Gas-dynamic characteristics of rocks of the Udachnaya formation (Є1-2) within the mine field of the Udachnaya pipe (Republic of Sakha (Yakutia))

Abstract

Introduction: The Udachnaya kimberlite pipe requires a comprehensive study of its mining and geological conditions to make underground mining safe. The presence of rock intervals saturated with hydrocarbon gases, natural brines, and caustobiolites requires systematisation of fluid segregation intervals as well as an assessment of the gas-dynamic component. The involvement of production blocks at the level of occurrence of the Udachnaya formation will allow providing the production capacity of the Udachninsky GOK with raw materials for the following 30 years.

Methodology: The study of the main gas-dynamic parameters of the deep horizons of the field was carried out by drilling test wells, for which interval determination of reservoir gas flow rates was carried out, using packer installations and integrated research equipment (CIE). Gas samples were also taken to determine their chemical composition and gas logging was carried out.

Results and discussion: At the levels of the Udachnaya formation, 8 reservoirs were identified in the upper subformation, 7 reservoirs were identified in the lower subformation, which were grouped into 5 zones, differing in thickness, type of fluid saturation and reservoir pressures.

Conclusion: The presence of gas-saturated reservoirs in the section of the Udachnaya formation, providing a significant influx of formation gases to the system of underground mine workings, estimated from the results of studies at a value of ~ 1‒2 thousand m³/day, allows indicating the need for early degassing using those already developed technologies at the Udachny mine.