In a statement yesterday, Roc accused Pioneer Natural Resources of breaching its farm-in obligations in Blocks H15 and H16 - collectively known as Block H – in the deepwater Rio Muni Basin.

Until the matter is resolved, Roc said it was unlikely the Aleta-H-2 exploration well, which has already been delayed for nearly two years, would be drilled.

Roc managing director John Doran said the JV’s other partners in the project were also seeking arbitration against the Dallas-based company.

"Although matters that go to arbitration are often perceived to be of an extremely complex nature, the reality of the Block H arbitration situation is really quite simple," he said.

"Pioneer wants to cut and run from its farm-in commitment and Roc doesn't believe that it is entitled to do that. Nothing more. Nothing less. That simple."

Under the 2004 farm-in agreement, Pioneer agreed to free-carry Roc through the drilling of two wells – one in each of the permits - in exchange for a 20% interest.

This arrangement left Roc with a 15% stake in the blocks.

Pioneer struck similar arrangements with the other two Block H partners, Atlas Petroleum and Osborne Resources.

The first of the two farm-in wells, Bravo-H-1, was drilled in June 2004, after which the JV agreed to drill a second well, Aleta-H-2, as soon as it received government approval and secured a suitable rig.

But Roc said earlier this year Pioneer decided to pull out of the arrangement, citing higher drilling costs and the enactment of new hydrocarbon legislation in the country.

To ascertain its rights, Pioneer has sought arbitration against Roc and its partners.

As a result, Roc lodged a counter-claim for damages resulting from the contract breach.