LOWER-MIDDLE CAMBRIAN REEF BARRIER IN THE NORTHERN SIBERIAN PLATFORM AS A TARGET OF PRIMARY EXPLORATION FOR OIL AND GAS

Yu. A. Filiptsov, N. V. Melnikov, A. S. Efimov, V. I. Valchak, N. A. Goryunov, A. A. Evgrafov, E. V. Smirnov, V. A. Scherbakov, V. Yu. Kultyshev

The conjunction zone of the Kureika syneclise eastern edge and Anabara anteclise in the northern Siberian Platform is characterized by two regional seismic lines of submeridional orientation and cross cuts to them. Profiles have been made with the use of federal funds. Main section types of the Cambrian and the separating rift are observed in the interfluve of the Moyero-Kotui and Nizhnyaya Tunguska rivers on several profi les and south-eastern cross cuts to them. The obtained results showed that the reef barrier is confi ned to a flexural fold bend where Vendian deposits plunge sharply and thicknesses of Lower-Middle Cambrian ones grow. In the plunging part of the Kureika syneclise the barrier bodies ajoin southerly to the development field of carboniferous-argillaceous-carbonate rocks of the Kuonamka Formation. West of the Tura village the position of the reef barrier as well as the Kuonamka Formation has not been studied. The clinoform structure presumably of the Middle-Upper Cambrian is defined in the Siberian Platform north-western margin based on data of southern end of the Dikson-Khantaiskoye Lake seismic profile. The Siberian Platform clinoform Cambrian sections are concentrated in transition areas from non-compensating type to reef barrier one. Thus, carboniferous Lower-Middle Cambrian deposits are distributed in the form of a strip stretching in the northwestern direction from the south Pri-Anabar to the western Siberian Platform. Spatial combination of vast focus of hydrocarbon generation and reef barrier allows authors to consider the latter as the highest priority target of petroleum exploration in the northern Siberian Platform in indicated deposits. The most promising are clastic carbonate formations on the reef structures slopes, reef-front calcareous-dolomitic sandstones. Regional fluid trap is the Middle-Upper Cambrian complex of argillaceous-carbonate rocks. It is proposed to conduct seismic investigations using denser traverse network aimed at localization of exploratory prospects and site selection for parametric drilling on the eastern edge of the Kureika syneclise.

Key words: seismic data, wave field, Lower-Middle Cambrian section types, facies regions, Kuonamka Formation, reef barrier, Siberian platform, hydrocarbon prospects.

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