The Woollybutt-4 well has now been logged to its total depth with sidewall cores and pressure data acquired in the Upper Barrow sandstones. The well has now been suspended to allow future re-entry and the rig demobilized.
The secondary target in Woollybutt-4, some 40 meters beneath the upper zone where a 6 meter gross oil column was intersected in the nearby Woollybutt-3 drilled in 1999 may also have a small oil column, however attempts to collect a sample were unsuccessful and hence this remains undetermined. The pressure information infers the presence of lateral seals which if present would auger well for potential future production from this zone if oil is found to be present. Analysis of the 18 meter cored section through this zone will be required before any further comment can be made on the possible commerciality of this zone.
Woollybutt Field Production Impacts
The field is presently producing around 22,500 bopd from the existing wells, Woollybutt-1H and 2H.
The Scallybutt-1H well located in the northern lobe is scheduled for completion as a third horizontal production well in February this year. Scalybutt-1H is interpreted by Tap to have the potential to access additional volumes of oil from the northern lobe of around 2-10 million barrels depending on the reservoir quality horizontally away from the initial vertical well. Scalybutt-1H oil is expected to be on line by around mid 2005, and will be the third producing well in the northern lobe (Woollybutt-1HST and 2HST and Scalybut-1H).
Tap's preliminary estimate of potential additional recoverable volumes of oil remains at around 10 million barrels in the upper reservoir. No volumes have been attributed to the lower zone in the Upper Barrow at this stage as this will require a detailed evaluation of all available data including laboratory examination of the cored section.
The Woollybutt-4 well is being suspended to allow for re-entry and completion as a potential future horizontal production well in the interpreted crest of the southern lobe of the Woollybutt structures.
Realization of Tap's pre-drill estimate of the upside case of around 15 mmbls for the southern lobe, will require an additional appraisal well to be drilled further south for Woollybutt-4.
The Joint Venture will now assess the development options for the southern lobe. At this early stage, Tap expects the preferred plan to be a tie-in to the existing FPSO facility located on the northern lobe some 6 kilometers to the north by around Q1 & 2 of 2006.
Whilst at this early stage it is not possible to provide detailed guidance on future overall field production rates, inclusive of the contributions from Scalybutt-1H and the southern lobe, the results of Woollybutt-4 and the upcoming tie-in of Scalybutt-1H will clearly extend the life of the Woollybutt field considerably.
Further, it is likely that the nearby Woollybutt Southeast prospect will also be considered for drilling in the very near future given the success of Woollybutt-4.
WA-234-P Joint Venture participants are Eni Australia as operator with 65%; Mobil Australia Resources with 20% and Tap Oil with 15%.
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