Earlier this week, joint venture partner Cooper Energy announced that heavy rainfall in this area of the Cooper Basin had delayed the start of drilling. The well was originally due to be spudded last Friday.

Cooper yesterday told the Australian Stock Exchange that the well was currently being drilled in a 12¼-inch hole to a depth of 700m, at which point Beach would set a 9 5/8-inch surface casing.

It added that the well was expected to take five days to reach the Namur Formation target, eight days to reach the Hutton Formation and 12 days to reach a total depth of 1931m.

Covering five square kilometres, the Callawonga prospect has 23m of structural relief and contains estimated P50 recoverable reserves of 1 million barrels of oil in the Namur Sandstone and 700,000bbl of oil in the Hutton Sandstone.

Cooper said the prospect has a low risk (32% probability of success), with hydrocarbon charge being the key risk element. Each of the other risk elements (trap effectiveness, reservoir presence and seal) is considered low risk, the company said.

Beach holds a 75% stake in the PEL 92 joint venture, while Cooper Energy owns the remaining interest.