Exploration of the Offshore East Coast Fold and Thrust Belt Basin of North Island, New Zealand: An Emerging Petroleum Basin

Chris Uruski, B. D. Field, and R. Funnell
Institute of Geological and Nuclear Sciences Ltd, Lower Hutt, New Zealand

New Zealand's East Coast fold and thrust belt basin contains 15,000 metres of sedimentary fill and overlies a modern subduction system. The basin covers more than 70,000 km2 and a sedimentary history extending back to the Albian.

Three phases of exploration, starting in the 1960s, resulted in three offshore wells, all of which encountered significant but sub-economic gas. Hawke Bay-1, drilled in 1976 and Titihaoa-1, in 1993 were not tested due to a combination of factors, but at the time the giant Maui field was then supplying most of New Zealand's gas needs. Tawatawa-1 was drilled in 2004 and, while elevated gas readings were recorded, reservoir quality was poor.

Reservoir facies are abundant in the East Coast Basin. But, modern, good quality seismic data are essential to allow sequence stratigraphic interpretation. Active structures undoubtedly controlled their distribution.

A new phase of exploration is about to start driven by a New Zealand government plan to acquire a 4000 km, high-spec 2D survey covering currently open acreage and aimed at high-resolution imaging of sedimentary bodies. The data package will be released free of charge in conjunction with a licencing round. This paper will present the initial results of that survey.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005