Angolan state oil company Sociedade Nacional de Combustíveis de Angola – Empresa Pública (Sonangol) has signed an agreement with Cobalt to acquire the latter’s 40% stake in Blocks 21/09 and 20/11 offshore Angola for $1.75bn.

Sonangol CEO and chairman Francisco Lemos José Maria said: "Over the past seven years, Cobalt International Energy has had outstanding exploration success in Angola’s pre-salt, which will accrue considerable prosperity to the Angolan people over coming generations."

The firms are planning to make final investment decision for the Cameia development in Block 21/09 by the year end with plans to begin oil production in 2018.

The transaction is expected to receive customary approvals from Angolan Government by the end of the year.

Cobalt chairman and CEO Joseph Bryant said: "We are proud of the tremendous success that our partnership with Sonangol has achieved in opening the pre-salt play in the Kwanza Basin with five significant discoveries and a deep portfolio of exploration prospects.

"We remain committed to continuing our joint efforts with Sonangol to move the Cameia development project to sanction by year end."

Independent exploration and production company, Cobalt is has operations in the deepwater US Gulf of Mexico and offshore Angola and Gabon.