ONGC has created an exploration landmark when gas flowed out from the Barren Measure shale at a depth of around 1700 m., in its first R & D well RNSG-1 near Durgapur at Icchapur, West Bengal on 25th of January, 2011. 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 U.S and Canada. The well RNSG-1 drilled down to a depth of 2000 m. The Barren Measure Shale, which is the main target, was encountered from 985 to 1843 m. This well was spudded on 26th September 2010.
Shale gas is one of the predominant unconventional natural gas and major source of onland gas particularly in US and Canada. In USA, Shale gas production contributes to nearly 17% of the total gas production.
This breakthrough has been made possible as a result of systematic studies being made at KDMIPE, a premier R & D Institute of ONGC in many of the shale formation in the different sedimentary basins where ONGC has its presence for its conventional oil and gas activities. 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 prioritized 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 R & D wells in Damodar Basin- two wells in Raniganj sub-basin in W.Bengal, and two wells in N.Karanpura sub-basin in Jharkhand, was operationalized through the help of M/S Schlumberger, who were given an integrated contract for drilling, assessing and carrying out the relevant operations including hydro-fracturing in view of their expertise in US. Relevant permissions were taken from the Ministry of Petroleum and Natural Gas for carrying out such an operation. The estimated expenditure is about Rs 168 Cr., and the total project is expected to be completed within 520 days.
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.
Source: ONGC, February 4, 2011;