Geoinformatika 2016; 3(59) : 20-24  (in Ukrainian)

SPATIAL DISTRIBUTION OF KEROGEN TYPES BASED ON DATA PROCESSING OF SAMPLES BY PIROLYSIS METHOD WITHIN THE DNIEPER-DONETSK DEPRESSION

Yu.М. Zelenko, O.V. Dziuba,O.M. Karpenko

Taras Shevchenko National University of Kyiv, Institute of Geology, 90 Vasylkovska Str., Kyiv 03022, Ukraine,
e-mail: zelenko.yuri@gmail.com, geoinformatic@ukr.net, alexbrig@inbox.ru

The purpose of the paper is to investigate source rocks and explore the thermal maturity of organic matter-rich coal strata between the Dnieper-Donets depression and Donetsk folded structure with the view to assess their gas generation potential and prospects of gas content assessment.
Design/methodology/approach. We proposed a pirolytic method to study spatial distribution of kerogen types. We analyzed of 60 samples of kerogen based on statistical data processing of pyrolytic parameters (pH and temperature index maximum output of hydrocarbons in the cracking kerogen). The paper studies kerogen types and the nature of saturation of productives trata by the method of benchmarking and comparisons. To assess the degree of katagenesis transformation of organic matter, we used data vitrinite reflectivity (R⁰, %).
Findings. The results of the data processing were obtained by pyrolysis “Rock-Eval” rock samples from wells of different parts of the Dnieper-Donets basin. The allowed us to evaluate the spatial distribution of different kerogen types and determine the nature of the maturity of organic matter within the individual Straton disclosed wells. The studied kerogen types of individual structures coincide with the lateral distribution of hydrocarbons. Pyrolytic parameters used to construct the combined diagrams and their analysis provides information about genetic and katagenetic characteristics of kerogen. These diagrams include the dependence of a hydrogen index (HI) on the temperature maximum output of hydrocarbons from organic matter (Tmax). This allows us to select fields of various types and degrees of katagenesis transformation of organic matter. We developed a semi-automated system for calculating the content of “free” hydrocarbons in rocks.
Practical value/implications. The authors suggest methods of data processing to createan evolutionary chart of organic matter. We confirmed different kinds of mature organic matter from the existing oil fields and the potential gas reserves of the unconventional type within the studied structures. The investigation of the distribution of organic matter content makes it possible to identify the most favourable times for the gas generation section within the studied areas. These intervals are taken as favourable for localizingthe unconventional gas type.

Keywords: Dnieper-Donetsk depression, type of kerogen, organic matter, hydrogen index, pyrolysis method “Rock-Eval”, evolutionary chart.

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