There were positive signs of potential oil and gas reserves in the southern sea belt of Sri Lanka from Galle to Hambantota as revealed by a recent seismic survey conducted by the Petroleum Development Secretariat of the Ministry of Petroleum and Petroleum Resource Development, highly placed official sources told the Sunday Observer.
Explaning the latest Developments in the survey, Director General PRDS, Dr. Neil R De Silva said the preliminary data collected using the seismic vessel Geonatuna showed presence of sedimentary rocks in the southern sea belt in the country.
Oil and gas commonly known as petroleum, are generated in sedimentary rocks.
Remains of tiny oceanic creatures and plants buried under several kilometres of sediments will get converted to oil and gas under high pressure of temperature.
At the initial stages of petroleum exploration gravity surveys are commonly used to locate areas of thick sedimentary rocks called sedimentary basins, where right conditions for the generation of petroleum are found, he said.
He said that gravity surveys are relatively cheap compared to seismic surveys. He said that the satellite gravity data in the region show two gravity anomalies offshore south of the island from Galle to Hambantota.
A gravity anomaly could result from several geological phenomena and the presence of a sedimentary basin is one of them.
Therefore the PRDS decided to collect reconnaissance 2D seismic data over these gravity anomalies to verify whether they could have been produced by the presence of sedimentary basins. 2D seismic profiles produced by collecting and processing sound waves reflected from rock layers below the sea bed, provide a cross-section of the earth where presence of sedimentary rocks could be verified, he said.
He said that from last week of February approximately 600 km of 2D seismic data were collected by Geonatuna seismic vessel crew and the seismic crew from PRDS.