LUANDA (Reuters) -Chevron has signed a preliminary agreement with Angola's national oil and gas concessionaire ANPG to explore for oil in the country's offshore block 33/24, the U.S. oil major said on Wednesday.

The risk services contract with Angola's National Oil, Gas and Biofuels Agency was signed on the first day of an energy conference in the country.

"The execution of the RSC remains subject to regulatory approvals," Chevron said in a statement.

The deep-water block is found in the Lower Congo Basin, and is adjacent to the prolific Block 17 and Block 32.