The efficiency of the regional geophysical complex (seismic, gravity and magnetic surveys) in the Kurshskaya depression of the Baltic syneclise

(Gololobov Yu.N. Druzhinina E.A. Suprunenko O.I. )

The main results of the geophysical complex (seismic, gravity and magnetic surveys) in the scale 1:200 000 during 2015-2017 years on the Kurshsky Bay' shelf of the Baltic Sea are discussed. New technological method was used for the reworking of the potential fields data and the modelling of geological slices of the basement and sedimentary cover, namely the classification of the anomalies with different spectral parameters (A.I. Atakov' algoritm). Obtained new data assume the changes of existed longstanding opinions about geological structure of the basement and sedimentary cover and oil and gas prospects of the Kurshsky Bay.......

  • 2018  № 3, pp. 17-23

Nature of harmonics in the vibroseis method and the possibility of their utilization to broaden the signal frequency band

(Denisov M.S. Shneerson M.B. )

Generation of elastic waves in the Vibroseis method is accompanied by the appearance of harmonics, i.e. the waves with multiple frequencies relative to the fundamental frequencies. Traditionally harmonics were regarded as noise and essential effort was devoted to their removal. In our opinion, harmonics might be utilized for seismic signal frequency band broadening. A parametric model of a complex vibroseismic signal is introduced and an optimizational procedure for spectrum broadening is proposed.......

  • 2018  № 3, pp. 24-27

Regarding the relationship between bulk modulus of a fractured rock mass and actual stress state

(Dubinya N.V. Fokin I.V. Rusina O.A. )

The article is devoted to the experimental observation of naturally fractured rock samples' deformation while applied to triaxial loading. Multi-stage loading tests are carried out for a number of rock samples. The concept of critically stressed fractures is used describing the analyzed process. Each stress state is considered using Mohr diagram and characterized by calculated parameter which stands for the relative amount of fractures along which the sliding process is possible. These fractures are referred to as “critically stressed” and the described parameter is fraction of critically stressed fractures. Series of tests were performed for samples of two collections (granite and carbonate samples). For both collections it is shown that the relationship between specifically introduced bulk elastic modulus and fraction of critically stressed fractures shows signs of self-similar behavior. The bulk modulus vs. fraction of critically stressed fractures curves obtained for different values of radial stress overlap. That means that fraction of critically stressed fractures is a self similar parameter which increases the value of information obtained from multi-stage tests and contributes to the actual problem of stress state estimation from effective elastic moduli of the medium.......

  • 2018  № 3, pp. 28-32

Quantitative prediction of reservoir properties using 3D seismic and well data based on machine learning algorithms

(Priezzhev I.I. Egorov S.V. Gladkov E.A. )

This article describes the use of machine learning algorithms for the purposes of the forecast reservoir properties from seismic and wells data. Described the theoretical basement of machine learning algorithms and neural network. Reviewed the design concept of neural net. The result of application is demonstrated on the conditions of the Jurassic formation of Western Siberia.......

  • 2018  № 3, pp. 33-38

Optimization of seismic exploration for salt-dome case based on 3d full-wave computer simulation

(Kaplan S.A. Vedenyapin O.A. Levchenko V.D. Lebedev E.B. Levchenko T.V. Rok V.E. Perepelkina A.Yu. )

The information content of regional 2D seismic studies for subsalt oil and gas deposits' exploration in the Caspian Basin and improving the methodology of field observations and processing of the seismograms the possibilities of study methods of regional seismic explorations in salt-dome tectonics is enhanced on the basis of computer full-wave 3D simulation and processing of the theoretical seismograms. Combined, relatively thick-layer digital models with the inclusion of thin layer rock packages containing reservoirs were synthesized on the basis of the available geological and geophysical data to calculate the full seismic wave fields for various 2D and 3D systems of observation. Recommendations are formulated on acquisition geometry and seismic data processing enhancing the ability of detection, localization and estimation of properties of oil and gas bearing objects in the subsalt sediments.......

  • 2018  № 3, pp. 39-46