Correlation between the content and composition of organic matter with the lithological types of rocks in the Bazhenov formation

Extensive lithological and geochemical studies of the core of the deposits of the Bazhenov formation have been performed. Some aspects of the laboratory core research method based on the study of rock samples before and after exposure to organic solvents are considered. The depositional environment of the Bazhenov formation, the properties and sediments specifics, similarities and differences of the main deposits of the formation are described; the reasons for their differences are indicated. Characteristics of source rocks and reservoirs are given. Special attention is paid to the content of hydrocarbons in different types of rocks. The factors affecting the formation of the reservoirs in Bazhenov formations as well as the properties of various types of reservoirs and the patterns of their distribution in the vertical section and on the area are described.
Materials and methods
Comprehensive core analysis and comprehensive core data interpretation.
Results
The dependence of the content and composition of organic matter on the lithologic types of rocks of the Bazhenov formation was established.
Conclusions
The content of organic carbon reaches 5-25% in the source rocks. The share of "free oil" accounts for 5-15%, hydrocarbons and heteroatomic compounds of the oil sequence, extracted during hot extraction, accounts for 20-50%, products of kerogen cracking accounts for 35-75%. In the secondarily converted radiolarit, the content of organic carbon does not exceed 5%, most of it is represented by "free oil" and oil-like components. At the existing level of uncertainty of the properties and structure of the Bazhenov formation, it is necessary to conduct detailed integrated laboratory (lithological, petrophysical, geochemical) core studies to solve any production tasks, calculate reserves and plan the field development.