The agreement offers PetroChina an exclusive period to agree to invest in about 20% of Block LB-09 in Liberia.

The deal also gives PetroChina a right to invest up to 20% in one or more exploration Blocks in Cote d’Ivoire, The Gambia, Liberia, Senegal and Sierra Leone.

The period will expire by the end of August 2012.

African Petroleum said the investment made by PetroChina is yet to be agreed and remains subject to governmental, regulatory and other third party approvals.