Austral Pacific Plans to Flow Cardiff Gas Zones Independently
The Cardiff-2A gas well, in the deep PEP 38738 in central onshore Taranaki, is to be worked over to allow different gas zones to flow independently, operator Austral Pacific Energy says.
In a news release, Austral Pacific says the work-over will pull the 4.5 inch tubing and replace it with 2 7/8 inch production tubing and a packer assembly, to isolate each of the three Kapuni gas zones tested. This will be conducted when rig and equipment are available. Until then, the well is suspended.
Austral Pacific, which holds a 36.5% interest in the deep permit, says initial testing operations have now been completed at Cardiff-2A with three zones jointly tested.
The shallowest zone (McKee sands) has consistently flowed gas at rates of 1-1.5 million cubic feet per day, with an average 27% CO2 content and 30-35 barrels per million cubic feet of condensate.
The flow rates were inhibited by substantial water production, with some gas, from the underlying zone, the K1A. The water from this zone loaded down the well stream by being flowed to the surface through the 4.5 inch tubing used for the fraccing operation. This is not an optimal gas lift configuration, and the water inhibited the flow potential of all zones, Austral Pacific says.
The deepest K3E sands have not flowed to the potential indicated by electric logs and by their early performance immediately after being perforated and hydraulically fracced. The reasons for this are not obvious at present, the company says.
Austral Pacific's CEO, Dave Bennett says, "We have a genuine discovery in the McKee sands, which have good reserve potential across the whole structure. We are confident that a re-completion of the well will result in commercial flow rates from the McKee, substantially better than those we have achieved to date.
"With respect to the deeper zones, the K1A is unlikely to be pursued further in this well, and will be isolated so that it does not impede the other zones," he says.
The K3E remained an open possibility, and may yet flow at good rates, according to Dr. Bennett.
In early 2006, Austral Pacific plans to acquire a 3D seismic survey over the whole structure, which will enable them to identify production 'sweet spots' in the McKee sands, and to optimally place further production wells. The 3D survey will also assist in mapping of the Cheal oil field in the shallow portion of the same permit.