Purpose. The work is aimed at studying the faulting dynamics and the types of disjunctive structural traps for ore solutions under alternating movements in the zones of shear, transpression and transtension. Methods. Physical modeling was performed in the Laboratory of Tectonophysics, Institute of the Earth's Crust SB RAS on the Fault Installation, which allowed to set up both the direction and two speeds of stamp (plate) movement (10^-4 and 10^-5 m/s). The studies were carried out on the basis of the experiments of physical modeling with the use of an equivalent material in the form of an aqueous suspension of montmorilonite clay (viscosity of 10⁶-10⁷ PA∙s). Each experiment included two stages. Stage I reproduced the conditions that correspond to shear, shear with tension (transtension) or shear with compression (transpression). Stage II included the simulation of structure forming under reverse movement of experimental installation stamps, i.e. under alternating shear of transtension or transpression. Results. The parageneses of fractures with the emphasis on extensional structures that can be favorable for kimberlite body location have been studied in the series of 8 experiments. The formation patterns of disjunctives are examined in terms of shear zone paragenesis formation in the models of known discontinuities. The extensional structures favorable for ore deposition are more characteristic of the experiments performed at slow speed. Another factor affecting the formation of the internal structure of fault zones is the vector of relative movement of stamps (plates), on which the dynamic conditions of the first and second stages depend. Consideration is also given to the combinations of right- and left-lateral shearing, transtension-transpression, and transpression-transtension. Conclusion. The physical modeling experiments have shown that the deformation rate has a significant influence on structure formation. In case of alternating movements in fault zones the deformation rate is the factor that affects the width of the fault zone and the distance between the fault systems as well as the specific set of elements in structural paragenesis. Extensional structure of the different types characterized by the highest tension amplitudes occur near the major joints of disjunction, where the dilatancy is the highest. The dilatancy is manifested most clearly in the fault zones which are formed in transpression conditions at the stage I and under transtension conditions at the stage II. The largest disjunctive structural traps associated with е-, R- and Y-fractures are observed in such fault zones.

Purpose. The purpose of the paper is evaluation and analysis of the amplitude-frequency patterns of background microseisms (local ambient noises) and their possible seasonal variations in the territory of the Baikal seismic zone. Methods. The method of spectral relations of the vertical and horizontal components of the microseism (H/V-ratio) or Nakamura method is used. The continuous seismic recording data obtained by 23 short-period seismic stations of the Baikal Branch of the Federal Research Centre “Single Unified Geophysical Survey of the Russian Academy of Science” located in the Baikal seismic zone are used as an input material for the analysis. Only long segments of seismic records with the duration of at least 1 hour have been selected for the analysis in order to exclude possible random errors related to human-made noises, earthquakes, industrial explosions, etc. Results. The obtained curves of H/V-ratios and their seasonal variations characterize the amplitude-frequency patterns of local ambient noises in the frequency range from 0.5 to 10.0 or 20.0 Hz depending on the type of the recording equipment used. Conclusions. The obtained H/V-ratio curves can be conditionally divided into two groups: stable and featuring significant seasonal variations. The first group includes the stations with stable amplitude-frequency characteristics of the microseismic signal, which do not depend on the season. The second group includes the stations for which the H/V-ratio curves demonstrating significant seasonal variations have been obtained. Having compared the position of the seismic stations and the obtained H/V-ratio curves, the authors identified the dependence of the amplitude-frequency characteristics of the microseismic signal on their local conditions in the station setup area (at the outcrops of bedrock, in the zone of large active faults or in the rift depressions with a thick sedimentary cover).

The Purpose of the paper is to carry out a complex analysis of fracturing and compare the results of two fundamentally different reconstruction methods of tectonic stress fields on the basis of geological and structural data of the Tazheran site in Pribaikalie. Methods. The study employs a new approach to the paragenetic analysis of statistical measurements of «mute» fracturing, which allows to restore the stressed state of a local rock volume and determine its belonging to the fault zone of a certain morphogenetic type and orientation. The second reconstruction method of stress fields is a kinematic method based on the analysis of fracture displacement vectors. Results. The analysis of 22 mass measurements of fracture attitude (100 joints each) and 158 measurements of slickensides at 16 observation points has been carried out. We have obtained 70 solutions of the paragenetic method and 26 solutions of the kinematic method on local stress fields. Fracture parageneses were formed in the fields of compression, shear and strike-slip in approximately equal amounts. The traces of displacements are more developed in strike-slip fields. A comparison of results for each observation point has showed that most of kinematic solutions (21 of 26) have a paragenetic solution similar in type and orientation for the stress field of the first or second order. Conclusions. The reconstruction results of local stress fields by two methods are comparable and in general complement and partially confirm each other. The identical stress fields restored by different methods are presumably referred to one stage. The other mainly paragenetic solutions indicate stress fields in the early development stages of small fault zones within the site. A complex use of paragenetic and kinematic methods is recommended.

Purpose. The purpose of the work is to analyze the oil and gas content of the Siberian platform based on the study of global historical-genetic and geological aspects of hydrocarbon ontogenesis. Methods. The methods used include interpretation of geodynamic, structural-tectonic and lithofacial factors of the oil and gas potential of the Siberian platform through studying the features of hydrocarbon deposits on its territory. The following most important global conditions for oil and gas potential of the south of the Siberian platform are analyzed: 1) huge areas of Riphean-Vendian-Cambrian sediment distribution in the vast Riphean sedimentary basins of the Siberian platform; 2) lithofacial composition of rocks, availability of thick layers of rock salt, presence of numerous archaeocyathid algae bioherms in the Riphean-Vendian-Cambrian deposits as a convincing proof of favorable paleogeographic and paleoclimatic conditions of these periods, which were determined by the position of the earth in the zone of low latitudes; 3) duration of the Riphean stage of Siberian platform development (more than 1 billion years) characterized by the formation of types of structural zones and numerous rifts different in kinematics and scales; 4) presence of incratonal and pericratonal rifts as the most permeable lithospheric structures on the territory of the Siberian Platform. They create optimal conditions for the transit of deep fluid flows, which are critical for naftidogenesis processes; 5) availability of different age genetic types of natural reservoirs with a set of lithogeodynamic complexes formed at different geotectonic stages of rock-sedimentary basin development. Results. Having summarized the geological and geophysical information of the recent years, the author analyzes global geological and historical-genetic backgrounds of the petroleum potential of the Siberian Platform that create the most favorable conditions for hydrocarbon ontogenesis. Conclusions. The listed backgrounds are confirmed by the proven and promising oil and gas potential of the Riphean - Vendian - Cambrian sediments of the south of the Siberian Platform, to which numerous hydrocarbon deposits are confined.

The purpose of the paper is to justify the assembly of drilling equipment and the diagram of wellhead surface piping when drilling wells with bottom hole cleaning by a self-destructing foam in a closed-loop circulation cycle. Methods. The schemes of equipment piping for foam drilling of wells have been developed on the basis of the performed review and analysis of the technology and technical means. The equipment under consideration is applicable for various depth wells, methods of foam production for exploration drilling. The development results have been tested in the drilling of production wells. Results. The optimal regulation of airflow, foaming agent consumption and required pressure of foam injection is provided. Special booster compressors, which are mounted on the hydraulic part of the pumps of 11GRI or NB-4 type have been developed. They operate as compressor second stage and allow to neutralize the adverse effect of the hazardous space when working on a compressible environment. Preparation of foam in special surface foam generators allows to produce the high quality foam and ensure more rational use of the foaming mud. Justification is given to the possibility to control foam expansion ratio under its preliminary production by the selection of the optimal ratio of airflow and foaming agent consumption or variation of design parameters of a foam generator. Conclusions. The use of the proposed technological schemes of equipment piping (a low pressure compressor and a drilling pump with mounted aerators, compression chambers, boosters, as well as high pressure compressors for general flow foaming) for specific geological and technical conditions of foam drilling allows to achieve an optimal mode of trouble-free penetration of complicated horizons with the controlled hydrostatic pressure.

Purpose. The research is aimed at studying the geological structure of the Kovykta gas condensate field in the Irkutsk region, identifying and outlining of the zones of heterogeneous structure of the productive deposits of the Parfenovsky horizon of the Chorsky formation of the Vendian period as well as the assessment of the need for a revi-sion of the reservoir petrophysical model presented in 2013 when the hydrocarbon reserves of the Parfenovsky horizon of the Kovykta gas condensate field were calculated. Methods. The analysis of calculated parameters distribution (ef-fective thickness, open porosity coefficient) and field characteristics (delivery) of the Parfenovsky horizon reservoirs is performed by the field area and by the section. The differential distributions of effective thicknesses and reservoir po-rosity are compared before and after the division of the Kovykta gas condensate field into the zones with a different type of the Parfenovsky horizon section. Results. The data on the structural features of the Parfenovsky horizon reservoir rocks of the Kovykta gas condensate field are provided. Three types of the Parfenovsky horizon section have been identified. The wells of the Kovykta gas condensate field have been ranked by the type of the Parfenovsky horizon sec-tion and its test results in the open borehole and/or in the drill string. The directions of further study of the structural fea-tures of the Parfenovsky horizon reservoirs have been determined. Conclusions. The Parfenovsky horizon features the presence of reservoirs with improved and degraded porosity and permeability. The presence of the reservoirs different in properties and composition in the Parfenovsky horizon deposits has revealed the need for the revision of the petro-physical model and the methodic base of the integrated interpretation of well geophysical research data presented by the recalculation of hydrocarbon reserves of the Kovykta gas condensate field in 2013.

The Purpose of the paper is to study the possibilities of regression and variance analyses under quantitative interpretation of gravitational anomalies. Methods. On example of the Ulanbaatar and Nalaikh intermountain depressions (Mongolia) the application possibilities of the principal component method and the pseudo-inverse algorithm under the transformation and inversion of gravitational fields are considered. Results. The quantitative characteristics of the thickness of loose deposits of the structures under investigation are obtained through regression and variance analyses. The maximum thickness of the deposits of the Ulanbaatar depression is 100-200 m whereas the Nalaikh depression is 600 m. The obtained estimates are confirmed by the results of investigated depression gravitational field inversion by other methods. Conclusions. The transformation and inversion results of the gravitational field of sedimentary deposits of low thickness (100-200 m) when replacing infinite length rectangular prisms by the parallelepipeds limited along the strike vary insignificantly and remain within the initial limits (while maintaining the magnitude of the lack of density). The depression filled with the sediments of great thickness features a significant increase in this characteristic (from 600 m to 900 m) while maintaining the lack of sediment density. Such variations in the sedimentary thickness of the studied objects can be explained by the magnitude of the visibility angle of individual geometric bodies approximating precipitation lenses. It is found that the application of the method of principal components of the variance analysis in the identification of the regional and local (residual) components of the gravitational field and the inversion of the anomalous gravity field using a pseudo-inverse algorithm of the regression research method are quite possible and effective.

The Purpose of the paper is to prove the need for accounting the environment fractality under countouring of ore zones, bodies and geometrization of mineral deposits as well as to find the conditions of compatibility of the deterministic theory of the stratified geochemical field of the professor P. K. Sobolevsky in the conditions of fractal environment. Methods. The study uses the review of literature and researches in the field of synergetics and fractal geometry as well as mathematical processing and analysis of fractal geological systems. Results. The self-organizing dynamic system features the domination of nonlinear relationships, while the location of each fractal in the conditions of "the determined chaos" is random and unpredictable. The existing deterministic idea of a deposit as a geochemical field (P. K. Sobolevsky) meeting the condition of finitude, unambiguity, continuity, smoothness and having a stratified structure is in a conflict with the distribution discreteness of useful components, ambiguity of data (for a specific point of space). The contradiction can be eliminated if a geochemical field is considered in some volume rather than in a point and the content of a useful component or other indicators are referred to the center of this volume. The method of isolines is introduced in practically all areas of scientific knowledge. It is evident, informative enough and it is impossible to refuse it. Conclusions. The fractal analysis should be added to the methodical basis of geometrization with a system approach in scientific researches as its element since it is an integral part of synergetrics today. It will allow a more rational justification and selection of technological decisions for geological object development. When the theory of geochemical field is adapted to a certain volume of subsoil rather than to a point we obtain a random component. Therefore, it is necessary to operate random spatial fields where probabilistic methods, the theory of stochastic functions and geostatistics predominate.

The article is dedicated to the memory of the outstanding Siberian geomorphologist, Doctor of Geological and Mineralogical Sciences, Professor Gennady Feodosievich Ufimtsev who was a recognized expert in the field of modern tectonics, geomorphology and physical geography. He was distinguished by the width of scientific interests, encyclopedic knowledge, enthusiasm and passion in work, which ensured his success in science. He is the author and co-author of more than 700 scientific papers. He produced numerous monographic studies on the neotectonics of the Far East, the Baikal Rift Zone, mountain belts of the continents, morphotectonics of Eurasia, and the structure of the Earth relief. G.F. Ufimtsev is one of the pioneers of a new scientific direction - aesthetic geomorphology, which deals with the complex multi-aspect relationships between a man and the earth's surface relief including the effect of relief on the elements of ethnic culture, national character and sustainable development of society. A special place in the activity of the scientist belonged to the cataloging and description of geomorphological monuments declared the UNESCO World Heritage sites. G.F. Ufimtsev was the head of the Russian Association of Geomorphologists, a member of the Russian Geographical Society and a national delegate to the International Geomorphological Association. For outstanding results in the study of mountainous terrain and popularization activities G. F. Ufimtsev was awarded the gold medal named after N.M. Przhevalsky, which has been one of the most honorable awards of the Russian Geographical Society since its introduction in 1891.