Global managing general partner Randall C Thompson said Wellington-headquartered GNS Science had completed its data interpretation across the company’s 55,830 square kilometre licence PEP 38451.

For the first time all available data had been incorporated into a single integrated interpretation of the basin, Thompson said.

“This new technical review shows that all of the essential elements of the petroleum system are present for successful exploration within the permit,” he said.

Thompson said thick sedimentary sections in the licence included a large delta, which contained high volumes of source rocks, excellent reservoir facies and good seals.

Source rocks included the extensive Rakopi Formation coal measures, which were the source rocks for oil in the Maui, Maari and Tui fields.

Within PEP 38451, this formation was up to 1km thick, covering almost 20,000sq.km.

Other potential source rocks included Jurassic coal measures, which were penetrated in Conoco’s Waka Nui-1 Northland well several years ago, and Cretaceous marine units.

Thompson said basin modelling showed these potential source rocks had, in the past, expelled large volumes of oil.

The GNS study also recognised that reservoir rocks, of various ages within many structures, were ideally placed to trap much expelled oil.

Thompson said GNS believed the Late Cretaceous to be a primary target horizon, containing fluvial and marine sands interleaved with coaly units in the Rakopi Formation, and marine sands in the succeeding North Cape Formation.

Secondary targets included extensive turbidite and channels deposits of Neogene age.

Two recognised structural trends were in the Late Cretaceous and the Eocene.

The largest structure mapped to date – Romney – was of Cretaceous age and in about 1600m of water.

It had an areal closure of 200sq.km and was well-placed to receive charge from nearby kitchens, Thompson said.

Its fetch area was 1725sq.km, from which 10,830 million barrels of oil could have been expelled.

Migration modelling suggested Romney could be charged with 1.1-1.65 billion barrels of oil, plus 1.7-2.7 trillion cubic feet of gas.

Nearby Coopworth was in 1400m of water and had a fetch of 521sq.km, from which 3850 million barrels of oil could have been expelled.

Its areal closure of 130sq.km meant it might be charged with 350-540MMbbl of oil, plus 0.6-1.0tcf of gas.

Corriedale lay in 230m of water in the permit’s southeast sector, had a fetch of 730sq.km, from which 1800MMbbl of oil could have been expelled.

Its areal closure 64sq.km suggested it could contain 180-280MMbbl of oil, though negligible gas.

Thompson said a new 2D seismic survey was planned, to allow more precise mapping of known prospects and leads, to confirm prospects within the Merino trend, and to investigate regions not previously covered by seismic.

“This comprehensive study has created an extremely positive light on the prospectivity of the area,” he said.

“Global is now commencing to identify and joint venture with industry partners to fund the 2D seismic survey during the first half of next year.”