Prospective evaluation of hydrocarbon generation potential of Umarsar lignite, India

ABSTRACT

The organic richness, thermal maturity, oil generation potential, liquefaction behavior hydrocarbon generation potential and geochemical properties of 12 lignite samples from Umarsar lignite mines of Kutch district, Gujarat, India were investigated. The lignite samples studied shows that they are significantly rich in total organic carbon (TOC) content which varies from 36.92 to 51.99 wt%. Tmax and HI index value show that these thermally immature lignite contains Types II-III and Type III kerogen; which is also anticipated from plot between released hydrocarbon (S₂) yield and TOC. The cross plot between HI index and TOC demonstrates that the samples fall in fair oil source. The reflectance value varies from 0.23% to 0.28% and confirm it is immature in nature. The huminite maceral (>70.34%) dominates while liptinite >15.53% and inertinite occur in subordinated amount. High quantity of huminite and liptinite macerals shows its aptness towards liquid and gas hydrocarbon formation. The HI index and H/C values favor significant quality of hydrocarbon (gas and oil) potential.

KEYWORDS:

• TOC
• pyrolysis temperature
• thermal maturity
• petrographic study
• oil yield

Acknowledgments

Authors are thankful to Director, CSIR-Central Institute of Mining and Fuel Research, India for the infrastructural support and also to CSIR Network Project Coal Gas Urja (ESC-0302) for financial support. Thanks are also due to Dr. R.P. Singh (IRS, ONGC Ahmedabad) and the officials of Gujarat Mineral Development Corporation (GMDC, Umarsar) for their kind support and help during the field visit.