Harbour Energy has agreed to divest its operated interests in the Natuna Sea Block A field and the Tuna development project in Indonesia to Prime Group for a total of $215m (£161.27m) in cash. 

The deal includes Harbour’s 28.67% operated interest in Natuna Sea Block A, which includes the Anoa, Bison, Gajah Baru, Gajah Puteri, Iguana, Naga and Pelikan fields. 

It also includes the UK-based oil and gas company’s 50% operated interest in the Tuna development project, which contains the Kuda Laut and Singa Laut discoveries. 

Natuna Sea Block A produced around 4,000 barrels of oil equivalent per day (boepd) during the nine months ended 30 September 2025. 

Harbour had booked proved plus probable reserves of 7.4 million barrels of oil equivalent (mboe) for Natuna Sea Block A, and proved and probable contingent resources of 54mboe related to Tuna, as of year-end 2024. 

The transaction is expected to be completed in the second quarter of 2026, contingent on regulatory approvals and customary closing adjustments. 

Upon closing, Harbour will continue its operations in Indonesia through its Andaman Sea interests. 

The effective date for the Natuna Sea Block A sale is 1 January 2025, while the Tuna project transfer will be effective upon completion of the transaction. 

Houlihan Lokey served as the sole financial advisor to Harbour on this transaction. 

Harbour Indonesia business unit managing director Steve Cox said: “This transaction marks a key milestone for Harbour in Indonesia and supports our strategy to focus capital and resources on our most competitive and material opportunities. 

“It is also a significant moment for our colleagues in the country, whose hard work and commitment have built Natuna Block A and Tuna into high-quality assets over many years. I wish them well as they enter a new chapter under the experienced ownership of Prime Group.” 

Prime Group, which operates both upstream and downstream oil and gas businesses in Indonesia, currently holds a 25% interest in the producing Natuna Sea Block B field. 

Last year, Harbour Energy completed a multi-well campaign across the Andaman Sea acreage, which led to gas discoveries at Layaran and Tangkulo at Andaman South. 

Harbour also secured a 60% operated interest in the Central Andaman licence, which includes an extension of the Layaran discovery. 

In May this year, Harbour Energy announced plans to cut its UK workforce by a quarter, equating to around 250 jobs, citing government policies. 

The decision, affecting the Aberdeen unit, is driven by reduced investment due to the UK Government’s stance on the North Sea fossil fuel industry.