The relevance of the research is caused by insufficient knowledge on the Paleozoic oil and gas deposits of Western Siberia and the Altai-Sayan folded region associated with it, although new oil and gas condensate fields have recently been discovered in this territory. Paleozoic deposits are highly promising objects for discovery of hydrocarbon deposits. The results of paleogeographic and lithological-geochemical studies of the region under study can significantly affect the reconstruction of paleoenvironments favorable for generation and accumulation of hydrocarbons, as well as assessment of the prospects for oil and gas potential of Paleozoic sediments and identification of unconventional reservoirs. Objects: carbonate deposits of the Zhivetian stage of the Middle Devonian, outcropping in the quarries Kamen and Podlomsk (Tomsk region), Lebedyansky quarry (Kemerovo region), in the areas of Lake Fyrkal and Oshkol, as well as west of the lake Tus (Northern Khakassia). Purpose: paleogeographic reconstruction of sedimentation environments favorable for oil and gas accumulation, as well as identification and assessment of the prospects for oil and gas potential of Paleozoic sediments in the rocks of the Paleozoic basement. Methods: lithological-petrographic, paleontological, paleogeographic, lithogeochemical (X-ray spectral, scanning electron microscopy, luminescence microscopic, inductively coupled plasma mass spectrometry (ICP-MS)). Results. The authors were the first to establish signs of oil and gas content of the Middle Devonian deposits in the Tomsk region (Kamen and Podlomsky quarries), in the Kemerovo region (Lebedyansky quarry), in Northern Khakassia (areas of Lake Fyrkal and Oshkol, as well as west of Lake Tus). As a result of paleontological and geochemical studies, the features of the paleoenvironment of sedimentation, favorable for accumulation of OM, burial and generation of hydrocarbons, have been revealed. Among the studied sediments, the petrotypes: boundstone, rudstone, floutstone, packstone, wakstone and mudstone, which underwent intensive postsedimentary transformations, significantly influenced their reservoir properties, were identified. Luminescence microscopic studies made it possible to establish the facts of intensive fluid migration in the studied areas and to identify potential reservoirs. It was found that the largest amount of bitumoids is recorded in reef boundstone limestones. This petrotype has a high reservoir potential, because the corals composing it have good qualities for this – cavernousness and biowasiness.