It was confirmed on Apr. 20 that the large fixed maritime structure China installed without authorization in the Provisional Measures Zone (PMZ) of the Yellow Sea originated as an oil drilling rig decommissioned after service in the Middle East. China is believed to have purchased the retired rig, expanded and modified it, and placed it in the PMZ under the guise of a “fish farm support facility.” Experts say the installation amounts to a “mini artificial island,” built under the pretense of supporting fisheries in a zone where non-fishing activities—including the construction of facilities and resource extraction—are strictly prohibited. They warned the structure could affect the undefined maritime boundary between South Korea and China.
Satellite imagery analyzed by The Chosunilbo and obtained from U.S. satellite firm SkyFi shows the platform spans approximately 100 meters in width and 80 meters in length. It features an “H”-marked helipad and three steel bridges. About 3 kilometers to the southeast lies another Chinese facility—the octagonal Shenlan-2 platform, which Beijing designated as a new-model fish farm when it was deployed in May 2024.
A ship registry search revealed the structure was originally built in France in 1982 and operated as an oil drilling rig in the Middle East and other regions before its decommissioning in 2016. A similar incident occurred in 2014 when China deployed an oil rig in Vietnam’s exclusive economic zone (EEZ), asserting unilateral control over nearby waters and prompting a confrontation with Vietnam. Analysts suggest China may now be employing a similar strategy in the Yellow Sea—using oil rigs and artificial islands to expand its maritime influence, as it previously did in the South China Sea.
Analysis of satellite photos from the past three years indicates that Shenlan-1 and Shenlan-2—described by China as advanced fish farms—are semi-submersible. They are visible while afloat but disappear from satellite view when submerged, with indications that they may be capable of relocating underwater. In contrast, the fixed platform—converted from the decommissioned oil rig—has remained anchored since its installation near 35 degrees north latitude and 122 degrees east longitude in October 2022.
Recent satellite images taken on Apr. 2 reconfirmed the platform’s presence and showed what appeared to be Chinese vessels leaving wake trails nearby. China has maintained that the structure functions as a “management support facility” for its Shenlan fish farms.
A close-up satellite image shows what appears to be an antenna tower at the center of the platform and two vessels docked along its sides. The structure, which measures 100 meters in length, 80 meters in width, and rises 50 meters high, is said to be capable of housing up to 100 personnel.
“The fixed platform was previously used as an oil drilling rig before being acquired and modified by China,” a South Korean Ministry of Oceans and Fisheries official said on Apr. 20. “Though it’s an older model, its technical specifications indicate it can accommodate around 100 people.” The official added, “At roughly the size of a soccer field, it essentially functions as a small artificial island.”
Analysts warn that the immovable platform may be part of China’s effort to assert de facto control over the area. Alongside Shenlan-1 and Shenlan-2, the structure could be used to hinder South Korean maritime navigation and strengthen China’s territorial presence in the region.
Since Chinese President Xi Jinping declared in 2013 his vision of building China into a “maritime power,” Beijing has steadily expanded its naval footprint in the South and Yellow Seas, deploying numerous small-scale maritime structures equipped with surveillance systems. In 2021, China enacted the Coast Guard Law, granting its coast guard the authority to use force against foreign vessels that infringe on China’s claimed maritime zones.
In February, when South Korea’s Onnuri attempted to approach the Chinese platform for inspection, China dispatched a rubber boat carrying personnel armed with blades to intercept the vessel. The confrontation escalated into a two-hour standoff between South Korean and Chinese coast guard ships.
