Roc told the market this morning that the Premium Murmanskaya jack-up rig started drilling a well designed to test the Wei 6-12 West Prospect, a stratigraphic-structural feature about 2.5km northwest of the Wei 6-12S-1 oil discovery made by the JV in 2006.

Spudded in 30m of water, the Wei 6-12W-1 well is expected to reach a total depth of 2425 metres later this month.

Following this well, the JV – which also involves Horizon Oil, First Australian Resources and Petsec Energy – will drill a well to test the Wei 6-12 East prospect, a structural-stratigraphic feature 1.7km east of the oil discovery.

Roc managing director John Doran said because these first two wells were testing targets that were primarily stratigraphic, not structural, there would be a “commensurate increase in exploration risk and potential commercial reward.”

“The proximity of the first two wells in the program to the two oil accumulations already discovered by the joint venture means that another discovery – or two – would be a healthy addition to the reserve base already established in this part of the block,” he said.

“However, the commercial potential of the existing discoveries is not dependent upon the outcome of the 2008 drilling program.”

The third well in the program will be Wei 12-2-2, designed to appraise a structure in the southern part of the block that tested oil in 1993.

Roc flagged a possible fourth well in the form of a sidetrack/step-out, depending on whether one of the first three wells made a discovery requiring immediate appraisal.

The company said the drilling program was about two weeks behind schedule due to rig equipment malfunctions, which have since been fixed.

As a result, the drilling program is due to be completed by the end of the first quarter of this year.

Interests in Block 22/12 are Roc, as operator with 40%, Horizon with 30%, Petsec with 25% and FAR with 5%.