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The South Baikal earthquake of 25 February, 1999 had the main shock in the south-western part of Lake Baikal with the normal-slip focus at the intersection of the Obruchev (Primorsky) and Angara faults. This was the strongest shock (M_PSP = 6.0) in the southern Baikal region over the last 40 years after the M_LH = 6.8 Central Baikal earthquake of 1959. The intensity attained 7-8 in the epicentre, 6-7 in villages 15 to 30 km away on the north-western and south-eastern sides of Baikal, and 4-6 in neighbouring cities of Irkutsk, Angarsk, and Ulan-Ude. The main shock was followed by a long series of aftershocks with different focal mechanisms. This event occurred in a region for which pending seismic risk in the nearest 15 years was predicted in 1994.

The relationship between oil reserves and annual oil production is considered. The correlations between the Russian and American resource classes are discussed in the context of the difference in this relationship in Russia and USA.
The notions of quality of explored reserves (reserve concentration, well production rate, and recovery of initial reserves) and inferred resources (concentration of the initial total resources and degree of their exploration) are considered. Depauperation of residual resources of various classes during their development is inferred.
The main results of prediction of petroleum production in Russia in the 21st century are reported. The peak of oil production is expected to be in 2020, and of gas production, in 2030. A decrease in oil production to 2.0-1.8 10⁸ tons and in gas production to 3.5–10¹¹ m³) is expected by 2100.

main petroleum-bearing belts are confined to the passive margins of continents – recent and ancient. The recent margins form three global belts which can be considered subtypes differing in time and rifting-spreading stages: Indooceanic-Atlantic, Circum-Arctic, and Mediterranean-Persian.
Sedimentary basins of the three subtypes are characterized by a high rate of sedimentation, up to 5-10 cm/ka, but differ in recent thermal regime. One subtype has an increased thermal regime with a depth of 100 ^oC isotherm of 2-2.5 km in separate basins. The other two subtypes are characterized by a different thermal regime, with 100 ^oC isotherms established at depths of 5-7.5 km.
In the case of ancient passive margins, large fields are connected with rift massifs. The post-rifting stage of these belts can be finished by thrusting emerged near orogen and accompanied by formation of molasse foredeeps and multilayer nappe structures. The second type of petroleum belts is confined to active margins, mainly to the Circum-Pacific belt and Western Mediterranean region. Associated with different-age zones of subduction, the basins of the Caspian-Black Sea region can be distinguished as a specific subtype. Subsidence at the last stage is accompanied by an avalanche rate of sedimentation, up to 30 cm/ka. The increased thermal regime (except for the basins of the Caspian-Black Sea subtype) with 100 ^oC isotherms at depths of 1.5 to 2.5 km contributed to quick generation of organic matter and the most complete realization of petroleum potential.
The third is intraplatformal type of petroleum-bearing belts associated with continental platforms. It is subdivided into subtypes - rifting and epirifting. In the first case, thermal regime is rather high, with the depth of 100 ^oC isotherm ranging from 1.5 to 0.5 km; in the second case it is low with the depth of 100 ^oC isotherm of about 5 km.
The forth type includes basins of intermontane troughs of orogens. The basins of this type are rather small but with thick sediments and high sedimentation rate of 3-6 cm/ka at the Cenozoic stage. The thermal regime is characterized by the depth of 100 ^oC isotherm of to 5 km in intermontane basins of young orogens and to 1.5-2.5 km in rejuvenated orogens.
The sedimentary fill of active-margin basins and intraplatformal and intermontane troughs of young orogens is subject to tangential stress caused by collision of lithospheric plates and is characterized, especially along the periphery, by fold-thrust strains, often with stripping of sedimentary units off the basement or along the plastic horizons in the cover.
To estimate petroleum potential in each type of basins, it is necessary to take into account some endogenic factors: thermal regime, deep-level fluids, lateral stress, rate of sedimentation, etc.

The problem of forecast of the largest (giant) oil and gas deposits arises not from insufficient empirical knowledge (most recoverable HC resources of the world have been prospected) but from the necessity of its generalization and theoretical justification. Transition from empirical to theoretical level of knowledge requires a deeper integration of oil geology as a special study into the general structure of natural sciences, which requires formalization of a special knowledge in accordance with general principles and laws of the natural science. Inductive analysis traditionally used in oil geology in the context of historical and genetic approach must be complemented with deductive analysis based on static approach. Particular methodological forms of the latter approach are techniques of mathematical simulation, based on regularities in distribution of HC resources of oil and gas basins (OGB) among deposits of various sizing classes, and techniques of analogous structurization, based on regularities of distribution of giant deposits in the planetary system of OGB.

Astronomical and geochronological substantiation of galactic years and the orbital geochronological scale are considered. Climatic seasons of Phanerozoic galactic years are recognized. The dependence of various geochemical and biological phenomena and events, as well as formation of mineral deposits, on the position of the Sun in its galactic orbit and the related galactic climatic seasons is discussed.

The paper considers the criteria of influence of trappean magmatism on the petroleum potential of sedimentary basins. Particular emphasis is placed on the thermal effect of intrusive bodies on organic matter and hydrocarbons. The principles of classification of sedimentary basins are presented based on the degree of maturity by the time of the most intense stage of trap intrusion. The foundations of the technique of calculation of the predicted hydrocarbon resources are given for the basins of different types.

Studies of the traces of Riphean and Phanerozoic earthquakes in the Caucasus, West Siberian Plate, and Siberian Platform, as well as their comparison with the geological evidence of modern earthquakes, show that they may have played a role in the formation of oil and gas traps and accumulation zones. The seismogenic zones of oil and gas accumulation, which are of three main varieties (autochthonous, allochthonous, or transit), are considered in terms of their formation mechanisms and prediction. For such zones in the Caucasian foredeep, West Siberian Plate, and Siberian Platform, probable stratigraphic levels, locations, and types are outlined and example predictions are suggested.

In many regions of the world, including West Siberia, deposits of hydrocarbons in hydrate state are considered to be petroliferous formations. As to methods of search, prospecting, and exploitation of this kind deposits, however, the state-of-the-art is not satisfactory.
In Russia, the problem of existence of gas hydrate deposits is usually discussed in the context of hydrate saturation of the Cenomanian gas pool at the Messoyakha deposit. One more producing horizon has been recognized in the north of West Siberia, which is related to the Gazsalin Member of the Kuznetsov Formation of Turonian-Coniacian age, lying above the Cenomanian deposits and having more favorable PT-conditions for hydrate formation.
Analysis of specific features of geologic structure, temperature regime of the section, gas composition, mineralization of formation waters, logging data, seismic prospecting materials, and sampling suggests that gas hydrates can exist in the Gazsalin Member of the East Messoyakha deposit.
One of the possible directions of further study of genesis of natural gas hydrates and estimation of the effect of gas hydrate processes on the structure of gas deposits and gas resources is study of the hydrocarbons accumulated in the Gazsalin Member of the East Messoyakha deposit with sampling of core by a sealed thermostatically controlled corer.

The paper deals with the problem of bacterial oxidation (biodegradation) of crude oil hydrocarbons. The review of the literature on natural biodegraded oils and laboratory experiments suggest that the normal and branched alkanes are susceptible to microbiological degradation, as well as polycyclic saturated biomarker hydrocarbons (steranes, hopanes, and cheilanthanes). The homologous series of demethylated hopanes are assumed to be of different genesis: 28-norhopanes have the precursors in membranes of prokaryotes, i. e., they are "primary" biomarkers, while 25-norhopanes result from bacterial oxidation of regular hopanes in oil pools. Homohopanes close to "biological" structures (22R) are the first to be assimilated by bacteria. At the final stages of biodegradation, demethylation of cheilanthanes occurs at C-10. All this allows construction of the stage scale of hydrocarbon biodegradation.