ECONOMYNEXT – UK-based BellGeospace has completed 60 percent of an aerial gravity magnetic survey in the shallows of Mannar and Cauvery basins and will be licensing the data to oil prospectors after processing, officials said.
Ship borne seismic surveys have been conducted over several decades in the Northwestern and Northern waters of Sri Lanka, and Cairn India also found traces of natural gas in wells dug in the Mannar basin in 2011.
“Because of the seas around Sri Lanka is deep, doing seismic surveys from ships is most suitable,” Surath Ovitigama, Director General of Sri Lanka’s Petroleum Development Secretariat said.
But in the north of island is the Cauvery Basin. That is from Mannar Island going north that is mostly shallow water.
“It is not suitable for ship based seismic surveys. The most suitable for that area is airborne gravity magnetic survey.”
“We have been trying to do it for a while, because in the north, we do not have any new data about the north to interest prospective investors.”
The information on subsurface structure in the north of the island that Sri Lanka had dated back to 1984.
Compared with the technology available today, that data is not very useful,” Ovitigama said.
BellGeospace is doing the survey at their own costs, and is planning to recover their investment by licensing the data to prospective investors and split part of the profits with Sri Lanka.
“Why do they come taking a financial risk? This is because they believe Sri Lanka has gas and oil resources,” Ovitigama said.
“That is why they think they can license and get the money.”
Bell Geospace is using a Basler BT-67, a converted DC-3 aircraft fitted with turboprop engines and avionics to do the surveys.
“We are a totally passive airborne platform,” Andrev Joseph Searle. “We typically fly early in the morning when conditions are calmer for data acquisition. Our flights last six hours.”
“We have completed nearly 60 percent of the current project. The aircraft and scientific equipment are operating well operating very well. The data we have acquired so far is of excellent quality.
The aircraft will acquire magnetic data and full tensor gradiometry data, which measures the rate of change of gravity in all directions of the field, caused by subsurface geology.
The data will be processed to build a model of the sub-surface geology.
“We are confident that once fully processed it will provide far better, and more detailed sub-surface 3D imaging and therefore increase the understanding of entire survey area,” Searle said.
Sri Lanka has split an earlier 20 exploration blocks into smaller units to make it more affordable for oil prospector to come and search for oil, Petroleum Minister Udaya Gammanpila said. (Colombo/Sept20/2021)