Tullow Oil has reported a 48 per cent increase in pre-tax profit to $829 million for the first six months of 2012.

The London-based Irish exploation group said first-half net income rose 63 per cent to $567 million as revenue reached $1.2 billion.

The company said its TEN fields off Ghana hold mostly oil and it plans to start the project development by the end of the year.

The Tweneboa, Enyenra and Ntomme fields hold most likely 360 million barrels of oil equivalent, of which 70 per cent is crude rather than natural gas, it said. The figures are lower than Tullow had originally estimated.

"Initially we thought that area might be quite gassy, but actually the appraisal program has shown it to be predominantly oil," Tullow chief operating officer Paul McDade said.

"We are targeting sanction of the project towards the year end," he said.

Tullow last year estimated the TEN fields would require at least $4 billion in investment to produce as much as 125,000 barrels of oil a day.

Bloomberg