Norton Rose Fulbright is advising Thailand’s PTT Exploration and Production Pcl. and Jakarta-based PT Pertamina on their proposed $1.3 billion acquisition of Indonesian offshore oil and gas assets held by Hess Corp.

PTTEP and PT Pertamina, both state-owned companies, are planning to purchase from Hess a 75 percent stake in the Pangkah oil field in the East Java Sea and a 23 percent share of the Natuna Sea A offshore gas field near the border between Indonesia and Malaysia. Both companies, in separate statements, said the acquisitions are in line with strategic plans to add oil and gas assets to their respective portfolios.

The Natuna Sea purchase is expected to close by the end of December, with the Pangkah transaction following in the first quarter of next year.

Singapore partner Ashley Wright is acting for Norton Rose Fulbright, with help from its Indonesian associate firm Susandarini and Partners.

Freshfields Bruckhaus Deringer Singapore partner Gavin MacLaren is representing New York-based Hess on the deal.