The Sydney-based company said Basker-4, which has now reached a total depth of 3480m, also confirmed that the top of the structure was about 10m higher than expected and extended west of the initial Basker-1 discovery well.

After casing the well and installing completion equipment, the Ocean Patriot semi-submersible drilling rig will return to Basker-2 to recover pressure gauges and repair a leaking mandrel.

The rig will then move to Basker-3 and Basker-5 to install completion equipment and perforate the wells, in line with the planned development strategy.

Meanwhile, Anzon said the two vessels, Crystal Ocean and the Basker Spirit, will leave the production site and sail to Singapore in the next few days to undergo facility upgrades and inspections ready for connecting to the newly laid pipelines, umbilicals and manifold.

In addition, the company said the total project cost remains on budget at $A304 million, while the full field development starting in the second half of this year is forecast to produce an average rate 25,000 barrels of oil per day.

Last week, Anzon announced that the six-month Basker extended production test (EPT) was successfully concluded as planned, after producing 870,000 bbl of oil.

“The EPT proved to be very successful, not only in the volume of oil produced but in understanding field performance characteristics,” executive director Andrew Young said in a report to the ASX this morning.

“The information gained has had a direct and beneficial impact on completion plans for the other wells, design and operation of long-term production facilities and the potential for additional development drilling and reserves.

“In doing so the EPT has been a most successful risk management tool.”

Anzon and Beach Petroleum are 50:50 joint venture partners in the project.