A newly submitted report estimates that an additional 5.17 billion barrels of oil and gas reserves may be buried in the Ulleung Basin in the East Sea, according to officials on Feb. 2. The Korea National Oil Corporation (KNOC) has commissioned experts to verify the findings, with the review expected to conclude as early as March. If confirmed, the estimated total oil and gas reserves in the East Sea could rise from the previously announced 14 billion barrels to as much as 19.1 billion barrels.

The drillship West Capella is conducting drilling operations to collect samples of oil and gas, estimated at around 14 billion barrels, from the deep sea off the coast of Pohang, Gyeongbuk, as of December 2024. /Newsis
The drillship West Capella is conducting drilling operations to collect samples of oil and gas, estimated at around 14 billion barrels, from the deep sea off the coast of Pohang, Gyeongbuk, as of December 2024. /Newsis

A KNOC official said a commissioned study submitted in December assessed that “at least 680 million barrels, and up to 5.17 billion barrels, of oil and gas may be present in the Ulleung Basin.” The report is currently undergoing verification.

The assessment was conducted by ACT-GEO, a U.S.-based deepwater technology evaluation firm that previously analyzed the physical survey of the East Sea deep-sea gas field development project known as the “Blue Whale” prospect. The South Korean government announced in June 2024 that the Blue Whale structure could contain up to 14 billion barrels of oil and gas.

The latest findings identify 14 additional prospective sites, with an estimated exploration success rate of around 20%, similar to that of the Blue Whale structure. The reserves are projected to contain between 70 million and 470 million metric tons of natural gas and between 140 million and 1.33 billion barrels of crude oil. The largest identified prospect, named “Goblin Shark,” is estimated to hold up to 1.29 billion barrels of oil and gas.

KNOC stressed that the study results require further verification by experts to refine the reserve estimates and assess their feasibility. The ongoing review is primarily being conducted by domestic experts, including academic researchers. The final figures could change depending on the verification outcome.

For the Blue Whale prospect, the government spent nearly six months conducting expert evaluations and consultations before making its June 2024 announcement. The drillship West Capella has been drilling at the Blue Whale site since December last year. An initial analysis from the drilling is expected to be released between May and June of this year.