Drilling Update: Perth Basin

Roc Oil Company Limited
29 May 2007



28 May 2007

                         ROC OIL COMPANY LIMITED ('ROC')
                             STOCK EXCHANGE RELEASE

     DRILLING ACTIVITY UPDATE: OFFSHORE PERTH BASIN EXPLORATION DRILLING -
                                 PERSEVERANCE-1

Roc Oil (WA) Pty Limited advises that, as of 0600 hrs Australian Western
Standard Time on 28 May 2007, an extensive wireline evaluation programme had
been completed at the Perseverance-1 exploration well and the well has been
plugged and abandoned as a gas discovery.

Preliminary interpretation of drilling, wireline and pressure data indicates
that the well intersected gas saturated sand over a gross interval of 31 metres
within which there are 28 metres of net gas reservoir. The gas accumulation is
at the top of the objective Permian section, interpreted as being equivalent to
the Dongara Sandstone and possibly the upper Irwin River Coal Measures.
Reservoir quality appears to be poor to moderate.

The Perseverance discovery is located in WA-325-P in the offshore Perth Basin,
approximately 33 km west of Geraldton. The structure has a maximum vertical
relief of approximately 80 metres and is apparently gas-filled. Initial
calculations for the accumulation suggest in-place gas in the range of 20 - 50
BCF.

The forward programme for the Premium 'Wilcraft' rig is to start drilling the
final well in the three well programme, Dunsborough-1 in WA-286-P, approximately
50 km southeast of Perseverance-1 and 25 km northwest of Frankland-1, later this
week.

Participating Interests in WA-325-P are:

Roc Oil (WA) Pty Ltd (Operator)......................................37.5%
Apache Northwest Pty Limited.........................................37.5%
ARC (Offshore PB) Limited............................................20.0%
Wandoo Petroleum Pty Ltd. (Mitsui & Co Group of Companies)............5.0%*
* Subject to a purchase agreement with ARC Energy


Damian Fisher
General Manager
External Affairs & Investor Relations

                                         For further information please contact:
                                                                Dr John Doran on
                                                            Tel: [phone]
                                                            Fax: [phone]
                                                     Email: [e-mail]
                                       Or visit ROC's website: www.rocoil.com.au

                                                                   Dr Kevin Hird
                                          General Manager - Business Development
                                           Tel: [phone]
                                            Mob: [phone]
                                                     Email:  [e-mail]
                                                                                
                                                                    Nick Lambert
                                            Bell Pottinger Corporate & Financial
                                                       Tel:  [phone]
                                                                                


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