Tullow Oil has said it expects to deliver strong first half revenue and gross profit, but that it will book a $415 million (€306 million) exploration write-off charge after disappointing drill results in Mauritania, Ethiopia and Norway.

The poor drill results, combined with licence relinquishments, will lead to a net exploration write off of $415 million for the first half of the year, Tullow said. Post-tax, this will amount to $305 million of which $150 million relates directly to 2014 wells.

Providing guidance in advance of its half year results on July 30th, Tullow said it expects revenue of $1.3 billion and gross profit of $650 million.

The oil and gas producer maintained its full-year production guidance of 79,000-85,000 barrels of oil equivalent per day.