Regional and Local Systems of Methane Gas Distribution in the Coal-Bearing Massifs of the Donets Basin

Abstract

Determining the regional and local peculiarities of methane gas distribution in the coal-bearing massifs of the Donets basin will help solve several important problems at once: creating safe conditions for mining operations, using methane as an alternative fuel, and improving the environmental situation in technologically loaded regions. Local gas-saturated systems of coal-rock massifs combining individual coal seams and their host rocks are primarily the result of accumulation and minimal impact of the following geodynamic processes. Important characteristics of rocks and coal as natural gas reservoirs are porosity and gas permeability. Changes in the initial indicators of coal substance indicate a deep transformation that coal seams undergo under fluid dynamic impact, which is determined by regional and local changes in the coal-bearing massifs of the basin.
 Gas content and gas migration in different strata of coal-bearing massifs are related by age and quality characteristics. The qualitative characteristics of the gas mixture of coal deposits are constantly changing along the section and dip of the seam and are particularly distinct in tectonically disturbed areas of coal massifs. All components of the gas mixture of coal seams are controlled by a mosaic of physical parameters of its various parts, both in the undisturbed and in the mined massif. Structural, shielded deposits are often found in relatively undisturbed mine massifs and can be developed as a local gas field. Depending on the condition of the coal and gas reservoir, the gas component can vary widely. During active maximum gas recovery, a large amount of heavy and unsaturated hydrocarbons rise in the workings, which can provoke gas-dynamic phenomena.
 On the basis of isotopic and geochemical studies of gas mixtures of coal-rock massifs, the polygenetic composition of natural gas in coal-bearing strata of the Ukrainian coal basins is substantiated and proved.