Essar Oil Limited (EOL) is likely to commence production of shale gas at its Raniganj coal bed methane (CBM) block soon. Meanwhile, EOL is planning to invest an additional Rs 10 billion in the Raniganj facility this year to increase production from 1 million metric standard cubic metres per day (mmscmd) of CBM to 3 mmscmd. The company has already invested Rs 33 billion in the facility.