Drilling Update: Exploration

Roc Oil Company Limited 12 June 2007 12 June 2007 ROC OIL COMPANY LIMITED ('ROC') STOCK EXCHANGE RELEASE Drilling Activity Update: Exploration Drilling KEY POINT • Discovery offshore Western Australia and exploration drilling underway onshore Angola. 1. Dunsborough-1, Offshore Perth Basin: ROC: 37.5% & Operator Roc Oil (WA) Pty Limited, a wholly owned subsidiary of ROC, advises that the Dunsborough-1 exploration well, WA-286-P, in the offshore Perth Basin, has been classified as a new field oil and gas discovery. Since ROC's last Stock Exchange Report on 1 June 2007, Dunsborough-1 has been drilled to a Total Depth of 1,755 metres Below Rotary Table and a comprehensive wireline electrical logging and fluid pressure and sampling programme has been completed. Preliminary interpretation suggests that the well has intersected a minimum 25 metre gross hydrocarbon column of which approximately 18 metres is net pay. The accumulation appears to have a small ( < 13 metres) gross gas column above an oil column containing light oil (approximately 40o API) in sands of poor to moderate reservoir quality. Pressure data indicate that the total gross hydrocarbon column associated with the Dunsborough structure may be up to 70 metres. Tentative volumetric estimates by ROC suggest that the structure could contain between 20 and 40 million barrels of oil in-place. As of 0600 hours on 12 June 2007, Australian Western Standard Time ('AWST'), the current operation at Dunsborough-1 was preparing to plug and abandon the well in accordance with the pre-drill schedule. Dunsborough-1, located approximately 25 km south of Geraldton, Western Australia and about 50 km northwest of the Cliff Head Oil Field, is the third and final well in an offshore Perth Basin drilling programme which was initiated in early April, 2007 by the WA-286-P and WA-325-P joint ventures, both of which are operated by ROC. The programme's first well was the Frankland-1 gas discovery in WA-286-P, about 25 km southeast of Dunsborough-1, the programme's second well was the Perserverance-1 gas discovery in WA-325-P, approximately 50 km to the northwest of Dunsborough. Commenting on the three well programme ROC's Chief Executive Officer, John Doran stated that: 'It is always nice to drill three offshore exploration wells and make three discoveries, particularly when that extends the known oil and gas fields some 200 kilometres along regional strike to the northwest of the Cliff Head Oil Field. However, at the end of the day we're not looking to play with exploration success statistics but rather to clock up commercial success - and it will take some time to establish whether or not we have done that. Of the three discoveries, Frankland and Dunsborough look as if they have the best chance of being developed, while Perserverance will probably need a lot of good things to happen around it if is going to make the grade. Whatever the details, it would seem that an exploration programme that was regarded by ROC as the last throw of the dice in the northern offshore Perth Basin, has certainly provided enough success to cause us to move the discoveries on to the appraisal stage and continue to explore around and on trend from them.' Participating Interests in WA-286-P are: Roc Oil (WA) Pty Ltd (Operator)....................................37.5% AWE Oil (Western Australia) Pty Ltd................................27.5% Wandoo Petroleum Pty Ltd (Mitsui & Co Group of Companies)*.........24.0% ARC (Offshore PB) Limited...........................................6.0% CIECO Exploration and Production (Australia) Pty Ltd................5.0% * Subject to a purchase agreement with ARC Energy 2. Massamabala-1, Onshore Angola: ROC 60% & Operator Roc Oil (Cabinda) Company, a wholly owned subsidiary of ROC, advises that, as of 1600 hours on 9 June 2007 (local time), the ROC-owned 'Explorer' rig commenced drilling the Massambala-1 exploration well in the Cabinda South Block, onshore Angola. As at 0600 hours on 11 June 2007 (local time) the current operation was waiting on cement prior to drilling ahead. Massambala-1, a directionally drilled well located on the coastal plain south of Cabinda City, is the first of a minimum five well exploration drilling programme to be operated by ROC onshore Angola during 2007. It is currently anticipated that Massambala-1 will reach a Total Depth of 2,185 metres by early August. ROC will issue Stock Exchange releases documenting the progress and results of its drilling operations in Angola as material information becomes available although this will not necessarily be on a weekly basis. This reporting rationale reflects the fact that oil and/or gas shows are not uncommon in the region and therefore reporting hydrocarbon shows in isolation, as and when they are encountered, regardless of magnitude and prior to receiving additional back-up log data, may not be material. Participating Interests in the Cabinda South Block are: ROC Group Companies (Operator)............60% Force Petroleum Limited...................20% Sonangol P&P S.A..........................20% Commenting on the commencement of drilling onshore Angola, ROC's Chief Executive Officer, Dr John Doran, stated that: 'The commencement of the first well in 35 years onshore Cabinda might be regarded as a significant event, but ROC's focus is not on any sense of occasion, as much as the operational end of our business, including the continuing interaction with the local communities, who have been very supportive of our efforts to date. If these aspects of ROC's work in Cabinda continue to flourish then, from here on in, the rocks should be able to speak for themselves. While nobody can be sure as to what the drill bit will find it certainly looks as if the next many months will be quite an interesting period for the Company and its shareholders.' Damian Fisher General Manager External Affairs & Investor Relations For further information please contact: Dr John Doran on Tel: +61-2-8356-2000 Fax: +61-2-9380-2635 Email: jdoran@rocoil.com.au Or visit ROC's website: www.rocoil.com.au Dr Kevin Hird General Manager - Business Development Tel: +44 20 7495 5707/+61 2 8356 2000 Mob: +44 775136 7149/+61 417 261 727 Email: khird@rocoil.com.au Nick Lambert Bell Pottinger Corporate & Financial Tel: +44 (0)207 861 3232 This information is provided by RNS The company news service from the London Stock Exchange
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