Positive Signs for Reinga Basin
Friday 5 March 2010, 8:28AM
By GNS Science
579 views
The Reinga Basin, off the northwest coast of the North Island, is one of the most prospective frontier basins in the New Zealand region, a report by Crown Research Institute GNS Science says.
The report, commissioned by the Crown Minerals division of the Ministry of Economic Development, is based partly on 5000km of high quality two-dimensional seismic reflection data acquired in 2009 by Crown Minerals in partnership with petroleum services company CGGVeritas.
Other components in the investigation were satellite data of sea surface slicks and knowledge of the geology in the adjacent Northland and Taranaki Basins.
The analysis shows that Reinga Basin contains potentially oil-bearing sedimentary rocks that are up to 7km thick and it has all the elements needed for a working petroleum system. Its rock sequences are similar to those in the Taranaki Basin.
Lead author of the report, Vaughan Stagpoole, said a reconnaissance seismic survey in the 1990s indicated the area was potentially prospective for oil and gas. This prompted a follow-up industry-standard survey in 2009.
“When we examined the 2009 seismic data, there was clear evidence of petroleum expulsion zones, which means there is an active petroleum system in the basin,” Dr Stagpoole said.
The geology in the 150,000sqkm Reinga Basin is less complex than the adjacent Northland Basin, making it more attractive to explore. However, it is further from land and in slightly deeper water – typically between 1700m and 2000m - which can be a challenge for explorers.
Early in 2010 the government opened bidding for blocks in the Reinga Basin. The blocks offer will close in August, at the same time as a blocks offer closes for the adjacent Northland Basin. Permit-holders are likely to be announced in late 2010.
The Reinga Basin prospectivity report, the latest in series of such reports on New Zealand frontier basins prepared by GNS Science, is being used by Crown Minerals to help promote Reinga Basin to exploration companies internationally.
Dr Stagpoole said government-acquired data over previously unexplored areas had increased the attractiveness of these areas for oil exploration companies.