Petrophysical Investigation of Hydrocarbon Generation Potential of Coal from Raniganj Basin, India

Abstract

Methane content in a coal seam is a necessary parameter for evaluating coal bed gas, and it is a threat to underground coal mining activities from environmental aspects. Keeping in pace with comprehensive studies of coal bed gas, the authors had selected 12 coal samples from the Sitarampur block of Raniganj Coalfield. The Petrographic examination illustrated that significant values of reactive macerals present in samples demonstrate that organic matter is dominated by kerogen Type III, making it suitable for 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 also validated by the cross plot between atomic H/C and O/C. The plots between the H/C and O/C ratio in the Van Krevelen diagram indicate that the coal samples lie in the type III kerogen, and bituminous coal (gas prone zone) is present in the block, which 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.