Rockpool Acqui Regulatory News (ROC)

23 Feb 2005 07:02

Roc Oil Company Limited23 February 2005 23 February 2005 ROC OIL COMPANY LIMITED ("ROC") STOCK EXCHANGE RELEASE DRILLING ACTIVITY UPDATE KEY POINT • Cliff Head-5 ("CH-5"), an appraisal well in the Cliff Head Oil Field, offshore Western Australia, has encountered the top of the anticipated reservoir substantially low to prognosis. Roc Oil (WA) Pty Ltd, as Operator of the WA-286-P Joint Venture (the "JointVenture"), advises that the CH-5 appraisal well has encountered the top of theanticipated reservoir approximately 50 metres low to prognosis just above thefield wide oil-water contact and as of 0600 hours on Wednesday 23 February(Australian Western Standard Time) was drilling ahead at 1,492 metres tobasement. CH-5 is a vertical "pathfinder" well located about 1 km southeast of the CH-1discovery well (Attachment 1*). The pre-drill plan for CH-5 was that it beplugged and abandoned because its primary purpose was to determine the natureand extent of the reservoir in the East Ridge portion of the Cliff Headstructure so as to better define the location of a horizontal development well. It is currently not understood whether CH-5 has come in low to prognosis due toadverse seismic velocity variations which would have an adverse impact on fieldreserves, or due to drilling inadvertently on the wrong side of a nearby fault,which would probably have a less severe impact on field reserves. The Joint Venture is actively reviewing the data obtained to date and willintegrate that information with the results of the logging programme over thenext 48 hours. At the moment, it is too early to comment definitively as towhether or not CH-5 was optimally located in relation to a nearby fault. If thefull data set indicates that the CH-5 location was less than structurallyoptimal, the Joint Venture may consider sidetracking the well. Regardless of the outcome of CH-5, upon completion of well operations the rigwill move to drill the CH-6 development well location in the main horst part ofthe Cliff Head structure. Commenting on preliminary results from CH-5, Dr John Doran, ROC's ChiefExecutive Officer, stated that: "With the results we have seen so far from CH-5 it is pretty clear why wedescribed the well as a 'pathfinder'. If we have ended up on the 'wrong side' ofthe fault, then the situation may possibly be rectified by a sidetrack to theeast. If, however, we are on the 'right' side of the fault, the fact that thetop reservoir has been encountered substantially lower than prognosed means thatwe need to greatly improve our understanding of the East Ridge portion of theCliff Head structure and this will impact on the details and timing of the FinalInvestment Decision for the development of the field." The WA-286-P Joint Venture comprises: Equity Roc Oil (WA) Pty Ltd (Operator).....................37.5% AWE Oil (Western Australia) Pty Ltd ................27.5% Wandoo Petroleum Pty Ltd ...........................24.0% Voyager (PB) Limited ................................6.0% CIECO Exploration and Production (Australia) Pty Ltd .................................5.0% *For Attachment 1 see copy of this release on ROC's website(http://www.rocoil.com.au/Pages/ASX_Releases/2005_Releases/February-2005.html) Bruce Clement For further information please contact:Chief Operating Officer 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 (0)207 586 7935 Fax: +44 (0)207 722 3919 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