AWE also believes it can extract an additional million of barrels of crude from the field for the June 2008 year.

This is the second reserves upgrade for the Tui, Amokura and Pateke oil pools in less than a year.

AWE this morning said the new 2P figure compared with estimated reserves of 27.9MMbbl, on which the project was first sanctioned, and an interim re-estimate of 32MMbbl following completion of the development drilling campaign during mid-2007.

The increase in reserves followed a re-assessment of the field based on interpretation of reprocessed 3D seismic, a more detailed assessment of the producing Eocene-aged Kapuni reservoir, and the integration of production data from the wells since production began in late July.

AWE said Tui had produced about 4.4MMbbl, achieving recent production rates of up to 50,000bbl per day, the processing limit of the floating production storage and offloading vessel Umuroa.

Production water being produced from the field was at substantially lower rates than expected, the company added.

It further said that based on current reservoir and facility performance, together with the reserves upgrade, it had revised gross production for the year to June 2008 from 10MMbbl to about 11MMbbl.

Meanwhile, preliminary planning for a fourth production well, Tui-4H, has begun, with drilling targeted for 2009.

The Tui partners are operator AWE (42.5%), Mitsui E&P NZ (35%), New Zealand Oil & Gas (12.5%) and Pan Pacific Petroleum (10%).