EconomyNext – Two years of studying seismic and test well data and modelling has revealed Sri Lanka’s offshore Mannar Basin has sedimentary deposits that are thick and old enough to yield high quality oil and gas.
"The good news is that it’s quite thick. The Mannar Basin has 10-12 km sedimentary thickness. And it’s quite old," declared Saliya Wickramasuriya, Director General of the Petroleum Resources Development Secretariat.
"That combination of thickness and age indicates potential for hydrocarbon generation. In the last two years the modeling we’ve done indicates very prolific source rock with potential to deliver high quality oil and gas.
"We’re looking at an area of extreme promise because it shares sedimentary origin with the world’s most prolific deepwater oil and gas fields," he told a recent forum, referring to big gas deposits discovered recently in Mozambique and Tanzania.
The island was part of a ‘super-continent’ and the immediate neighbor of what are now these east African countries, which now have made the world’s largest gas discoveries, millions of years ago before being separated by continental drift.
"The Mannar Basin sedimentary formation was formed along with them," Wickramasuriya explained.
The test wells drilled by Cairn India – Dorado and Barracuda – where gas was found went only halfway down into the Mannar Basin, meaning there was more potential deeper.
PRDS modeling shows oil deposits formed closer to the island’s narrow continental shelf and gas in deeper water.
"This resource base is quite conservative," Wickramasuriya said, referring to Cairn’s two discoveries. "It does not capture the entire potential. That indicates we have substantial supply for future generations to use."
Both wells can yield about two trillion cubic feet of natural gas.
"India’s current proven gas reserves are just about 65 trillion cubic feet," Wickramasuriya said. "The recent gas find in Mozambique – our neighbor 200 million years ago – a single gas discovery spread out in three fields has 100 trillion cubic feet. Sri Lanka has two trillion cubic feet."
Cairn has been in lengthy talks on a price for natural gas before starting commercial drilling with the PRDS which is trying to formulate an energy policy that would be used for future exploration and production.