Zelenko Y. Prediction of oil and gas generation potential of the Paleozoic sedimentary complex of the south-eastern part of the DDB according to geological and geophysical data for prospecting for hydrocarbons

The theses are for the Candidate Degree in Geological Sciences. Specialty 04.00.22 – Geophysics. – Taras Shevchenko National University of Kyiv, Ministry of Education and Science of Ukraine, Kyiv, 2018. Based on mathematical processing of geological data the coefficient of reflectivity of vitrinite predicted maps are drawn, which confirm the existence of oil and gas generating strata at a depth of 5 km south-east of the Dnieper-Donetsk depression. An analysis of the created petrophysical coupling patterns of the properties of clay-silty rock with a high content of organic matter and characteristics of geophysical fields revealed the reflection of anomalous characteristics of the kerogen in geophysical fields and the ability to predict promising areas for the detection of non-conventional gas deposits in low permeable clay-aleurite rocks. The use of geophysical methods for determining the content of organic matter by the algorithm of comparing two geophysical methods of determining the difference between geophysical curves is based on the application of supporting layers. In the dissertation the method of determining the interval of the reference layer is proposed and based on comparison of the measured neutron logging curve with calculated synthetic curves in clay layers under two conditions: a) absence of organic matter and b) enriched layers with organic residues. In this dissertation the connection between the parameters characterizing the organic matter in the rock was studied and the dependence between the reflectance of the vitrinite and the value of the hydrogen index (which is characterized by the inverse exponential function) is constructed. Using the dependence of the reflectivity of vitrinite on the thermal maturity of the kerogen, a method for determining the thermal maturity of organic matter in the wells according to the well logging evaluation data is proposed. In this dissertation the control of the reliability of the solution of geological and geophysical problems an algorithm is proposed, based on the use of communication patterns a) clay rocks of only dispersed composition, b) clay rocks enriched with organic matter - between the magnitude of natural radioactivity and the intensity of the secondary gamma field (equivalent to hydrogen content). The relative parameter describing the ratio of the value of the hydrogen content of the rock to the unit fraction of the disperse fraction (clay) is proposed to increase the reliability of the evaluation of the content of organic matter in clay-aleurite rocks. The block geological structure of the foundation significantly influences the understanding of the processes of formation and availability of different types of traps, different from the classical, in which significant deposits of hydrocarbons are concentrated. The results of experimental core research and data obtained in the process of deep drilling, considering the geophysical parameters, confirmed the above conclusions. In the course of scientific research, it was established that the dissipation zones were in fact both zones for the generation of hydrocarbons and their accumulation in tanks filled 20 with sealed rocks of a crack type with a high content of kerogen. The conducted studies of the distribution of parameters of electric, radioactive and neutron fields indicate the complex nature of the connection of the lithofacial conditions and the geophysical properties of the clay-aleurite rocks, enriched with organic matter. The analysis of the pyrolytic characteristics obtained during the processing of data on the Rock - Eval method of coal deposits in the marginal and central parts of the DDB showed that the deeply submerged carbon deposits have basically gas generation potential. On the basis of the analysis of the relationships between the properties of the natural radioactive field (by gamma-logging method) and the intensity of the formation of thermal neutrons (by the neutron-neutron logging method), on the example of well number 1-Artemivsk, it was established that, in general, the decrease of gamma field values leads to increase neutron logging.