China’s ‘Dream’ Drills Deep-Sea Basalt in South China Sea
China’s indigenously designed ocean drilling vessel “Mengxiang” (Dream) has completed a 30-day trial drilling mission in the South China Sea, successfully coring basalt from the deep-sea basin floor and elevating the country’s deep-sea drilling capability to the 5,000-meter class. According to Xinhua, the mission makes China the third country — after the United States and Japan — to retrieve hard rock samples from a deep oceanic basin using a drilling vessel.
The voyage, organized by the China Geological Survey under the Ministry of Natural Resources and carried out by the Guangzhou Marine Geological Survey, drilled and cored two wells at a water depth of 4,100 meters. The vessel set a national record with a maximum completion depth of 4,929.17 meters and maximum footage of 864.77 meters, ECNS reported.
A Decade in the Making
China launched project demonstration for the “Dream” in 2015, charting an independent research and development path. Before the vessel existed, Chinese scientists had to rent foreign drilling ships. Chief designer Zhang Haibin described the experience in stark terms.
“Back then, we paid huge fees, but the number of Chinese scientists allowed aboard was strictly limited, and the drilled cores could not be brought back to our own country — we had to race against time to conduct scientific experiments on board,” Zhang said. “This passive, restricted experience made us determined to build our own ocean drilling vessel.”
The vessel was officially commissioned in Guangzhou in November 2024. At 179.8 meters long and 32.8 meters wide, the “Dream” can survive a Category 16 super typhoon and is currently the world’s only ocean drilling vessel capable of reaching a drilling depth of up to 11,000 meters. It carries nine onboard laboratories — the largest and most complete set of its kind, including microbiology and natural gas hydrate facilities — and more than 20,000 monitoring points for real-time situational awareness.
Engineering Feats and Scientific Firsts
A key design challenge was navigability: the vessel had to pass under the Shenzhen-Zhongshan Bridge, capping its hull-above-water height at 76.5 meters despite a derrick over 50 meters tall. Zhang’s team adopted a sunken moonpool design — a world first — and, after hundreds of simulations with Shanghai Jiao Tong University and the China Classification Society, achieved operating efficiency 40% higher than comparable international drilling vessels.
The scientific returns were equally significant. Preliminary research confirmed that multiple phases of large-scale volcanic eruptions occurred after the South China Sea spreading ridge migrated, offering key evidence for core questions about the basin’s expansion. As Banyuetan detailed, researchers also discovered a combination of oceanic red beds interbedded with green and dark-green sediments, and at 813 to 864 meters below the seafloor encountered a tens-of-meters-thick sand-mud interbedded structure with clear bioturbation and rich organic matter — the first such discovery in the South China Sea in a deep formation more than 4,000 meters deep and far from land.
Using an independently developed rotary coring tool, the team recovered a 4.27-meter basalt core, with the longest single coring run reaching 8.54 meters. Multiple coring runs exceeded a 100% core recovery rate.
New Frontiers in Deep-Sea Operations
The mission also marked the first time China conducted long-duration, high-intensity continuous coordinated operations with shipborne deep-sea remotely operated vehicles. Two ROVs accumulated over 358 hours of operations at 4,000 meters underwater, with a single continuous operation lasting up to 103 hours.
According to Sun Zhen, a researcher at the Guangzhou Marine Geological Survey and chief scientist of the voyage, the team completed, for the first time in accordance with international ocean drilling standards, the full on-site workflow of core collection, organization, cataloging, cutting, scanning, sampling, testing, and storage.
“The 11,000-meter drill depth is a grand dream of the entire scientific community, requiring us to keep exploring and working hard, step by step to realize it,” said Xu Zhenqiang, director of the Guangzhou Marine Geological Survey, in remarks carried by CNR. “I hope that through the ‘Dream,’ we can advance global understanding of the ocean and the Earth, and work together to build a community with a shared future for mankind.”
What’s Next
The “Dream” will now carry out scheduled science and technology research voyages to advance the development and application of key deep-sea equipment. Under plans announced at its 2024 commissioning, the vessel is expected to complete its first formal ocean drilling voyage within two years. Officials frame the achievement as central to building China into a maritime and sci-tech power.
Open questions remain, including the precise coordinates and scientific targets of the two wells drilled, when the first non-trial voyage will take place, and how the findings on South China Sea spreading-ridge migration will be peer-reviewed. Reaching the ultimate 11,000-meter “drill through the crust” objective will require further technological steps — steps that Chinese scientists no longer need to take aboard someone else’s ship.