Citing "unforeseen geological surprises", Mukesh Ambani-led Reliance Industries Ltd (RIL) has slashed natural gas reserves estimate of its main production fields in the Krishna Godavari (KG) basin D6 block by 70% to 3.1 trillion cubic feet (tcf).
Minister of state for petroleum and natural gas RPN Singh told the Lok Sabha in a written reply on Thursday that RIL has revised the estimate of recoverable reserves of the Dhirubhai-1 and 3 (D1&D3) gas fields as 3.10 tcf against the earlier estimated 10.3 tcf.
The D1and D3 gas fields are the biggest of the 18 finds that RIL has made in the deep-sea KG-D6 block in the Bay of Bengal.
RIL began production from these blocks in April 2009 and had produced 2 tcf of gas during the past three years.The MA oilfield in the same 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.
The KG-D6 block produced 15.1 bcm of gas in 2009-10 and 20.4 bcm in 2010-11. But in the subsequent year it fell to 15.6 bcm.
The fall in output was because wells in the D1&D3 fields "ceased to produce gas due to water/sand ingress in well bores," Singh said.
"The operator (RIL) has attributed lower gas production compared to approved plan from D1&D3 fields to unforeseen geological surprises," said Singh.
On his part, the directorate general of Hydrocarbon has attributed the fall to "non-drilling of the required number of gas producer wells in D1&D3 fields by the contract in line with Addendum to Initial Development Plan."
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. However, the current output is less than 30 mmscmd.