Amity Oil sets test at Whicher Range tight gas field in Western Australia

Amity Oil NL, Perth, will return to Whicher Range gas field in the onshore Perth basin early next year with an exploration program designed to unlock reserves in the tight reservoir. The Whicher Range 5 will use state-of-the-art technology that has been successful in similar US fields.


By an OGJ Online Correspondent

MELBOURNE, July 24 -- Amity Oil NL, Perth, will return to Whicher Range gas field in the onshore Perth basin early next year with an exploration program designed to unlock reserves in the tight reservoir.

The Whicher Range 5, a well designed by tight reservoir specialist Stim-Lab Inc., will use state-of-the-art technology that has been successful in similar US fields.

Amity said the hole would be drilled conventionally to the top of the target Sue group and then with air drilling through a 650 m gas sands section to minimize fluid contact that could damage the reservoir. Fracture treatments would use a mixture of carbon dioxide and oil.

Heritage Group Ltd., Perth, has farmed into the project, taking a 31.5% interest through a subsidiary.

Whicher Range is the largest known but undeveloped onshore gas field in Australia. About 215 km south of Perth in Western Australia, it has closure of 150 sq km and estimated resources of 3.7 tcf. Flow rates have been measured at up to 1.9 MMcfd for short periods from individual sands with cumulative rates up to 5 MMcfd over multiple zones.

Union Oil Development Corp. opened the field in 1969. Several companies have been unable to sustain commercial flows. For instance, Pennzoil Co. operated a program in 1997-98 that used a mix of water, potassium chloride, and a polymer gel for fracturing. But the condensate formed an emulsion with the water to clog fractures and swelling authigenic clays in the reservoirs added to the problem.

Gas production could be sold to the mineral sands industry at Bunbury on the coast and gas-fired electricity generation. A line to Bunbury would allow a link to the Dampier-Bunbury pipeline and access to Perth markets.

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