Survey reveals Andaman prospectivity

Spectrum has re-processed 10,600 line km (6,586 mi) of new 2D seismic data taken off the Andaman Islands offshore eastern India.

Offshore staff

OSLO, Norway -- Spectrum has re-processed 10,600 line km (6,586 mi) of new 2D seismic data taken off the Andaman Islands offshore eastern India.

The findings reveal several new structures and areas of interest, the company says, and potential analogues with adjacent basins.

The multi-client funded data-set covers 245,000 sq km (94,595 sq mi) in the Andaman Sea, over part of the Andaman Sea basin. Data was reprocessed in both time and depth using techniques including Surface Related Multiple Elimination, High Resolution Radon Demultiple, Kirchhoff Pre-Stack Time and Depth Migration, and noise attenuation techniques.

Main issues that Spectrum’s geophysicists had to address included complex shallow geology (reefs and limestones) and steeply dipping events with angle and direction of dip varying greatly within very small areas, resulting in complicated ray paths. The survey improved imaging of the entire seismic section, in both shallow and deep sections.

The Andaman Sea basin is bounded by the mature hydrocarbon provinces of Myanmar to the north and Indonesia to the south. Spectrum says the Indian section of the Andaman Sea basin can be classified as frontier, with just 15 wells drilled to date. All targeted the shallow water part of the fore-arc basin and most were drilled close to the Andaman Islands.

Of these wells, the first (AN-01-1) discovered gas shows in Miocene limestones. Spectrum says this discovery proves the presence of working hydrocarbon systems with generating hydrocarbon source systems, reservoir, and seal horizons, as well as migration and trapping mechanisms.

Reprocessing of the new data indicates that the Andaman Sea basin contains all necessary elements for successful hydrocarbon exploration. These include probable source, reservoir, and seal intervals; structural and stratigraphic trapping geometries; direct hydrocarbon indicators such as gas clouds, bright, and flat spots; and bottom simulating reflectors indicating the presence of gas hydrates.

Andy Cuttell, Spectrum’s VP of Data Processing, said: “The exploration focus is turning to this frontier area, with the recent award of further exploration licences in the Andaman region. The reprocessed seismic data will provide explorationists with vital regional structural and stratigraphic insight to de-risk an area which is hoped to provide future high impact hydrocarbons.”

08/11/2010

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