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29 March 2013 @ 09:00 am
Usgs assessment: Taranaki Basin Assessment Unit, New Zealand, 2013  
Assessment of Undiscovered Oil and Gas Resources of the Cretaceous-Tertiary Composite Total Petroleum System, Taranaki Basin Assessment Unit, New Zealand

USGS recently completed an assessment of the conventional undiscovered resources of the Cretaceous-Tertiary Composite Total Petroleum System (TPS), Taranaki Basin Assessment Unit (AU), onshore and offshore New Zealand (fig. 1).




The Cretaceous-Tertiary Composite TPS and Taranaki Basin AU include an area of approximately 153,000 square kilometers (km2). The TPS and AU boundaries are coincident and will be referred to as the AU. The offshore portion of the AU makes up approximately 80 percent of the total area. Water depths range from 0 to 1,500 meters. The AU includes Cretaceous and Tertiary rocks in all or part of the Taranaki, Wanganui, and Deep-Water Taranaki Basins (fig. 1).

Situated on the Australian tectonic plate, the AU consists of an onshore and offshore eastern graben complex and an offshore western stable platform. The graben complex and stable platform developed during Jurassic and Late Cretaceous–Paleogene rifting events between Australia and New Zealand that created a rift sag basin and the Tasman Sea. The Late Cretaceous–Paleogene rifting was followed, from 35 to 24 million years ago (Ma), by a relatively continuous period of regional compression and initiation of subduction of the Pacific plate. Collision of the Australian and Pacific plates resulted in the Australian plate overriding the Pacific plate on North Island and the Pacific plate overriding the Australian plate on South Island creating a plate inversion zone between the North and South Islands. The southernmost portion of the AU, between the North and South Islands, is part of the plate inversion zone. Back-arc extension related to subduction started approximately 4 Ma and continues today.

The source rocks include Cretaceous and Paleogene marine and lacustrine shales and mudstones and Cretaceous and possibly Jurassic coals. Oil and gas generation occurred as early as Late Cretaceous in the deep-water part of the AU (Deep-Water Taranaki Basin) (Uruski and Warburton, 2010). Due to a varied
burial history, generation has continued intermittently in different parts of the AU throughout the Cenozoic and is ongoing today in parts of the AU. The Taranaki Basin is filled with as much as 9 km of sediments. Maximum burial depth occurred during late Miocene in much of the basin. Migration is primarily along fault zones and into adjacent reservoirs.

Cretaceous and Tertiary reservoir rocks and potential reservoir rocks include turbidites, carbonates, alluvial sandstones, and volcaniclastics. Traps are primarily structural. Collisionrelated late Tertiary tectonics created three primary structural trap types—faulted anticlines, overthrusts, and tilted fault blocks (Crown Minerals, 2011). Seals are primarily shales and mudstones. Production is mainly from sandstones of the Eocene Kapuni Group and Oligocene Otaraoa Formation. There are eight discovered oil accumulations and twelve gas accumulations with a grown size (maximum expected volume of production) greater than the 5 million barrels of oil equivalent minimum assessed size (IHS Energy, 2010). Two fields, Kapuni and Maui, presently account for over 80 percent of New Zealand’s gas production and condensate (Crown Minerals, 2011). The Kapuni and Maui fields formed in faulted anticline traps.



USGS estimated mean volumes of 487 million barrels of oil, 9.8 trillion cubic feet of gas, and 408 million barrels of natural gas liquids.
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487 million barrels of oil = 66.4 млн т. нефти
9.8 trillion cubic feet of gas = 274.4 млрд. м3

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BP Statistical Review of World Energy June 2012

Нет своей добычи нефти и газа

2011
Oil: Consumption = 6.9 млн.т
Natural Gas: Consumption = 3.9 млрд. м3

Максимум
Oil: Consumption (2007-2008)= 7.2 млн.т
Natural Gas: Consumption (2001) = 5.9 млрд. м3