PetroChina signed an agreement with Qatar Petroleum, representing the government of the State of Qatar, who authorized PetroChina Investment to acquire from GDF SUEZ Exploration Qatar B.V. 40 percent of the exploration and production rights under its Qatar's Block 4 Exploration and Production Sharing Agreement, said the company on its website July 25.

GDF SUEZ, with 60 percent stake, will remain as the operator of the block.

Block 4 is an offshore block located in the northern sector of Qatar, close to the North Field. It extends for over 2,500 square kilometers in area at water depths up to 75 meters, the website said.

With the formal signing of the agreement, the two partners - GDF SUEZ and PetroChina - will begin drilling in Block 4 by the next few months.