Tap Oil Limited provides the following update on the Zola-1 exploration well, offshore Carnarvon Basin, Western Australia.
Location / Proposed
Depth The Zola-1 well is located in permit WA-290-P, immediately south of the giant Gorgon gas field in the Carnarvon Basin, Western Australia. The well is being drilled in 285 metres of water and the primary Mungaroo Formation target will be intersected at approximately 4,300 metres below sea level. Further secondary targets will see the well drilled to a target depth of 5,000 metres.
Progress
During the period from 06:00 hours WST on 29 December 2010 to 06:00 hours WST on 05 January 2011, Zola-1 was at a depth of 3524 metres. The 340mm (133/8”) intermediate casing was successfully pressure tested, prior to evacuating and securing the rig for an approaching cyclone. The cyclone was ultimately downgraded to a tropical depression and the rig has now been re-manned. This morning the operations were continuing focus on making the well ready for drilling out the intermediate casing shoe.
Forward Plan
Drill ahead in 311mm (121/4”) hole to the second intermediate casing point at circa 3,976 metres, where 244mm (9 5/8”) casing will be run and cemented in the hole.
Zola-1 is now expected reach the first target depth in approximately 15 days and reach a final total depth in approximately 25 day, on a trouble free basis. Upon completion of evaluation the well will be plugged and abandoned in the normal course of offshore operations.
Background
The Zola prospect is a very large Triassic tilted fault block on trend with the giant Gorgon gas field. One of the largest undrilled structural features in the Carnarvon Basin, Zola is covered by high quality newly reprocessed 3D seismic data and is considered a moderate risk prospect. Zola is estimated by Tap to contain mean recoverable gas volumes of 1.0 trillion cubic feet with upside potential for 2.0 trillion cubic feet. The well will test the gas potential of several top and intra Mungaroo Formation sands – the primary reservoir at Gorgon. In addition it is possible that some Jurassic reservoirs may be developed flanking the main Triassic structure.
Previous drilling in WA-290-P focused on the shallower Jurassic and Cretaceous interval, resulting in the Antiope gas discovery in 2000 and the minor Lauda oil discovery in 2005.
Located close to existing and developing gas infrastructure, Zola would have multiple potential development options should it be a discovery. Any development at Zola could also encompass the overlying Antiope gas discovery (estimated at ~120 Bcf).
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Source: Tap Oil, January 5, 2010;