BARROW ISLAND OILFIELD, REVISITED

Abstract

Barrow Island is located 55 kilometres off the NW coast of Australia, 1300 kilometres north of Perth. The first well on the island, drilled by West Australian Petroleum Pty Limited (WAPET) in 1964, discovered a small accumulation of oil in Upper Jurassic sandstone. The fourth well was completed as a shallower oil discovery in the Lower Cretaceous Windalia Sandstone. The Windalia Pool was declared commercial in May 1966 and the first shipment of crude was made in April 1967.

Production peaked at 7300 kilolitres (about 45 000 barrels) per day early in the life of the field and has declined to 3500 kilolitres (about 22 000 barrels) per day. Estimated original oil in place in the Windalia Pool is about 120 million kilolitres (about 760 million barrels) and current trends suggest 40 million kilolitres (250 million barrels) will be recovered.

Pricing policies of the Australian Government have encouraged efforts to locate new reserves and extend the limits of known pools. These efforts on Barrow Island have led to the discovery of three new pools and the extension of the main Windalia Pool to the northwest. Two of the new pools are in unusual reservoir systems while the third has a significant stratigraphic component in its entrapment.

To the end of 1983, WAPET had drilled 670 wells on the island. Further drilling is planned to evaluate the currently known pools and to try to locate further accumulations in this oil-rich area.