New Delhi: Reliance Industries has slashed natural gas reserves in its main production gas fields in the Krishna Godavari basin D6 block by 70 per cent to 3.10 Trillion cubic feet (Tcf) due to "unforeseen geological surprises".
Minister of State for Petroleum and Natural Gas RPN Singh told the Lok Sabha in a written reply that RIL had estimated 10.3 Tcf of recoverable reserves in the Dhirubhai-1 and 3 (D1&D3) gas field in the KG-D6 block.
"Subsequently, the contractor (RIL) revised the estimates of recoverable reserves of D1&D3 fields as 3.10 Tcf," he said.
D1&D3, the biggest of the 18 finds RIL has made in the deep-sea block in Bay of Bengal, had begun production in April 2009 and had produced 2 Tcf of gas during past three years.
MA oilfield in the same KG-D6 block was estimated to hold 681.4 Billion cubic feet (Bcf) of recoverable gas reserves and RIL has now revised the numbers to 788 Bcf, he said.
Singh said the block KG-DWN-98/3 or KG-D6 produced 15.106 bcm of gas in 2009-10 which rose to 20.4 bcm in 2010-11. But in the subsequent year, it fell to 15.611 bcm.
The fall in output was because one-third of the 18 gas producer wells in D1&D3 fields "ceased to produce gas due to water/sand ingress in well bores," he said, adding on MA field, two of the six wells had ceased due to same reasons.
"The operator (RIL) has attributed lower gas production as compared to approved plan from D1&D3 fields to unforeseen geological surprises and reservoir," Singh said.
The Directorate General of Hydrocarbon has attributed the fall in output to "non-drilling of the required number of gas producer wells in D1&D3 fields by the contract in line with the Addendum to Initial Development Plan (AIDP)," he said.
In the AIDP, RIL had committed to drill 31 wells and produce 80 million standard cubic meters per day of gas by this time of the year. But, output is currently less than 29 mmscmd.