Discovery gives hope to other Atlantic explorers

Rockhopper is one of four junior exploration companies looking for oil in the seas around the Falklands.

As well as the Sea Lion prospect, the company has a 7.5 per cent interest in the Liz prospect, a site 50km to the east of where it is now drilling. Desire Petroleum has a majority interest in Liz and was the first company to use the Ocean Guardian, the rig that was towed thousands of miles from Aberdeen to be used by several companies for test drilling.

Last month, Desire said it had found only traces of hydrocarbons when drilling at a depth of 2,550m (8,360ft). "Oil may be present in thin intervals but reservoir quality is poor," it added.

Once Rockhopper has completed its testing in about two weeks, the rig will be moved to the east of the islands, to a project known as Toroa, where Falkland Oil and Gas will begin its exploration programme.

The area around Toroa has never been explored before, but Falkland Oil and Gas points to seismic data suggesting there are up to 1.7bn barrels at the well. The company says it will take between 30 and 35 days before the results are known. The rig will then return to Rockhopper and Desire for further exploration.

A fourth explorer, Borders & Southern Petroleum, has assets to the south of the Falklands in seas too deep for the Ocean Guardian. It is still trying to secure the use of a rig.