In a major breakthrough, state-owned Oil and Natural Gas Corporation (ONGC) today said it has struck natural gas reserves in its maiden well drilled to tap shale gas in West Bengal.
This is the first time gas has been discovered in sedimentary shale gas rocks outside the US and Canada.
"ONGC created an exploration landmark when gas flowed out from the Barren Measure shale at a depth of around 1,700 meters, in its first R&D well RNSG-1 near Durgapur at Icchapur, West Bengal," the company said in a statement here.
Though the well is still under assessment, the breakthrough is significant as India is the first Asian country where gas was discovered from shale outside US and Canada.
"The well RNSG-1 was drilled down to a depth of 2,000 meters. The Barren Measure Shale, which is the main target, was encountered from 985 to 1,843 meters," it said.
Shale gas is one of the predominant unconventional natural gas and major source of onland gas particularly in the US and Canada. In US, shale gas production contributes to nearly 17 per cent of the total gas production.
As per the initial studies, many shale sequences in well explored basins are found to be promising like Damodar, Cambay, and Krishna Godavari and Cauvery basins. The potentiality of these basins was also vetted by international experts.
However, Damodar Basin, where ONGC already has its presence for CBM, was prioritised for R&D exploration in shale gas in view of the shallow nature of the shale formations, and abundant water availability - a pre-requisite for doing massive hydro fracturing.
The R&D project, which involved drilling of four wells in Damodar Basin -- two wells in Raniganj sub-basin in West Bengal and two wells in North Karanpura sub-basin in Jharkhand, was operationalised with the help of Schlumberger.
"The estimated expenditure is about Rs 168 crore and the total project is expected to be completed within 520 days," ONGC said.
The successful R&D pilot testing of first ever shale gas on surface will put India on shale gas map of the world. It has opened up new hopes for meeting our energy needs and encouraged to venture into many shale sequences in well explored Cambay, KG, Cauvery and Assam-Arakan Basins for exploitation of shale gas in Indian subcontinent.
