Conoco plans further Northland drilling

By Mark Reynolds

Further exploration of an oil and gas prospect off Northland is planned, despite the failure of an exploration well there last month.

A consortium headed by Conoco of the United States will review exploration results in preparation for a further well to be drilled in the 48,000 sq km site. But it could be three years before the next well is drilled.

Conoco is re-evaluating the area after its wildcat Wakanui-1 well about 150 kilometres northwest of Auckland failed to find oil or gas in commercial quantities.

The well cost Conoco and its partners, including the Todd family of Wellington, about $US19 million. The consortium is being tight-lipped about whether any signs of oil or gas were discovered, but the partners are undertaking further studies to pinpoint a second drilling site. Under an exploration licence with Crown Minerals, the partners are committed to drill a further well by April 2003.

Petroleum geologist Rick Herzer of the Institute of Geological & Nuclear Sciences said the unsuccessful well did not detract from offshore Northland's potential to be a commercially producing area.

The Northland Basin was only lightly explored by international standards and contained the right conditions for hydrocarbon generation, he said.

"From our reconnaissance surveys the basin appears to contain geological structures, both inside and outside the Conoco licence area, that could be favourable petroleum reservoirs," he said.

"We believe that with more exploratory drilling, offshore Northland could match Taranaki for hydrocarbon production."

The Northland Basin has received relatively scant attention in the history of the search for oil and gas in and around New Zealand. The first systematic seismic survey of the area did not occur until 1982, and the remoteness of the area and deepwater conditions discouraged follow-up investigations.

Conoco and its joint venture partners, the Todds and Indonesia Petroleum of Japan, acquired a 7500 kilometre seismic survey of the prospect in late 1995, which identified a number of potential oil reservoirs.