Vasyugan Formation, Ob’–Tara and Ob’–Agan subregions; C , Abalak Formation; D , Naunak Formation; E , Tochino...

..., 1970 ). Another reason that makes this area interesting theoretically and practically is that it is in the zone of transition from the essentially marine Vasyugan Formation to the essentially continental Naunak Formation. The boundary between the formations is drawn in different parts...

... Formation; marginal-marine and continental sediments in the lowermost sections of the Naunak and Tyazhin Formations. Shale-dominated successions of the Golchikha, Abalak, Danilovo, and Tochin Formations, as well as the Lower Vasyugan Subformation developed to form a regional cap rock ( Kontorovich et al...

... Formation. In the southeast this interval is characterized by the predominantly terrestrial Naunak Formation. A distinctly distinguishable Pakhomovo Member ( J 2 0 bed), interpreted as a basal part of a transgressive cycle, lies in the base of the Vasyugan, Abalak and Tochino Formations...

... XII, XIII Sil’ga, Azharma; Naunak Formation XIV Chulym–Taseeva; Tyazhin Formation Most of the Oxfordian ammonites are from the Danilovskoe, Abalak, and Vasyugan Formations. The Oxfordian Stage in the Danilovskoe Formation consists of finely washed mudstone-like glauconitic clays...

... and Naunak Formations); the Abalak clays continued to accumulate in the west of the lowland. The Oxfordian-Tithonian transgression in the east and the Oxfordian-Kimmeridgian regression in the west may have peneplained the topography and prepared culmination in the plate’s tectonic evolution associated...

... of probabilistic distribution ( Figure 4B ), indicating Jubilee is more likely to be a combination trap with upslope faulting being an important factor in trap formation. Dailly et al. (2012) noted that the Turonian reservoirs appear to be trapped against a downthrown fault toward the northeast. Faulting seems...

... of the facies transition of the Vasyugan Formation into the continental Naunak Formation and thus loses its confining-bed properties, which permits fluids to migrate from the Bazhenov Formation into underlying sediments [ 13 ]. Analysis of hydrogeological data suggests the existence of vertical water cross...

.... The structural and lithological models were based on maps of lithotypes and structural maps on the roof of the pre-Jurassic basement, the Urman, Togur, Peshkov, and Salat Formations, the Lower Tyumen subformation, the Tyumen, Naunak (Vasyugan), Bazhenov, Tar, Alym, Pokur, Kuznetsov, Ipatov and Talit Formations...

... Formations (K 1 ); 6–7, Bazhenovo (plus Georgievka) and Vasyugan (Naunak) Formations (J3); 8, Tyumen’ Formation (J 1–2 ); 9, pre-Jurassic basement (PZ). ...

... ). The thickness of the f -zone in the explored zone is 44.8 m. Stratigraphic position. The uppermost Bathonian–Callovian; lower part of the Danilov, Abalak, Vasyugan, Naunak, Tochino—lower Sigov Formations (see Fig. 4 ). Late Callovian ammonites identified by S. V. Meledina as (?) Longaeviceras sp. ind...

... , foraminifers; 9 , spore and pollen assemblages; 10 , age. For other symbols see Fig. 1 . Abbreviations for formation names: gl, Golchikha; jan, Yanovstan; sg, Sigovaya; tch, Tochinka; ab, Abalak; bg, Bazhenov; gr, Georgievka; mr, Mar’yanovka; mks, Maksimkin Yar; vs, Vasyugan; nn, Naunak; tzh, Tyazhin; bgn...