MEXICO CITY, July 16 (Reuters) - Mexican conglomerate Grupo Carso, controlled by billionaire Carlos Slim and his family, said on Thursday it had agreed to buy TotalEnergies' TTEF.PA 30% stake in Block 30, an offshore oil and gas project in Mexico.

After the deal closes, Harbour Energy HBR.L will remain the operator with 70%, while Grupo Carso, through a subsidiary, will hold the remaining 30%, according to a company filing.

Block 30 sits in shallow waters off Mexico's coast and produces a light crude oil. Originally, the block was awarded in April 2018 under a 25-year production-sharing contract through an international public tender.