Deepwater Taranaki, New Zealand: structural development and petroleum potential*

Deepwater Taranaki is investigated for its petroleum potential, using all available seismic data tied to shallow-water wells. It contains up to 10 km of sediment. An early rift sequence is overlain by a large Late Cretaceous delta, which culminates with the mid-Campanian Rakopi Formation coal measures. This sequence marks the break-up unconformity following the start of Tasman Sea spreading. A passive margin succession follows as the New Zealand mini-continent gradually subsided, with sediments becoming gradually finer grained until carbonates dominate during the Oligocene. Initiation of the present plate boundary around the start of the Miocene, 25 million years ago, caused uplift and renewed clastic deposition in the form of spectacular channel and turbidite complexes. The present reconnaissance seismic grid indicates at least six subtle structures that are each large enough to contain a billion barrels of oil or several trillion cubic feet of gas, suggesting that the first drilling targets may be Late ...