The Ministry of Environment and Forest (MoEF) has granted the Terms of Reference (ToR) to Vedanta Ltd’s Cairn Oil & Gas, to carry out Environment Impact Assessment (EIA) for drilling a total of 274 offshore and onshore oil and gas exploration wells in the Bay of Bengal, Nagapattinam, Karaikal, Villupuram and Puducherry.

The sanction letter with the ToR to proceed with the EIA was issued to the company on Saturday and Sunday, kickstarting the first step in the process.

Vedanta proposes to drill 116 exploratory and appraisal wells in project block 1 and 158 wells in project block 2.

The depth of the drilling wells will be between 3,500 and 4,500 metres each. The project is just 0.49 km from the Pichavaram mangrove forest.

Densely populated

Densely populated areas such as Poompuhar, Karaikal, Nagapattinam and Velankanni are located in the block.

A number of rivers also run through the project block. In 2017, Vedanta was allocated licence for hydrocarbon exploration and production by the Ministry of Petroleum and Natural Gas, under a revenue-sharing contract.

First block

The first block covers an area of 1,794 sq.km, of which 1,654 sq.km is offshore in the Bay of Bengal and 141 sq.km is onshore — 139 sq.km in Villupuram and 2 sq.km in Puducherry.

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The second block covers 2,574 sq.km consisting of 142 sq.km in Nagapattinam, 39 sq.km in Karaikal and 2,393 sq.km of sea portion of the Bay of Bengal, according to the submissions made by the company to the MoEF while applying for grant of ToR.

The ToR for carrying out an EIA is the first in a series of steps that need to be completed and certified for setting up a project. The EIA will study the environmental impact of the project, explain the consequences and the mitigation measures to be undertaken. Approval for carrying out the EIA is no guarantee of a project being granted the final nod, but generally, it is granted clearance, unless the reasons are too difficult to justify.

"Under the provisions of the EIA Notification 2006, as amended, the Standard ToR for the purposes of preparing the environmental impact assessment report and the environment management plan for obtaining prior environmental clearance is prescribed with public consultation," the Ministry said in a letter to Vedanta.

Commercial exploitation

The company, while submitting details of the project to the MoEF, said exploratory drilling is a temporary project of short duration, and there could be commercial exploitation if there is a discovery of a hydrocarbon field. "Vedanta Ltd. (Cairn Oil and Gas) has planned to carry out seismic data acquisition, exploration and appraisal well drilling and well testing in the CY-OSHP-2017/2 Block over a period of 10-12 years. The estimated cost of the project is given below: physical Surveys Cost estimated to be approximately ₹106.63 crore. The average cost per well for exploratory & appraisal well is estimated to be ₹49 crore," the company said in its submission for the second block.

In the last two months, the ONGC has been granted ToR for the EIA to carry out exploratory drilling for 17 wells in Bhuvanagiri in Cuddalore and 10 wells in Periyakudi in Thiruvarur district. The project is estimated to cost ₹2,450 crore for the Bhuvanagiri field and ₹1,300 crore for the Periyakudi field. The company also plans to drill 35 wells in Cuddalore and 5 wells in Nagapattinam.