New Zealand to Release Northland Basin Data for 2004 Bidding

Preparations for a competitive petroleum exploration permit bidding round in 2004 over an area offshore Northland Basin have begun with a substantial data-package to be produced on the basin's petroleum prospectivity, the New Zealand Associate Minister of Energy, Hon Harry Duynhoven has announced.

Crown Minerals has joined forces with the Institute of Geological and Nuclear Sciences (GNS) and UK-based seismic contractor Spectrum Energy & Information Technology Ltd to produce a data-package, initial interpretation of which suggests a previously unsuspected petroleum system.

Spectrum, which has been granted a one year prospecting permit PPP 38615 over much of the offshore Northland Basin, has agreed to reprocess 9100 km of existing 2D seismic.

Spectrum has also entered into an agreement with GNS who will prepare an interpretation and hydrocarbon potential report, based on the reprocessed seismic. This data will provide explorers with an understanding of the stratigraphic framework, petroleum systems, play concepts, and trap types of the Northland Basin.

The package will incorporate a revised understanding of the basin's nearshore potential by using recently released data obtained from the deepwater Wakanui-1 well, drilled off the continental shelf in 1999 by Conoco and partners.

The data to be reprocessed are a 1600 km 1982 survey, and the 7500 km 1995 survey. Test lines are already showing significant enhancements in data quality and imaging over the original processing.

This is largely due to pre-stack time migration, advanced de-multiple techniques, more detailed velocity analyses and improved post-stack migration.

Initial interpretation from Wakanui-1 showed that the Wakanui structure is not buried by marine Cretaceous rocks as previously believed. The presence of a Middle Jurassic coal measure succession strongly suggests the presence of a new previously unsuspected petroleum system.

Seismic data suggests that the depocentre to the east of the Wakanui structure contains both Jurassic and Cretaceous source rocks. Thermal modelling suggests that they are buried deep enough to be generating and expelling hydrocarbons.

Reprocessing should be complete by January 2004, following which the interpretation report will be completed ahead of the anticipated bid round.