"Mengxiang" Successfully Completes Trial Drilling in the South China Sea, Retrieving Basalt Samples from the Deep Ocean Basin

en.Wedoany.com Reported - Recently, the "Mengxiang" ocean drilling vessel returned to Guangzhou after completing its trial ocean drilling mission in the South China Sea. The voyage lasted 30 days, during which two wells were drilled and cored in the South China Sea at a water depth of 4,100 meters. Basalt samples from the South China Sea basin were successfully retrieved, making China the third country in the world to successfully retrieve hard rock samples from a deep ocean basin using a drilling vessel.

According to reports, the "Mengxiang" achieved a maximum completion depth of 4,929.17 meters and a maximum footage of 864.77 meters on this voyage, setting a new record for the maximum water depth drilling operation independently carried out by China, marking that China's deep-sea drilling high-efficiency coring capability has entered the international advanced ranks. The team used independently developed rotary coring tools to successfully retrieve a 4.27-meter basalt core sample, making China the third country in the world, after the United States and Japan, to retrieve hard rock samples from a deep ocean basin using a drilling vessel. At the same time, this voyage, for the first time in accordance with International Ocean Discovery Program (IODP) standards, completed the entire process of on-site core sample collection, organization, cataloging, sectioning, scanning, sampling, testing, and archiving with multi-parameter processing and analysis. Multiple drilling runs achieved core recovery rates exceeding 100%, forming a full-process operational capability for ultra-deepwater ocean scientific drilling.

Maximum completion depth 4,929.17 meters

The team also innovatively established a risk prevention and emergency response system for ultra-deepwater high-difficulty well drilling, and for the first time conducted long-duration, high-intensity continuous collaborative operations with shipborne deep-sea remotely operated vehicles (ROVs). Two ROVs accumulated over 358 hours of operations at a water depth of 4,000 meters, with the longest single continuous operation lasting 103 hours, successfully completing tasks such as wellhead environment assessment, depth warning, and drilling monitoring.

Based on a large number of valuable core samples and data obtained during this voyage, preliminary research has confirmed that multiple phases of large-scale volcanic eruptions occurred after the jump of the South China Sea spreading ridge, providing key empirical evidence for solving core scientific questions such as the expansion of the South China Sea, and is expected to revolutionize scientific understanding of the formation and evolution of the South China Sea. At the same time, the team discovered an interbedded combination of oceanic red beds and green-dark green sediments during drilling, and encountered a tens-of-meters-thick sand-mud interbedded sedimentary structure at 813–864 meters below the seafloor, with strata accompanied by obvious bioturbation and rich in organic matter. This is China's first discovery of such characteristics in deep strata at a water depth exceeding 4,000 meters in the South China Sea and far from land, which is of great significance for studying the paleoenvironmental evolution of the South China Sea.

Drilling site

Coring operation

Sample processing

This voyage was organized by the China Geological Survey of the Ministry of Natural Resources and implemented by the Guangzhou Marine Geological Survey. A total of 170 scientific expedition members from 9 institutions, including the China Geological Survey, China Oilfield Services Limited, Peking University, China State Shipbuilding Corporation Limited, China University of Geosciences (Wuhan), Hainan University, and Hainan Tropical Ocean University, participated.