Shale Gas Exploration in India: Opportunities and Challenges
ONGC, Dehradun, India
Among various unconventional gas resources; the CBM, tight gas and shale gas are being commercially exploited in US and Canada, Australia, China etc in different proportions. India too has kept pace with the CBM industry but the tight gas and shale gas are yet to find a place in the country’s energy basket.
Shale gas is contained within the shales predominantly in adsorbed form, in the micro-pores and micro-fractures in different proportions. The gas is usually thermogenic but cases of biogenic system is also reported (Antrim shale, USA).The gas is produced by inducing fracs preferably by water from multilevel completions. The pressures are generally low but the length of production period compensates by volume.
In US shale gas production was more than one Tcf/yr (2006) which is approx 14% of the US gas production. There are around 35,000 wells under production in five major established shale gas plays in US. The phenomenal success in Barnet shales has put the shale gas plays on the front line around the globe.
The shale gas exploration in India is relatively new but rapidly gaining attention of the industry players. The shales in Gondwana & Cambay basin have been field experimented for evaluating the shale gas potential. Initial results are found encouraging and at par with US producing shales. Hence it has opened vast geographical and stratigraphic frontiers for shale gas exploration. The real challenges in exploitation of shale gas lies in drilling of customized multilateral wells and completing it. The stimulations with water frac with deeper perforations, appropriate proppants and flowing gas at low pressures pose a challenge technologically without affecting the economics.
However the vast resource base coupled with rise in demand for gas and appropriate market prices make the time right to explore & exploit this resource on equal priority.
Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery