Дніпровсько-Донецька западина

The second part of the article studies the tectonic conditions and natural mechanisms of tectonic inversion of the Dnieper-Donets Basin and the Western Donets Graben. Method. The research uses the original method of reconstruction of fields of tectonic stresses and deformations. It also makes tectonophysical analysis of geostructures was used. The analytical base of the research consisted of the latest materials of geo-mapping, numerical modeling of deformations of the southern edge of the Eastern European platform and comparison of model and reconstructed stress fields. Results.

Aim. Geodynamic interpretation of previously obtained 3D density and magnetic modeling results, and data on consolidated crust fault tectonics of the Dnieper part of Dnieper-Donets basin (DDB) in the light of its formation mechanism.

On the base of computer modeling with calculation of the rock radioactivity was analyzed the behaviour of the heat fields of the central part of DDH in the beginning and in the end of the rifting stage. It was showed, that temperature conditions necessary for activity the process of eclogite metamorphism in the lower layers of the crust took place during all this stage. Another hand, for activizations of process of progressive stage of granulate metamorphism in the lower granite layers it was necessary the process of long heating of the crust during about 10 ml. years.

Using facts of rifting origin and development of Dneprovsko-Donetsky hollow (DDH), it was carried out  computer modeling of the phone temperature fields of the earth crust in the cross sections of Chernigov, Poltava and Harkov megablocks of DDH. It was showed, that visible distinctions of the temperature fields were fixed in the lower and middle parts of the crust, in the upper part, starting from 10 km layer, temperature fields were differed very little.

Results of field geophysical investigations and data of litological-petrophysical studies of core samples have been analyzed. A complex of petrophysical and geophysical indicators of rocks of lithological traps in the Lower Carboniferous deposits of the Dnieper-Donets Depression has been developed. It was concluded that the best reservoir rock properties are characteristic for the channel and bar sand bodies, represented with anisomerous quartz sandstones with carbonated-clayed and quartz-clayed-carbonated cement.

In the paper, a method and results of integral modelling of velocity distribution of seismic waves are presented. A method for processing and interpretation of vertical seismic profiling data to estimate average, vertical and layer velocities is suggested. Based on these data, an integral model of velocity distribution for a most promising part of Dnieper-Donets basin was built. Results of the work can be used to build 3D depth models of oil and gas deposits, to refine time-depth relationships in the existing models.

The current work performs the comparison of distribution of geothermal gradient depending on the display of hydrogeological inversion and location of hydrocarbon deposits. On the example of Yarmolintsivske and Machuske fields is shown that the increase of the gradient takes place at the intersection of the roof of the deposit. The average geothermal gradient over deposit is set to 19-20 °C/km in both cases.

The aim of the study is to determine the volume of distribution parameters and petrophysical properties of rocks in the unconventional hydrocarbon fields are based 3D-modeling. Used Methodology is related to the analysis of geological and technological parameters and conduct three-dimensional modeling.