Photo:CNOOC

A trial program focused on domestically made equipment for natural gas hydrate (NGH) exploration has been completed in the South China Sea, China National Offshore Oil Corp (CNOOC) told the Global Times on Monday. 

The trial broke two records in China's NGH exploration - maximum drilling depth and maximum operating water depth - which proved the reliability and duration of domestically made drilling equipment and provided valuable operation experience for subsequent formal explorations.

The trial started in June at a predetermined depth of 1,758 meters in the South China Sea and was completed within two weeks. It helped the research team from CNOOC get first-hand data including land formations, temperatures and size of the drilling well, relying on domestically built exploratory vessels, deep-water drilling systems and measuring equipment. 

Zhou Shouwei, an academician of the Chinese Academy of Engineering, noted that the success of the trial means China has fully localized NGH drilling equipment with the capabilities of ships, drilling equipment, logging, coring, online analysis and testing in the field of deep-water and ultra-deep-water NGH drilling and sampling.

CNOOC started related equipment research and development in 1995 and gradually built a drilling system based on 708 deep-water investigation vessels. 

The system helped CNOOC sample the core of NGH rock in the sea area southeast of South China's Hainan Province in 2019. 

"The successes of the trial helped China become the third country that possesses domestic drilling and sampling techniques of NGH in deep water," said Zhou, adding that China had entered a new era of deep-sea NGH exploration.

NGH, also known as flammable ice, is one of the most promising strategic resources for commercial development. It is mainly found on the bed of the South China Sea at a depth of 800 meters. 

China previously hired overseas professional operators and equipment to complete sampling of NGH due to the complex nature of the work, such as the risk of landslides during drilling, and lack of drilling equipment.