FURTHER tests by Edinburgh oil and gas group Bowleven have raised expectations of the hydrocarbon potential of its Isongo Marine field off Cameroon.

Shares in the Edinburgh group, which holds significant equity interests in onshore and offshore acreage in Cameroon and Kenya, soared 11% after the latest assessment.

The company said the results represent a material volume addition and confirm the IM-5 well offers "more than sufficient gas volumes" to meet the requirements of a $1 billion fertiliser plant that the government in Cameroon is looking to build.

A memorandum of understanding has already been signed between Bowleven subsidiary Euroil, German firm Ferrostaal and the government to supply gas to the proposed facility.

Bowleven said the result marked an upgrade in the region of "1000% on where they thought the volumetrics would be". The company may comment on the well when it announces its interim results for the six months ended December 31, 2012 on March 20.

The IM-5 well is part of the 9000-square mile (2300 sq km) Etinde permit.

Bowleven chief executive Kevin Hart said: "We are very pleased with the results of the IM-5 well to date, which have significantly exceeded our pre-drill expectations."

Shares in Bowleven closed up 8.75p at 88.5p.