Geochemical investigation of hydrocarbon generation potential of coal from Raniganj Basin, India

Abstract

AbstractMethane content in a coal seam is a necessary parameter for evaluating coal bed gas, and it poses an environmental risk to underground coal mining activities. Keeping in pace with comprehensive studies of coal bed gas, 12 coal samples were selected from the Sitarampur block of Raniganj Coalfield for analysis. The Petrographic examination illustrated that significant values of reactive macerals present in samples demonstrate that organic matter is dominated by the prominent source of aromatic hydrocarbons with a minor proportion of aliphatic hydrocarbon, which falls in the region of (Type III) kerogen, confirms the suitability for the potential of hydrocarbon generation. “A” factor (aliphatic/aromatic bands) and “C” factor (carbonyl/carboxyl bands) value concluded that the sample has the lowest aromaticity and the highest hydrocarbon-generating potential, which was also validated by the Van Krevelen diagram. The Van Krevelen diagram plots between the H/C and O/C ratio indicate that coal samples lie in the type III kerogen, and bituminous coal (gas prone zone) is present in the block, which is confirmed by the cross-plot between desorbed and total gas (cc/g). The in situ gas content values are high enough to produce methane from coal beds. The overall study concludes that the Sitarampur block from Raniganj Coalfield is suitable for hydrocarbon generation and extraction.