Crown Minerals geophysicist Ricardo Bertolotti today described the 3160km, 2D survey – acquired by Swire Pacific’s Pacific Titan vessel during February and last month – as a “resounding success”.

“We accomplished all our goals and achieved more than we expected. With this new data we can already see the area has more potential than thought in the past,” Bertolotti told EnergyReview.net from Wellington.

Bertolotti said there were some similarities between the Great South Basin and the North Sea – both were distant, deepwater regions that could suffer atrocious weather conditions.

He said it appeared the Great South Basin and neighbouring Canterbury Basin were related “in a bigger way than in the past”. Hopefully, further interpretation of the latest data would confirm this, he added.

“Looking at the raw data suggests that the GSB extends to the north-east, providing potential for hydrocarbon prospectivity,” Bertolotti said.

The survey, known as DUN06, included a grid off the coast between Dunedin and the Catlins, as well as lines that extended into the heart of the Great South Basin.

The latest survey was the second government-sponsored seismic survey after last year’s offshore East Coast survey and part of its $NZ15 million ($A12.5 million) package of exploration incentives aimed at further stimulating and accelerating exploration in areas outside the Taranaki Basin.

Bertolotti said the Great South Basin was a simpler system than the offshore East Coast. Whereas the East Coast had been a difficult tectonically-compressed system, the Great South Basin had easier structures to map and was therefore less risky.

He said the Crown Minerals survey updated 30-year-old data, most of which was shot for Hunt Petroleum in the early 1970s.

“This new data will complement the Hunt data by providing better imaging of the geology through to basement than was previously available,” he said.

Bertolotti said there was already some strong evidence that the Great South Basin could be a prolific petroleum producer.

“We also tied the seismic to five wells, the most important of which was the Kawau-1A well that was a gas discovery. Also, the Tara-1 and Toroa-1 wells both had strong oil and gas shows but were not tested for technical and other reasons,” he said.

Kawau-1A had proven reserves of 500 billion cubic feet of gas.

GNS Science is expected to finish processing the new survey data by August. GNS Science is also reprocessing about 8000km of existing 2D seismic data.

Bertolotti said both sets of data would be distributed freely to interested parties, as well as results from an enhanced well data project that was finished in early February.

Crown Minerals is opening up great swathes of the Southern Ocean off New Zealand and is expected to officially open the 40-block Great South Basin Blocks Offer later this month.

The Pacific Titan arrived at Port Taranaki late last year to start one of the biggest multi-company petroleum exploration programs in New Zealand waters. Norwegian company Multiwave Geophysical, which has contracted the vessel, is now about halfway through acquiring more than 10,000 km of 2D seismic over four offshore geological basins for 10 different operators.