Repsol SA and its partners are claiming the largest natural gas discovery in Indonesia in 18 years and among the 10 largest finds worldwide in the past year, a find that could limit the need for imports in the future.

The Spanish-based major, which operates and holds a 45% stake in the Kali Berau Dalam well, or KBD-2X, onshore in the Sakakemang block in South Sumatra, said the discovery may hold 2 Tcf-plus of recoverable reserves.

Partners in the project are Malaysia’s state-owned Petroliam Nasional Berhad, i.e. Petronas (45%), and Japan’s Mitsui Oil Exploration Co. (10%). Exploratory work is to continue in the coming months with an additional planned appraisal well.

Repsol also is cooperating on the exploration activity with Malaysia’s SKK Migas, the Special Taskforce for Upstream Oil and Gas Business Activities, which manages projects to ensure the resources generate maximum benefits and revenue for the state.

Finding a big gas discovery in Indonesia could reduce the need for liquefied natural gas (LNG) exports to the country, where the gas supply is dwindling. State-owned explorer Peratima on Tuesday agreed to support the Anadarko Petroleum Corp.-led Mozambique LNG export project, agreeing to take 1 million metric tons/year for 20 years.

The KBD discovery is only 25 kilometers (15.5 miles) from the Grissik gas plant, which gathers production from the ConocoPhillips-operated Corridor project before it is sent to buyers in Sumatra, West Java and Singapore.

ConocoPhillips and Pertamina will also be interested in KBD results “as they look for resource that could extend the life” of Corridor, which is set to expire in 2023, noted Wood Mackenzie’s research director Andrew Harwood.

Corridor is a key gas supplier to Singapore and West Java, but it is expected to see “declining output from 2024 — a new source of supply would also be positive news for gas buyers in these markets.”

Harwood said the KBD well was re-entered after it encountered control problems in late 2018 after targeting the pre-tertiary fractured basement play. Before drilling began, the prospect was estimated to hold about 1.5 Tcf of gas, or 250 million boe-plus, he said.

“Further appraisal will be required to determine the extent of the discovery and firm up resource estimates, with another well scheduled on the block for later this year. Wood Mackenzie estimates anything larger than 300 Bcf would be considered commercial, given proximity to gas infrastructure.”

SKK Migas recently has increased efforts to encourage exploration because of dwindling output and a lack of investment, he noted.

“The regulator has targeted the discovery of at least one new giant field (500 million boe) by 2023. The Kali Berau Dalam discovery could be the good news Indonesia needs to kick-start its exploration sector. If pre-drill estimates are realized, it would be the largest discovery in Indonesia since ExxonMobil Corp.’s Cepu discovery in 2001.”

Indonesia is the focus of Repsol’s exploration investments in Southeast Asia, where it holds onshore and offshore licenses in Sumatra. Plans are to execute an “intense drilling and seismic acquisition campaign in 2019 and 2020,” executives said.

Repsol’s exploration and production strategy is focused on developing gas assets, which make up three-quarters of its reserves and two-thirds of output.

Repsol noted that it has made more than 50 hydrocarbon discoveries from 2007-2019, with 10 ranked among the largest hydrocarbon finds worldwide. More than half of the discoveries are already in production.