New Delhi, June 27: State-owned explorer ONGC Ltd has got an environmental clearance to drill five wells for shale gas and oil in the Krishna-Godavari (KG) basin at an estimated cost of Rs 217 crore.

ONGC had proposed further exploration of shale gas and oil in the KG basin and was examined by the environment ministry.

"The proposal was first vetted by the expert appraisal committee. Based on its recommendation, the environment ministry has given the final environment clearance to ONGC for exploratory drilling of five wells in the KG basin," a senior government official said. The approval has been given subject to certain conditions.

According to the proposal, ONGC plans to drill wells in the onland blocks in West Godavari, Bantumilli extension, Suryaraopeta, Mahadevapatnam and Mandapeta in Krishna, West Godavari and East Godavari districts to assess the potential of shale.

The project is estimated to cost Rs 217 crore. About 5-6 acres of land to drill each well will be required and the duration of drilling 90-120 days per well. All these wells will be drilled with water-base mud only, it added.

The exploratory wells are drilled to assess the presence of shale gas, which also provide leads for initiating further exploration programmes.

ONGC has been operating in the KG basin for more than 35 years.

The exploratory efforts so far have led to the discovery of 65 small-to-medium sized hydrocarbon fields with about 356 million tonnes (oil and oil equivalent gas) of initial in-place on-land reserves.

The current production of oil and gas is 750-800 tonnes per day and 2.5-3 million cubic metres of gas, respectively, from the various facilities in this area.

Since the KG basin holds significant promise for additional reserve accretion, the petroleum ministry is keen to continue the exploratory activity.

Import dependence

India's known oil and gas reserves form a mere 0.8 per cent of the world reserves of petroleum. ONGC is the largest producer of oil and gas in the country, contributing 72.4 per cent of the crude oil and 48.5 per cent of the natural gas production.

At present, over 78 per cent of India's oil requirements are being met through imports.