Operator Roc Oil said the three day test was constrained by surface facilities and yielded 33.1 degree API oil with a gas oil ratio of 100 cubic feet per barrel.

"The flow rate is very encouraging, particularly in view of the fact that, prior to the test, CH-3-chl appeared to have the poorest quality reservoir of the four wells which have penetrated the Cliff Head Oil Field during the last 13 months.

"The result is also significant for at least two other technical reasons; if the field is developed, it will be via horizontal wells which are expected to be substantially more productive and it has convincingly demonstrated the benefits which can be gained by applying ESP technology to fields like Cliff Head."

The Ensco 53 drilling rig was preparing to relocate to the nearby Twin Lions prospect, which has an estimated size of 350 million barrels of oil.