Western Southland Basins

Basin Summary

Complex Tertiary tectonics superimposed on earlier rifting has created a large number of potential traps. The presence of thick successions, thick coals, oil shales, seeps and a show in Parara-1 together suggest good potential for exploration.

• Western Southland Basins Fact File [696 kB PDF]
• Western Southland Basins Map [521 kB JPEG]
   

Key facts

Location A region of about 40,000 sq km on and offshore the far south of the South Island. Geology Basin-fill of up to 9,000 m of Early Cretaceous to Recent sedimentary rocks, deposited in fluvial to deep marine settings. Wells Four modern wells drilled to >600 m (two offshore). Many shallow holes drilled for oil, gas and coal seam gas.

Hydrocarbons

No discoveries. Gas seeps, oil shales, degraded oil in outcrop, and a show in the 1975-1976 offshore well Parara-1 indicate an effective petroleum system. Coal seam gas in Cretaceous and Eocene coal measures in the Waiau Basin.

Prospects

Plays include anticlines, stratigraphic pinch-outs, and drapes over pre-existing basement relief. Coal seam gas at Ohai may be commercial.

Source rocks

Cretaceous syn-rift sediments, especially the Ohai Group, with some potential in Eocene lacustrine mudstones.

Reservoir rocks

Late Cretaceous and Eocene fluvial sandstones; Oligocene turbidites; Miocene turbidite sandstones in the offshore.

Port facilities

South Port
www.southport.co.nz

• New Zealand Infrastructure and Port Facilities [1.25 MB PDF]

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