significant gross hydrocarbons

ARC Energy advises that, since its last update on 26 March 2008, the Dunsborough 2 appraisal
well in WA-286-P, in the offshore Perth Basin, Western Australia, has recovered a second core
to surface. Both 24 metre cores cut during the last three days had 100% recovery and good oil
shows throughout the 48.6 metre total cored interval from 1,515 to 1,563.5 mBRT.
As at 0600 hours on 28 March 2008 (local time), the current operation at Dunsborough 2 was
recovering Core No 3 in an effort to define the oil water contact.
At top reservoir level Dunsborough-2 is 47 metres down structure from Dunsborough 1, which is
1.6 kilometres to the north and from which light (39 degree API) oil was recovered. The top of
the cored interval in Dunsborough 2 is two metres below the top of the reservoir which was
encountered 25 metres high to prognosis.
Dunsborough 2 is scheduled to reach the proposed Total Depth of approximately 1,680 mBRT
during the next several days.
Subject to completing the coring programme, drilling to Total Depth and running a full suite of
logs, including wireline sampling, this latest well appears to point to a potentially significant
gross hydrocarbon column both at the Dunsborough-2 well and for the field as a whole.
Participating Interests in the WA-286-P Joint Venture are:
Roc Oil (WA) Pty Limited (Operator)........................................ 37.5%
ARC Energy (Offshore PB) Limited...................................... 30.0%
AWE Oil (Western Australia) Pty Ltd........................................ 27.5%
CIECO Energy Australia Pty Ltd................................................ 5.0%