New Zealand’s deep water frontier

Category Petroleum Geology
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Uruski, Christopher Ian
Holding Date 07 October 2008

Ninety percent of the New Zealand mini-continent is submerged. The ten percent which is land was elevated as a result of deformation along the modern boundary between the Australian and Pacific plates. Despite continuous Neogene deformation of the onshore and nearshore regions which has compromised accessible sedimentary basins, New Zealand is currently 50% self-sufficient in oil and 100% self-sufficient in gas. New Zealand is almost totally surrounded by large sedimentary basins, most of which lie in deep water beyond the shelf edge in depths of 200 to 2000 metres.
The move into deep water is driven by the possibility of new large oil discoveries in petroleum systems largely unaffected by deformation related to the modern plate boundary.
Recently, Exxon-Mobil and OMV acquired exploration permits in the Great South Basin, while exploration efforts are moving into deeper waters all around New Zealand. Almost every new seismic line acquired seems to expose more extensive and thicker sedimentary successions than had previously been known. New components are being added to the geological jig-saw puzzles. For example, most of New Zealand’s Late Cretaceous rocks were deposited by fluvial systems and a large Late Cretaceous delta has recently been discovered in the Deepwater Taranaki Basin, giving greater understanding of the Late Cretaceous sedimentary system. On the East Coast of North Island, two large, little deformed basins have been delineated, each of which contain up to 13000 metres of sedimentary fill. Marine Cretaceous and Neogene turbidite systems are illustrated by new data.
Similar to the land area of New Zealand, it’s petroleum potential is only 10% visible. There are many challenges in store for oil explorers both geological and meteorological, and many of these challenges are currently being met. It is the author’s opinion that New Zealand could be Australaia’s answer to the North Sea.