Kapuni

[1][2] During the Lower Cretaceous (~150–100 Ma) Rangitata Orogeny, an accretionary wedge accumulated and was uplifted on the margin of Gondwana in present-day New Zealand.

[5] A broad marine transgression occurred in the Late Oligocene to Early Miocene (~28–20 Ma), and mudstones were deposited on top of the Eocene organic-rich shales and sandstones.

During this time, north-plunging inversion structures, including the Kapuni Anticline, developed along the Manaia Fault and other rift-structures in the Taranaki Basin's Eastern Mobile Belt.

Further west, in the Taranaki Basin's Western Stable Platform, Cretaceous rift-related faults experienced little strain.

[4][6] Cenozoic compression in the Taranaki Basin has generally been attributed to a change in stress regime caused by the development of the Hikurangi Subduction System between the Pacific and Australian Plates off the east coast of New Zealand's North Island.

[7] Late Eocene compressional structures in the Taranaki Basin correspond with a period of elevated uplift rates along the Alpine Fault on New Zealand's South Island that has also been attributed to the nearby subduction zone.

[1] Like its source rocks, Kapuni's reservoir layers are located in the Eocene Mangahewa Formation and were deposited as part of a general transgressive sequence.

Dextral transpression associated with the Hikurangi Subduction System caused fault reactivation and basin inversion during the Eocene and Miocene, resulting in the development of the Kapuni Anticline.

This is a result of fault block rotation that produced necessary extension along the anticline's younger units during fold growth.

[7] New Zealand's first natural gas field, Kapuni was discovered in 1959 by a team consisting of Royal Dutch/Shell, British Petroleum, and Todd Energy.