‘No coal-based methane extraction in Neduvasal’

Published : Mar 15, 2017 12:30 IST

Pawan Kumar, Group General Manager-Basin Manager, Cauvery, of ONGC, rubbing crude oil on his hands to dispel fears of toxicity.

Pawan Kumar, Group General Manager-Basin Manager, Cauvery, of ONGC, rubbing crude oil on his hands to dispel fears of toxicity.

“WE are not in the business of producing coal-bed methane or shale gas in Tamil Nadu,” said Pawan Kumar, Group General Manager-Basin Manager, Cauvery, of the Oil and Natural Gas Corporation (ONGC). “Coal-bed methane is extracted from a coal seam and this coal is not available in the subsurface in the Neduvasal area,” he told Frontline on March 6 in response to a question about the fears of farmers of Neduvasal and other villages that coal-bed methane and shale gas would be produced under the guise of hydrocarbon extraction.

“There is no scope for exploitation of coal-bed methane in the Neduvasal area because there is no coal there. Specific types of shales are required for producing shale gas, which are absent in the Neduvasal area,” he said. Moreover, the Centre and the State government had clearly spelt out in their policy that there would be no shale gas or coal-bed methane production in Tamil Nadu. “We will not even go in for research and development or do any project in the name of coal-bed methane or shale gas in Tamil Nadu,” he said. The Centre had given this in writing to the court and the National Green Tribunal, he said.

P. Chandrasekaran, Group General Manager-Basin Manager, Krishna-Godavari-Pranahita Godavari, ONGC, said separately that “there is no potential for shale layer for shale gas” exploitation the Neduvasal field.

Shale gas is natural gas trapped within shale formations. Shales are tight, clayee, sedimentary rocks, which are a rich source of petroleum and natural gas in a conventional oilfield. Shale gas consists mainly of methane. A combination of horizontal drilling and hydraulic fracturing is used to extract shale gas. Methane is harmless in the prevalent concentrations in the atmosphere. Methane is the main constituent of petroleum natural gas.

Pawan Kumar, who took part in the talks with leaders of the Save Neduvasal Struggle Committee in Madurai on March 4 in the presence of Union Minister Pon. Radhakrishnan, said ONGC had “explained that groundwater would not get affected by oil and natural gas exploration because the groundwater that is tapped is available up to a depth of only 300 metres. But in Neduvasal and other areas, we produce oil and gas at a depth of 2,000 m or more.” In Neduvasal-2 [Nallandar Kollai], oil was found at a depth of about 2,030 m. In the Cauvery basin, oil can be found anywhere between 1,500 m and 5,000 m.” Since oil was extracted at depths of more than 2,000 m in Neduvasal-2, and the well was cased at multiple levels, “there is no chance of groundwater getting contaminated”, he said. No chemical was used other than “Bentonite” as drilling fluid while drilling the uppermost water table section, which is normally between 200 m to 500 m below the surface. ONGC’s Cauvery asset used non-toxic water-based drilling fluid as per the norms of the Union Ministry of Environment and Forests.

Pawan Kumar said: “Flaring of gas is burning of excess gas during testing until pipelines are laid to reach consumers or the nearest gathering station. It is controlled burning of gas just as it is done in a kitchen. Flaring of natural gas is the safest way of disposing of hydrocarbon gas because it will be harmful to release it directly into the atmosphere.” On the Neduvasal farmer G. Subramanian’s allegations that the local Tahsildar, the Village Administrative Officer, the Revenue Inspector and ONGC officials coerced him to part with his land, Pawan Kumar said ONGC never did any “arm-twisting” to make people lease their land. It has only tried to convince them that it was doing its work in the interest of the nation.

On the seepage of crude oil to the surface from the well drilled at Vanakkankadu, Pawan Kumar said ONGC drilled the well in 1994 but it did not produce oil in commercial quantities. So the well was declared dry and abandoned. ONGC engineers installed two cement plugs, each more than 100 m deep, in the well and steel pipes and plates were cut at the surface to prevent oil from reaching the surface. The land was handed back to the owner. “There may have been some seepage in all these 23 years but it was brought to our notice only recently,” he said.

Pawan Kumar dismissed allegations that production of crude oil would cause cancer to people living in the vicinity. He asked his staff to bring the crude discovered at Madanam (in Nagapattinam district) and rubbed it on his hands to show that it had no harmful effects. “Our uniforms are wet with oil when we work in rigs. It does not cause cancer,” he said.

Since ONGC did not taken part in the bid for DSFs, it was not required to hold any public hearing in Neduvasal, he said.

Pawan Kumar said ONGC had been operating in the Cauvery delta region for close to 50 years without any major incidents. It had discovered 31 fields in the State and most of them were producing oil and gas. Oil wells were drilled on land at Karaikal, Kovilkalapal, Narimanam, Thirukkalar, Adikkamangalam, Kamalapuram, Tiruvarur, Madanam, Pandanallur, Neyveli, and so on, and off shore at PY-1 (Puducherry 1&3), PH-9 (Palk Bay High) and PBS-1 (Palk Bay Shallow).

A press release dated February 27 from the Ministry of Petroleum and Natural Gas said about 600 tonnes of oil and 30 lakh cubic metres of gas were produced every day from the 31 fields in Tamil Nadu. Gas is used to generate 750 megawatt of electricity in the State. “Till date, more than 700 wells have been drilled to extract oil and gas in Tamil Nadu. These active operations are not hampering agriculture in nearby areas and do not have any known environmental impact or cause health hazards in the operational area,” it said.

T.S. Subramanian

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