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Panoramic view of the Donghae gas field operated by Korea National Oil Corporation. / Korea National Oil Corporation

Most of the core facilities at the Donghae gas field—spared from immediate decommissioning under a plan by the South Korean government and Korea National Oil Corporation (KNOC) to repurpose them for carbon capture and storage (CCS) and offshore wind projects—have now been slated for dismantling. KNOC plans to dismantle production wells, subsea infrastructure, and offshore platform jackets by 2030. Following the end of gas production in late 2021, these facilities were left in the East Sea with the intent to reuse parts of the site for CCS and offshore wind power, but the initiatives have stalled for years without tangible progress.

According to KNOC's "Restoration Plan Pursuant to the Donghae Gas Field Restoration Order" obtained by Asia Today on the 16th, the dismantling of the Donghae gas field will begin in earnest in October 2029 and wrap up by 2030. Most assets—spanning a 61-kilometer subsea pipeline, topside and subsea installations, production wells, and exploration wells—have been included on the demolition list. Decommissioning the offshore platform jackets is known to require heavy-lift vessels (HLVs), dive support vessels (DSVs), and two barges. Given that this marks South Korea's first large-scale decommissioning of offshore oil and gas production infrastructure, international contractors may take part in the upcoming bidding process.

KNOC maintains that decommissioning cost estimates cannot be disclosed to avoid compromising the fairness of the competitive bidding process. An official from KNOC stated, "We will proceed with decommissioning work after establishing a plan that factors in safety and cost efficiency, preparing the bid, and conducting the bidding procedures to ensure full safety."

The government sought a preliminary feasibility study in August last year for a CCS project utilizing the Donghae gas field, but withdrew the proposal citing weak economic feasibility, and has yet to announce follow-up measures. No plans to reapply for the study have been established so far this year. An official from the Ministry of Climate, Energy and Environment offered only a boilerplate response, noting, "The situation requires careful consideration, and the matter remains under review."

KNOC maintains that the current restoration plan does not signal an outright abandonment of repurposing the facilities for CCS and offshore wind power. A KNOC official explained, "We are reviewing CCS and offshore wind projects in accordance with relevant laws, government policies, and permitting procedures," adding, "Specific project plans, including whether to reuse existing infrastructure, remain under comprehensive review taking overall conditions into account."

The Donghae gas field is South Korea's first commercial gas development, linked via the Donghae-1 and Donghae-2 production facilities, which elevated the country to the ranks of the world's 95th oil-producing nation. Commercial operations began in July 2004 and concluded in December 2021, with the site operating unmanned since January 2023. The offshore platform is a massive structure installed in waters 152 meters deep, standing 200 meters tall and weighing roughly 14,000 tons. At the time of construction, it was engineered to withstand earthquakes measuring 5.5 to 6.5 in magnitude. KNOC previously dismantled the onshore production facilities in 2023 while leaving the offshore platform and subsea assets intact to explore their reuse for CCS and offshore wind power.

                                                                                                          Bae Seok-won