WEST PERTH, Western Australia - Drilling has begun on the Woollybutt-4H development well, kicking off the Woollybutt South development.
The Woollybutt-4H development well, in the Barrow sub-basin in permit WA-25-L, is a sidetrack being drilled from the existing Woollybutt-4 well. TheSonga Venus semisubmersible drilling rig re-entered the previously drilled Woollybutt-4 well and drilled out the cement plugs before drilling the Woollybutt-4H sidetrack, which will be completed as a horizontal well in the Top Barrow sandstones.
The Woollybutt South lobe was discovered by the Woollybutt-3A well in 1999 and subsequently appraised by the Woollybutt-4 and Woollybutt-5A wells. Planned wells include a Woollybutt-6 appraisal well.
The Woollybutt-4 and Woollybutt-6 wells are expected to add 10 MMbbl in reserves from the greater Woollybutt development.
According to the WA-25-L partners, preparations are on schedule for an early 2008 tie-in of the two wells by subsea flowlines to theWoollybutt Four Vanguard FPSO. The tie-ins are expected to increase production to approximately 14,000 b/d of oil.
When the Woollybutt-4 re-entry is completed, theSonga Venus semisubmersible will move on to drill Woollybutt-6.
Eni Australia Ltd. operates the WA-25- L permit with 65% interest. Partners include Tap West Pty. Ltd. with 15% interest and Mobil Australia Resource Co. Pty. Ltd. with 20% interest.