Hydrocarbon Generation Potential of Shale Gas from Auranga Basin, Jharkhand

There is a growing demand for energy which has given impetus to shale gas- a very significant unconventional source of energy. Authors have investigated the hydrocarbon generation potential of Auranga basin in the western flank of Damodar valley in Jharkhand, India. They have taken twenty borehole shale samples for the study through rockeval pyrolysis (REP). They have studied important parameters thermal cracking viz.S1, S2 and S3 under REP, total organic carbon (TOC), hydrogen index (HI), oxygen index (OI), production index (PI) and genetic potential (GP). These parameters have shown amount, type and thermal maturity of organic material of shales investigated. These investigations point towards the presence of kerogen type III or type II-III admixed material having fair to excellent source of hydrocarbon generation (TOC >2wt%). The Tmax ranges from 422 - 468 ˚C indicating shale samples to be immature to even mature in nature. The relation between Tmax and production index shows most of the samples falls under hydrocarbon generation stage. The maturity of organic matter belonging to Barakar Formation varies in broad range from immature to mature. HI varies from 94-298 mg HC/g TOC showing samples are capable of generating oil and gas upon thermal cracking.S2 curve under REP placed in broad range from 1.85 -28.29 mg HC/g rock exhibiting shales to be poor to very good source rock. The relation between fixed carbon and TOC appear to be good and it may be a significant parameter for assessing organic richness of shales.

Keywords: Hydrocarbon generation potential, rock eval pyrolysis, Auranga basin, Jharkhand