A number of oil‐ and gasfields have recently been discovered on the continental shelf of Southern Vietnam, the largest of which is White Tiger. The main pay‐zone in this field is in the basement, which is composed of granites and granodiorites, lithologies which are found in the basement elsewhere on the shelf. The granites have undergone severe alteration as a result of tectonic, hydrothermal and surface weathering processes. Reservoirs are related to cavernous fracture porosity in deep basement zones, and to “porous cavernous” fracturing at more shallow levels. Total reservoir thickness exceeds 1 km, and the oil‐water contact has not yet been located. Flow‐rates reach 2,000 cu. m/d. Drilling data indicates that the granitoids are overlain by argillaceous‐terrigenous rocks of Oligocene and younger ages which have a thickness of 2.5‐4.4 km (up to 8 km in places, according to seismic data). Source rocks are mostly early Oligocene argillites, from which oil probably migrated into upthrown basement blocks.

The article considers various types of non-anticlinal traps of the Yamal Peninsula of Western Siberia. The task is to establish the features of their formation and structure. Gas and gas condensate deposits were allocated in the Akhskian formation of the Neocomian section, associated with wedge-shaped traps (Bovanenkovsky, Kharasaveysky fields). This type of lithologically-shielded traps was formed due to clastic material entering the territory of the Yamal Peninsula from the East Siberian Platform, the Yenisei Ridge (from the east) and the Ural Mountains (from the west). Sand and clay material accumulated along the path of underwater hills, where wedging zones formed. Traps of various types are developed in the Jurassic deposits of the region. Traps of tectonically shielded type are formed in areas of the active influence of discontinuous disturbances on the structure of the section (for example, on the Nurminsky Swell). Lithologically-shielded traps are formed on the slopes of the erosive remnants of the paleorelief in zones of terrigenous horizons wedging. Such traps are also formed in zones of their screening by the surface of the pre-Cretaceous erosion. The considered examples made it possible to establish the confinement of various types of traps to the sediment section and their distribution over the area of ​​the Yamal region.

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According to the oil and geological zoning, the water area of the Kara Sea, including the Ob and Taz Bays, is located on the border of three oil and gas-bearing regions: Yamal, Gydan and Nadym-Purskaya, having different characteristics of oil and gas potential by section and by area. As a result of geological exploration carried out in the water area and on the adjacent land, a wide age range of oil and gas potential was revealed. Seven fields have been discovered in the waters of the Yuzhno-Kara NGO: six gas condensate fields in Cretaceous Cenomanian-Albian deposits and one oil and gas condensate field in Cretaceous and Jurassic deposits. Large gas condensate fields have been explored in the Ob and Taz bays in the Cenomanian-Alb-Apt complex. The water area of the lips is one of the most important areas in terms of the growth of economically viable natural gas resources. According to the research results, it has been established that the UV potential of the Jurassic and Lower Cretaceous complexes of the Ob and Taz Bays is characterized as highly promising. Keywords: Kara Sea; shelf; cretaceous and jurassic deposits.

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