Oil hunters are back in the Kerala-Konkan basin. After an interval of over three years, Oil and Natural Gas Corporation (ONGC) is conducting seismic surveys in the basin to examine the geological structure of sedimentary rocks as part of its project to scout for hydrocarbon deposits. The 2D and 3D surveys have resumed after an operation held in 2009 off the Kochi coast had to be abandoned because the results were negative.
“Oil or gas is formed in sedimentary rocks. Survey vessels look for sedimentary rocks. It is like looking for life in planets. You may find a planet, but life may not exist there,” a senior official of ONGC told The Hindu. The analysis of inputs may take several weeks, based on which decisions for explorations could be made.
The Kerala-Konkan offshore basin, covering an area of around 580,000 square km., stretches from Goa in the north to Kanyakumari in the south. The basin extends from peninsular shield on the east to ‘Arabian Abyssal plain’ in the west.
The basin holds the promise of hydrocarbons, according to data with the Directorate General of Hydrocarbons. Drilling results have indicated that sediments with organic carbon content are present in the basin.
Fifteen exploratory wells were drilled in the basin so far. Some of the wells have shown the presence of hydrocarbons while drilling but ‘production testing results’ were not encouraging, according to the Directorate. Wells named ‘Kasargod-1’, ‘KK-OS-V1-1’ and ‘CSP-1’ showed ‘faint oil fluorescence’.
Wells have been drilled up to 4600 metres in the basin, characterised by the presence of an opaque layer of ‘basalt’. Only few wells have been drilled below the basalt. The fact that the structural style of Kerala-Konkan basin is similar to Bombay Offshore basin has encouraged scientists.