Spudded last Wednesday, Manta-2 had on Sunday drilled to a depth of 971 metres and set the 13 3/8-inch intermediate casing.

But after pressure testing the well, Anzon discovered the casing string had mechanically parted at the crossover from the 13 3/8 to 20 inch casing at a depth of about 163 metres.

Consequently, the well was plugged and a new well path will start today, Anzon said. This means the Manta-2 well plan will be extended by about five days.

Anzon said all other Manta-2 operations had gone according to plan, with no adverse safety incidents.

With a planned total depth of 3102 metres, Manta-2 is expected to be completed by mid February, after which the Ocean Patriot will move to Basker to drill three additional wells as part of the full field development (FFD) plan.

Once completed, the FFD would be capable of producing up to 35,000 barrels of oil per day from all wells completed in the two fields, according to Anzon.

Meanwhile, the Crystal Ocean FPSO restarted production to the shuttle tanker, Basker Spirit, on the weekend, after successfully selling the first oil cargo from the Basker Manta development.

Anzon CEO Steven Koroknay told EnergyReview.net the joint venture expected to make deliveries every five to six weeks during extended production testing of 10,000 barrels per day.

"In the third quarter following full field development, we're looking at producing an average 25,000 barrels per day, with deliveries occurring every two to three weeks," Koroknay said.

"This will be without the Basker Spirit, which is leaving the site."

Production at the Basker-2 well was reduced to about 8000 bpd from the upper interval, down from 10,000 barrels, to prepare for opening the lower interval later this week, Anzon said.

Operator Anzon Australia and Beach Petroleum are 50/50 partners in the Baska-Manta joint venture.